Evocalcet with vitamin D receptor activator treatment for secondary hyperparathyroidism.

This ad hoc analysis of a previously conducted phase 3 head-to-head comparison study of evocalcet and cinacalcet in secondary hyperparathyroidism patients undergoing maintenance hemodialysis evaluated the efficacy and safety of combined once-daily oral evocalcet and intravenous vitamin D receptor activator treatment stratified by weekly vitamin D receptor activator dose (117, 45, and 91 patients in no, low [< 1.5 μg], and high [≥ 1.5 μg] dose groups, respectively). Effects of vitamin D receptor activator were assessed on the basis of intact parathyroid hormone, corrected calcium, phosphorus, and fibroblast growth factor-23 levels; percent changes from baseline; proportions of patients who achieved target intact parathyroid hormone, corrected calcium, and phosphorus at Weeks 28-30; and adverse drug reactions. Intact parathyroid hormone, corrected calcium, phosphorus, and fibroblast growth factor-23 levels decreased in all groups; phosphorus and fibroblast growth factor-23 levels remained high in the high dose group. In the low and high dose groups, greater proportions of patients achieved the corrected calcium target compared with the no dose group (p = 0.043). Ratios of intact-to-C-terminal fibroblast growth factor-23 decreased in all groups. In low and high dose groups, hypocalcemia was less common than in the no dose group (p = 0.014). Evocalcet with concomitant vitamin D receptor activator demonstrated benefits such that more patients achieved the corrected calcium target and exhibited decreased fibroblast growth factor-23 synthesis; the incidence of hypocalcemia also decreased. Clinical trial registration: ClinicalTrials.gov (NCT02549391) and JAPIC (JapicCTI-153013).

Introduction

Patients with severe chronic kidney disease requiring dialysis exhibit a decline in renal function that controls calcium and phosphate metabolism. This impairment subsequently causes various mineral and bone disorders, such as secondary hyperparathyroidism (SHPT) [1-3]. Patients with SHPT have elevated circulating parathyroid hormone (PTH), calcium and phosphorus levels, and increased levels of bone turnover markers and fibroblast growth factor-23 (FGF23), leading to an increased risk of cardiovascular morbidity and mortality [4].

FGF23, first reported in 2000, is synthesized in osteocytes and involved in the regulation of phosphorus reabsorption and 1,25(OH)2 vitamin D production [5, 6]. Recent studies revealed a significant association between elevated serum FGF23 levels and poor prognosis, cardiovascular events, and increased all-cause mortality in hemodialysis patients [7-12]. FGF23 is also associated with left ventricular hypertrophy in chronic kidney disease patients and, therefore, it is critical to control circulating FGF23, PTH, and mineral levels [13-15].

A vitamin D receptor activator (VDRA) preparation administered intravenously (IV) is the standard therapy for patients with SHPT in Japan, but recently, calcium-sensing receptor agonists, termed calcimimetics, have been developed and demonstrated a significant improvement in the balance between serum calcium, PTH, phosphorus, and FGF23 levels [16-25]. Evocalcet, the latest calcimimetic drug approved in Japan, causes nausea and vomiting less frequently than another calcimimetic drug, cinacalcet [26, 27], which suggests that it might better achieve target PTH and calcium levels in patients with SHPT who are on maintenance hemodialysis.

Because of the recent development of calcimimetics, patients with SHPT are often treated with combination therapy consisting of VDRA and a calcimimetic drug. Indeed, approximately 50% of patients who participated in a previously conducted phase 3 randomized study to compare the efficacy and safety of evocalcet with cinacalcet (phase 3 head-to-head comparison study) were treated with concomitant IV VDRAs [26]. Although VDRAs and calcimimetics may reduce PTH levels to a similar degree, they have different effects on calcium, phosphorus, and FGF23 levels [28-34]. Therefore, it is of clinical interest to investigate how the efficacies of various calcimimetics are affected by concomitant VDRA therapy.

The current study evaluated the efficacy, including that on FGF23, and safety of evocalcet in the presence (low and high VDRA use) or absence of concomitant IV VDRA using a data set obtained from the previous phase 3 head-to-head comparison study in patients with SHPT who were on hemodialysis.

Materials and methods

This study was conducted at 89 study sites in Japan from October 2015 to November 2016. The ethics committees at all sites (S1 Table) approved the study protocol, and the study was conducted in accordance with the principles of the Declaration of Helsinki and in compliance with the Pharmaceuticals, Medical Devices, and Other Therapeutic Products Act, and Good Clinical Practice (Ministry of Health, Labour and Welfare Ordinance No. 28 dated March 27, 1997). The full study procedures were explained, and written informed consent was obtained from all patients prior to participation.

Previous phase 3 head-to-head comparison study

Patients

Patients with SHPT and on maintenance hemodialysis were eligible for participation in the previous phase 3 head-to-head comparison study of evocalcet and cinacalcet [26]. The inclusion criteria were age ≥ 20 years, stable chronic renal failure treated with hemodialysis three times weekly for ≥ 12 weeks, mean intact PTH level > 240 pg/mL during screening at 2 weeks and 1 week before starting treatment, and serum corrected calcium (cCa) level ≥ 9.0 mg/dL during screening.

Study procedure

Detailed study procedures of the phase 3 head-to-head comparison study were described previously [26]. Briefly, the randomized, double-blind, intrapatient dose-adjustment, parallel-group study comprised a 28-week dose adjustment period (Week 0 to 1 day before Week 28) and a 2-week evaluation period (Week 28 to Week 30). During the dose adjustment period, the starting dose of once-daily oral evocalcet was determined based on the serum intact PTH level 1 week prior to treatment initiation: patients with < 500 pg/mL received 1 mg/day and those with ≥ 500 pg/mL received 2 mg/day that was further adjusted at 1 mg increments up to 8 mg on the day of dialysis based on the dose adjustment criteria.

Concomitant medication and therapy, including cinacalcet (from 2 weeks prior to screening to the end of the study), bisphosphonates, denosumab, teriparatide, and parathyroid intervention (from 24 weeks prior to screening to the end of study), and peritoneal dialysis (between Week 12 and Week 30), were prohibited. Changes in prescribed dialysis conditions (dialysate calcium concentration, dialyzer, dialysis time, and number of dialysis sessions per week) were prohibited from 2 weeks prior to screening to the end of the study.

During the period from 2 weeks before screening until the end of the study, initiation of or changes in preparation, dose, and dosing regimen of IV and oral VDRA medications or derivatives (calcitriol, maxacalcitol, falecalcitriol, alfacalcidol, and eldecalcitol) were not permitted. However, dose reduction or discontinuation of VDRA preparations and derivatives were allowed if the serum cCa level was > 11.0 mg/dL after the start of the study treatment. Furthermore, initiation of treatment with VDRA preparations and derivatives or any dose increase was permitted if either of the following conditions were met: corrected serum calcium level decreased below 7.5 mg/dL and remained at ≤ 7.5 mg/dL after the dose increase or initiation of a calcium preparation; or appearance of clinical symptoms potentially attributable to hypocalcemia that did not improve after the initiation or dose increase of a calcium preparation.

The initiation of phosphate binders, calcium preparations, or food with a phosphate binding effect was not allowed for patients who were not already receiving these preparations or food during this period.

Study design and patients

This ad hoc analysis was designed to analyze the efficacy and safety results of the previous phase 3 head-to-head comparison study, stratified by the baseline weekly IV VDRA dose: patients in the evocalcet arm treated with no VDRA as no dose group (NDG); < 1.5 μg/week VDRA as low (L)DG; ≥ 1.5 μg/week VDRA as high (H)DG. The prescribed weekly dose of VDRA derivatives was converted to an equivalent calcitriol dose (e.g. 10 μg of maxacalcitol was equivalent to 1.5 μg of calcitriol). Both male and female patients were included in the present study.

Efficacy and safety endpoints

The efficacy endpoints were 30 weeks of mean serum levels of intact PTH, cCa, phosphorus, and intact and C-terminal FGF23 levels, and their percent changes from baseline, as well as numbers and percentages of patients who achieved the targets of intact PTH (60 to 240 pg/mL), cCa (8.4 to 10.0 mg/dL), and phosphorus (3.5 to 6.0 mg/dL) during the evaluation period [35, 36], stratified by the VDRA dose. Ratios of intact-to-C-terminal FGF23 in all patients by VDRA dose, as well as the mean expression levels of bone turnover markers (bone specific alkaline phosphatase [BAP] and tartrate-resistant acid phosphatase-5b [TRACP-5b]) by VDRA dose were evaluated. The mean daily dose of evocalcet was presented by VDRA dose.

Safety endpoints were incidences of pre-determined hypocalcemia-related (cCa decreased, blood calcium decreased, and hypocalcemia) and upper gastrointestinal tract-related (nausea, vomiting, abdominal discomfort, abdominal distension, and decreased appetite) adverse drug reactions (ADRs) by VDRA dose.

Statistical methods

Efficacy was evaluated in the per protocol set (PPS), which excluded the following patients: those who did not receive treatment with evocalcet, who had no intact PTH measurement after starting the treatment with evocalcet, who did not meet any inclusion criteria or met any of the exclusion criterion, who were prescribed evocalcet for ≥ 28 weeks with an adherence rate of < 70%, who received prohibited concomitant medication or therapy, who did not have two or more intact PTH measurements from three timepoints during the evaluation period (Weeks 28 to 30), or who had a protocol violation that might have affected the efficacy evaluations. Safety was assessed in the safety analysis set, which included all patients except those who did not receive treatment with evocalcet.

For the patient baseline characteristics, categorical data were summarized using frequencies and percentages, and continuous data were summarized using descriptive statistics consisting of the number of patients, mean, and standard deviation by DG. Categorical data were analyzed using the χ2 test, and continuous data were analyzed using the Kruskal–Wallis test or analysis of variance according to the date distribution. For between-group comparisons of the percentages of patients who achieved the targets, crude differences and 95% confidence intervals were calculated, which were adjusted further for age (< 65 and ≥ 65 years), sex, intact PTH level (< 500 pg/mL and ≥ 500 pg/mL) at baseline and previous cinacalcet treatment. The χ2 test was used for statistical analysis. Differences in changes in intact PTH, corrected calcium, and phosphorus from baseline to Week 30 among three DGs were analyzed by a repeated linear mixed model. Pearson’s correlation coefficient and linear mixed-effects modeling were used to assess the relationship between intact and C-terminal FGF23 levels, and the level of correlation was shown as adjusted R-squared. The ratio of intact-to-C-terminal FGF23 at each time point was normalized to the baseline ratio in each DG. For intact FGF23 levels, those ≥ 80,000 pg/mL were excluded from the analyses. Changes in the ratio of intact-to-C-terminal FGF23 between Week 0 and Week 30 were analyzed by a generalized linear mixed model. All pre-determined ADRs were summarized by preferred term according to the Medical Dictionary for Regulatory Activities version 19.0, and between-group differences were analyzed using the χ2 test. Statistical analyses were performed using SAS version 9.4 (SAS Institute, Cary, NC, USA), and two-tailed p-values < 0.05 were considered statistically significant.

Results

Patients

Of 320 patients randomized to receive evocalcet in the previous phase 3 head-to-head comparison study [26], 317 patients were included in the safety analysis set and 253 patients were included in the PPS (117, 45, and 91 were treated with no, low, and high IV VDRA, respectively) in this ad hoc analysis.

Patient baseline characteristics were similar among the three DGs in the PPS, including the proportions of males and females (range: males 65.8% to 76.9% and females 23.1% to 34.2%) (Table 1). However, a significantly higher number of prior cinacalcet users were included in the HDG compared with the other DGs (p < 0.001), and the baseline mean BAP level was lower (p = 0.015) and the C-terminal FGF23 level was higher (p = 0.031) as the concomitant VDRA dose range increased.

Table 1

Baseline characteristics of study patients.

Parameter (unit)		Weekly VDRA dose
		0	< 1.5 μg	≥ 1.5 μg	p-valuea
		N = 117	N = 45	N = 91
Male, n (%)		77 (65.8)	30 (66.7)	70 (76.9)	0.193
Age (years)		62.4 (10.6)	62.0 (11.9)	58.6 (11.8)	0.050
Body mass index (kg/m2)		24.18 (4.23)	25.36 (5.24)	24.70 (4.60)	0.317
Primary disease, n (%)	Diabetic nephropathy	35 (29.9)	11 (24.4)	20 (22.0)	0.464
	Chronic glomerulonephritis	47 (40.2)	15 (33.3)	42 (46.2)
	Nephrosclerosis	14 (12.0)	5 (11.1)	12 (13.2)
	Other	21 (17.9)	14 (31.1)	17 (18.7)
Duration of dialysis (months)		121.2 (86.7)	122.0 (82.6)	135.4 (87.4)	0.468
Dry weight (kg)		60.51 (12.97)	64.02 (15.52)	63.54 (14.10)	0.188
Dialysis efficiency (spKt/V)		1.510 (0.285)	1.473 (0.299)	1.488 (0.285)	0.730
Cinacalcet use before screening, n (%)		61 (52.1)	24 (53.3)	70 (76.9)	< 0.001
VDRA use at Week 0, n (%)		81 (69.2)	45 (100.0)	91 (100.0)	< 0.0001
	IV	0 (0.0)	45 (100.0)	91 (100.0)
	Oral	81 (69.2)	0 (0.0)	0 (0.0)	-
Intact PTH (pg/mL)		438.9 (197.7)	382.2 (125.8)	409.6 (168.0)	0.183
Corrected calcium (mg/dL)		9.5 (0.6)	9.5 (0.5)	9.6 (0.5)	0.374
Phosphorus (mg/dL)		5.6 (1.2)	5.7 (1.4)	5.9 (1.4)	0.383
Calcium corrected-phosphate product (mg2/dL2)		53.35 (11.00)	54.46 (13.48)	56.36 (13.23)	0.217
BAP (μg/L)		18.79 (10.63)	18.42 (10.66)	15.61 (8.18)	0.015
TRACP-5b (mU/dL)		816.00 (387.62)	773.51 (392.01)	745.76 (405.17)	0.184
Total P1NP (μg/L)		452.51 (304.75)	461.33 (297.93)	405.86 (258.40)	0.530
Whole PTH (pg/mL)		203.58 (91.73)	190.63 (79.76)	190.48 (89.93)	0.274
Intact FGF23 (pg/mL)		18,082.25 (19,267.33)	21,363.44 (20,641.90)	25,365.10 (24,136.73)	0.051
C-terminal FGF23 (RU/mL)		14,414.73 (17,677.51)	18,293.33 (23,928.71)	23,488.03 (34,396.35)	0.031
Largest parathyroid gland volume (mm3)		321.97 (566.19)	256.92 (261.39)	364.11 (791.89)	0.846

Unless otherwise specified, data are presented as the mean (standard deviation).

aχ2 test (categorical), Kruskal–Wallis test or analysis of variance (continuous).

Abbreviations: BAP, bone specific alkaline phosphatase; FGF23, fibroblast growth factor-23; IV, intravenous; PTH, parathyroid hormone; P1NP, procollagen type 1 amino-terminal propeptide; TRACP-5b, tartrate-resistant acid phosphatase-5b; VDRA, vitamin D receptor activator.

Intact PTH, cCa, phosphorus, and bone turnover markers

After the initiation of treatment with evocalcet, the mean intact PTH level gradually decreased in all DGs by Week 30 (NDG vs LDG, p > 0.1; NDG vs HDG, p < 0.0001; LDG vs HDG, p = 0.0025). The mean percent reductions in intact PTH from baseline were also increased throughout the 30 weeks of treatment, irrespective of concomitant VDRA dose (Fig 1A, S2 Table). The mean cCa level decreased until Week 4 after treatment initiation and remained at a similar level in all DGs with slightly lower levels in the NDG and LDG compared with the HDG (NDG vs LDG, p > 0.1; NDG vs HDG, p = 0.0019; LDG vs HDG, p > 0.1). A similar tendency was observed for the mean percent changes in cCa levels, irrespective of concomitant VDRA dose (Fig 1B, S2 Table). The mean phosphorus levels and mean changes in the phosphorus levels tended to show moderate reductions over the study period (all between-groups, p < 0.0001) (Fig 1C, S2 Table). However, no significant difference was observed for the intact PTH, cCa, or phosphorus level among the three DGs when the levels were adjusted according to their respective baseline levels (all cases, p > 0.95).

Fig 1

Mean levels (left) and mean percent changes from baseline (right) in (A) intact PTH, (B) corrected calcium, (C) and phosphorus levels stratified by concomitant baseline IV VDRA weekly dose in patients with SHPT treated with evocalcet for 30 weeks. IV, intravenous; PTH, parathyroid hormone; SHPT, secondary hyperparathyroidism; VDRA, vitamin D receptor activator.

The mean BAP level was slightly increased at Week 6 and gradually returned to the baseline level at Week 30 in all DGs (Fig 2A). Mean TRACP-5b levels gradually decreased in all DGs throughout the 30 weeks of the study period (Fig 2B).

Fig 2

Mean levels of serum BAP (A) and TRACP-5b (B), stratified by concomitant baseline IV VDRA. BAP, bone specific alkaline phosphatase; IV, intravenous; SHPT, secondary hyperparathyroidism; TRACP-5b, tartrate-resistant acid phosphatase-5b; VDRA, vitamin D receptor activator.

Intact PTH, cCa, and phosphorus guideline target achievement rates

The proportions of patients who achieved the intact PTH target in the LDG and HDG were slightly higher than that in the NDG, but no significant difference was found among the DGs. The proportion of patients who achieved the cCa target was significantly higher as the VDRA dose increased (p = 0.043). The proportion of patients who achieved the phosphorus target was similar among the DGs. The proportion of patients who achieved intact PTH, cCa and phosphorus targets was similar among the DGs, although it was slightly higher in the HDG compared with the other DGs (Table 2).

Table 2

Numbers, percentages, and between-group differences of patients who achieved the target parameters during Weeks 28 to 30 stratified by concomitant baseline IV VDRA dose.

	Weekly VDRA dose
	0	< 1.5 μg	≥ 1.5 μg	p-valuea
Patients who achieved the guideline target level	N = 117	N = 45	N = 91
Intact PTH, n (%)	80 (68.4)	34 (75.6)	70 (76.9)	0.349
Difference (95% CI)		7.2 (−9.01, 20.72)	8.5 (−3.81, 20.16)
Adjusted difference (95% CI)		4.6 (−11.90, 18.50)	11.5 (−1.83, 23.83)
Corrected calcium, n (%)	70 (59.8)	32 (71.1)	69 (75.8)	0.043
Difference (95% CI)		11.3 (−5.47, 25.66)	16.0 (3.12, 27.84)
Adjusted difference (95% CI)		9.8 (−7.35, 24.91)	16.4 (2.75, 28.86)
Phosphorus, n (%)	86 (73.5)	31 (68.9)	58 (63.7)	0.318
Difference (95% CI)		−4.6 (−20.83, 9.84)	−9.8 (−22.27, 2.81)
Adjusted difference (95% CI)		−4.6 (−21.20, 10.31)	−13.2 (−26.23, 0.17)
The above three parameters, n (%)	45 (38.5)	16 (35.6)	38 (41.8)	0.768
Difference (95% CI)		−2.9 (−18.21, 13.90)	3.3 (−9.89, 16.51)
Adjusted difference (95% CI)		−5.1 (−21.00, 12.19)	4.2 (−9.94, 18.21)

aχ2 test.

Adjusted for baseline age, sex, intact PTH level, and previous cinacalcet treatment.

Abbreviations: CI, confidence interval; IV, intravenous; PTH, parathyroid hormone; VDRA, vitamin D receptor activator.

Daily evocalcet doses

The mean daily evocalcet doses were increased at Week 4, when a dose increase was permitted, and showed a gradual increase until the end of the dose adjustment period in all DGs (mean ± standard deviation at Week 27: 3.32 ± 2.38, 3.91 ± 2.46, and 3.34 ± 2.43 mg/day in the NDG, LDG, and HDG, respectively) with a slightly higher mean dose in the LDG compared with the other DGs.

ADRs

Overall, 18.6% (59/317) of patients experienced pre-determined hypocalcemia-related ADRs, and a significant difference was found among the three DGs with the highest incidence rate in the NDG (p = 0.003). The incidence of hypocalcemia in the NDG was the highest compared with the LDG and HDG (p = 0.014). Also, 12.9% (41/317) of patients experienced pre-determined upper gastrointestinal tract-related ADRs without significant differences in the incidence rates (Table 3).

Table 3

Incidences of ADRs stratified by concomitant baseline IV VDRA dose.

	Weekly VDRA dose			All
	0	< 1.5 μg	≥ 1.5 μg		p-valuea
	N = 152	N = 55	N = 110	N = 317
Hypocalcemia-related ADRs, n (%)	40 (26.3)	5 (9.1)	14 (12.7)	59 (18.6)	0.003
Corrected calcium decreased	23 (15.1)	2 (3.6)	12 (10.9)	37 (11.7)	0.072
Blood calcium decreased	7 (4.6)	3 (5.5)	1 (0.9)	11 (3.5)	0.184
Hypocalcemia	10 (6.6)	0 (0.0)	1 (0.9)	11 (3.5)	0.014
Upper gastrointestinal tract-related ADRs, n (%)	16 (10.5)	10 (18.2)	15 (13.6)	41 (12.9)	0.337
Nausea	10 (6.6)	1 (1.8)	5 (4.5)	16 (5.0)	0.368
Vomiting	6 (3.9)	4 (7.3)	4 (3.6)	14 (4.4)	0.522
Abdominal discomfort	4 (2.6)	1 (1.8)	5 (4.5)	10 (3.2)	0.562
Abdominal distension	0 (0.0)	1 (1.8)	1 (0.9)	2 (0.6)	0.311
Decreased appetite	3 (2.0)	3 (5.5)	2 (1.8)	8 (2.5)	0.312

aχ2 test.

Abbreviation: ADR, adverse drug reaction; IV, intravenous; VDRA, vitamin D receptor activator.

FGF23

The mean intact and C-terminal FGF23 levels in the HDG were higher than those in the NDG and LDG at baseline and throughout the treatment period. After starting treatment with evocalcet, the intact and C-terminal FGF23 levels were decreased in all DGs (Fig 3). The percent reductions from baseline in intact FGF23 and C-terminal FG23 in the LDG were significantly higher than those in the HDG throughout the 30 weeks of treatment (p < 0.005 and p < 0.030, respectively). The ratio of intact-to-C-terminal FGF23 in all DGs was 1.2 from Week 0 to the measurement time point at Week 6, which indicates a higher intact FGF23 level compared with the C-terminal FGF23 level (Fig 4). The ratio in the NDG and LDG decreased to 1.1 at Week 12 and then to 0.9 at Week 30 (vs HDG, p < 0.007); however, the reduction in the HDG was not as marked (1.1 at Week 30).

Fig 3

Mean levels (left) and mean percent changes from baseline (right) in (A) intact FGF23 and (B) C-terminal FGF23 levels stratified by concomitant baseline IV VDRA weekly dose in patients with SHPT treated with evocalcet for 30 weeks. IV, intravenous; SHPT, secondary hyperparathyroidism; VDRA, vitamin D receptor activator. FGF23, fibroblast growth factor-23.

Fig 4

Intact FGF23-to-C-terminal FGF23 mean (standard error) ratios, stratified by concomitant baseline IV VDRA.

FGF23, fibroblast growth factor-23; IV, intravenous; SHPT, secondary hyperparathyroidism; VDRA, vitamin D receptor activator.

The adjusted R-squared was similar among the DGs in Week 0 and did not show a notable change at Week 30 (Fig 5). The slope of the FGF23 intact and C-terminal relationship at Week 0 and Week 30 was 0.6717 (95% CI, 0.6489, 0.6946) and 0.7230 (95% CI, 0.7038, 0.7422) in all patients, 0.6359 (95% CI, 0.5981, 0.6736) and 0.6927 (95% CI, 0.6583, 0.7271) in the NDG, 0.6596 (95% CI, 0.6228, 0.6965) and 0.6950 (95% CI, 0.6436, 0.7464) in the LDG, and 0.6936 (95% CI, 0.6566, 0.7307) and 0.7376 (95% CI, 0.7085, 0.7667) in the HDG, respectively. The slope of the FGF23 intact and C-terminal relationship significantly increased after treatment with evocalcet at Week 30 compared with Week 0 in all patients (0.04874 [standard error 0.01307], p = 0.0002) and patients in the NDG (0.06729 [standard error 0.01917], p = 0.0005).

Fig 5

Correlations between intact FGF23 and C-terminal FGF23 at Week 0 and Week 30.

(A) all patients, (B), patients with no concomitant treatment of IV VDRA, (C) patients with IV VDRA < 1.5 μg/week, and (D) patients with IV VDRA ≥ 1.5 μg/week. Circles with a sold line, Week 0; triangles with a broken line, Week 30. FGF23, fibroblast growth factor-23; IV, intravenous; VDRA, vitamin D receptor activator.

Discussion

The current ad hoc analyses demonstrated that evocalcet was effective at reducing the intact PTH, cCa, phosphorus, TRACP-5b, BAP, and FGF23 levels, irrespective of concomitant IV VDRA. The clinical benefit of evocalcet with IV VDRA was also found for hypocalcemia.

Although the difference was not statistically significant, we found that over the 30 weeks of treatment, intact PTH levels tended to be slightly lower in the LDG and HDG compared with the NDG; indeed, > 7% of patients achieved the target with VDRA compared with those receiving evocalcet alone, which indicates that evocalcet and VDRA might have additive effects. Treatment with evocalcet and VDRA showed similar but significant effects on the cCa levels: > 10% patients achieved the target compared with evocalcet alone. Treatment with evocalcet alone decreased cCa levels below the target range in some patients, which was likely prevented by concomitant VDRA, thereby improving the achievement rate. Indeed, patients treated with concomitant VDRA developed hypocalcemia-related ADRs less frequently than those without VDRA. Therefore, evocalcet and VDRA appear to complement each other in the regulation of calcium levels, leading to further clinical improvements. However, unlike intact PTH and cCa, VDRA had no impact on the proportion of patients who achieved the phosphorus target.

Accumulating evidence suggests that elevated FGF23 levels are associated with increased mortality in patients undergoing hemodialysis [7-10]. Although the mechanism by which elevated circulating FGF23 levels increase mortality is not fully understood, it is accepted that FGF23 levels should be better controlled [15]. As previously reported for cinacalcet [12], our results showed that evocalcet decreased intact and C-terminal FGF23 levels. However, overall serum FGF23 levels tended to be higher as the VDRA dose increased, consistent with previous studies [30-32]. Furthermore, while the percent changes in the HDG stopped decreasing after Week 12, those in the LDG kept decreasing, which suggests that a combination of low range IV VDRA and evocalcet provides better control over FGF23 levels.

A lowered intact-to-C-terminal FGF23 ratio indicates a reduction in FGF23 synthesis; therefore, our results suggest that evocalcet decreased FGF23 levels by suppressing FGF23 synthesis irrespective of concomitant VDRA, although this effect was significantly lower in the HDG compared with the other DGs partly because VDRA stimulates FGF23 synthesis. The suppression of FGF23 synthesis by evocalcet was further supported by our finding that the slope at Week 0 was increased at Week 30 with the highest slope change found in the NDG. In addition to FGF23, favorable effects of the combination therapy were found for levels of the bone turnover markers TRACP-5b and BAP. The timing of the changes in the FGF23 coincided with that of BAP. Because FGF23 is synthesized in osteoblasts and osteocytes [5, 6], it would be of clinical interest to elucidate any interactions among these markers and their clinical implications on the prognosis of SHPT in responding to a combination therapy with calcimimetics and VDRA. Furthermore, because elevated levels of FGF23 and bone turnover markers have been presented as prognostic factors [7, 12, 37, 38], further studies are needed to evaluate the long-term effects of this combination therapy.

We observed the clinical benefit of combination therapy with evocalcet and VDRA for pre-determined hypocalcemia-related ADRs. Although upper gastrointestinal tract-related ADRs were slightly increased by the addition of VDRA, this increase was negligible, and no notable new hypocalcemia- or upper gastrointestinal tract-related safety concerns were observed.

In this study, the daily evocalcet dose in the LDG was slightly higher than that in the other DGs. Because evocalcet and VDRA both reduce serum intact PTH levels, patients receiving the lower VDRA dose range were assumed to be treated with a higher range of evocalcet daily doses to supplement the efficacy of VDRA. The combination of IV VDRA and evocalcet dose ranges applied to patients in the LDG appeared to be more beneficial than in the HDG because LDG patients had equivalent efficacy to the HDG but with potentially better long-term prognosis related to lower phosphorus and FGF23 levels. However, differences among the three DGs obtained in this study, such as an elevated FGF23 level [29-34], and/or differential patient baseline characteristics that included a higher proportion of patients with prior cinacalcet use in the HDG, might have been a consequence of the ongoing VDRA treatment. A post hoc analysis of the previously conducted Evaluation of Cinacalcet Therapy to Lower Cardiovascular Events (EVOLVE) trial, in which the effects of cinacalcet on cardiovascular disease were investigated in severe SHPT patients on maintenance hemodialysis treatment, reported that, in most patients, the doses of cinacalcet, VDRA, and phosphate binders were not adjusted just after or at ≥ 14 days after the onset of hypocalcemia [39], which indicates that further studies are needed to confirm whether a high dose range of VDRA is beneficial for the treatment of SHPT patients with oral calcimimetics. Considering the advantages and disadvantages of the combination therapy, treatment options and doses need to be finely adjusted dependent on individual patient disease state, conditions, and characteristics.

This study had some limitations. First, differences in the 30 weeks of mean changes and percent changes from baseline in the intact and C-terminal FGF23, BAP, and TRACP-5b levels were not statistically tested within and among the three DGs. Therefore, any longitudinal mean changes and between group differences in levels need to be interpreted as tendencies. In addition, all patients were Japanese, the study had a small sample size, and patients were treated with evocalcet only up to 30 weeks. Although evocalcet was developed in Japan and has only recently been approved for the treatment of SHPT in patients on maintenance dialysis, it is expected that long-term studies will be conducted in the near future to determine the efficacy and safety of evocalcet in other global populations with larger sample sizes.

In conclusion, treatment with evocalcet improved the achievement rate of the serum cCa target, decreased FGF23 levels by suppressing FGF23 synthesis, and decreased the incidence of hypocalcemia in the presence of VDRA, demonstrating the additive benefits of the combination therapy in SHPT patients.

List of Institutional Review Boards (IRBs).

(DOCX)

Click here for additional data file.

Standard deviations of the mean levels and mean percent changes from baseline in intact PTH, corrected calcium, and phosphorus levels stratified by concomitant baseline IV VDRA weekly dose in patients with SHPT treated with evocalcet for 30 weeks.

(DOCX)

Click here for additional data file.

13 Apr 2021

PONE-D-21-07286

Evocalcet with vitamin D receptor activator treatment for secondary hyperparathyroidism

PLOS ONE

Dear Dr. SHIGEMATSU

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Taisho Toyama Pharmaceutical, Fuji Pharma, and FUSO, and lecture fees from KKC,

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Additional Editor Comments (if provided):

The reviewers, in particular the reviewers 1 and 2 have made important questions and suggestions regrading approach, lack of some information, methodological e statistical aspect , which have be considered and addressed by the authors. Therefore, a deep revision is still necessary at this moment.

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Reviewers' comments:

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Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

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Reviewer #1: Partly

Reviewer #2: Yes

Reviewer #3: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: No

**********

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Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: Yes

**********

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Reviewer #2: Yes

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Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Major comments

1. If I understand correctly the present analysis has been performed only in the patients of the evocalcet group of the parent head-to-head comparison study. This should be made clear from the outset. In the parent trial 320 patients were randomized to receive evocalcet. In the present ad hoc analysis only 253 patients were included. Why were the remaining 67 patients excluded ?

2. VDRA stands for calcitriol and a group of other active vitamin D compounds. Authors further need to tell from the outset which active vitamin D compounds were administered, and to which extent the administered doses were comparable.

3. Eighty-one patients among the 117 weekly zero VDRA dose patients were on oral VDRA therapy at baseline. Did they continue or was this therapy stopped at trial initiation ?

4. In the Results section authors repeatedly mention « trends » for changes of various biochemistry values but actually fail to provide P values in the Figures or Figure legends. Therefore, I conclude that none of these « trends » corresponded to changes reaching the level of statistical significance. The terms « trend » and « trended » should be deleted and instead any non significant change should be acknowledged as no change. This will require a serrious revision of the interpretation of numerous results.

5. Strictly speaking, hypocalcemia is not an ADR, all the more since the calcimimetic-induced decrease of serum PTH goes along with a decrease in serum calcium, at least in ESKD patients on dialysis therapy. It would be interesting to have information on usual hypocalcemia-associated clinical symptoms and signs.

6. In a related post-hoc analysis of the EVOLVE trial in hemodialysis patients receiving cinacalcet therapy - not quoted by the authors - Floege et al found that in the majority of hypocalcemia episodes changes in calcium administration were the preferred treatment option (DOI: 10.1016/j.kint.2017.12.014). In that trial, adjustments of cinacalcet or vitamin D sterol doses were made only in a minority of hypocalcemia episodes. This observation, together with the observation in the present study that high-dose VDRA treatment was associated with significantly higher serum FGF23 levels than low-dose VDRA treatment, and the notion that higher FGF23 levels are associated with higher mortality risk, would rather plead against systematic VDRA administration in dialysis patients on calcimimetic therapy. The authors may want to make this clear in the Discussion.

Minor remarks

Abstract should tell that evocalcet was administered orally. Moreover, authors need to indicate, both in Abstract and in Methods section, that the head-to-head comparison of the parent trial was between evocalcet and cinacalcet.

Abstract L37. I wonder whether the term « clinical benefits » is appropriate here, at least as far as FGF23 is concerned. As to the lesser incidence of hypocalcemia I would like to know whether concomitant vitamin D receptor activator treatment was more effective in avoiding hypocalcemia-associated symptoms and signs.

Introduction. The statement that IV administration of VDRA « is the

standard therapy for patients with SHPT » is incorrect as such. At least in the Western world VDRA can by given either orally or intravenously for the treatment of SHPT.

Discussion, lines 238-284. The statement is inappropriate that « intact PTH levels were slightly lower in the LDG and HDG compared with the NDG » since the difference was not statistically significant.

Reviewer #2: This study is an ad hoc analysis of a previous phase 3, head-to-head comparison study of hemodialysis patients with hyperparathyroidism, after 30-day treatment with evocalcet. This study was conducted at 89 study sites in Japan (Oct 2015-Nov 2016) and demonstrated a non-inferiority to cinacalcet to suppress iPTH with fewer gastro-intestinal adverse events.

This study has demonstrated that the association of oral evocalcet with vitamin D activator was beneficial, with lower synthesis of FGF-23, lower incidence of hypocalcemia and with more patients achieving the calcium target. This oral formulation of evocalcet, was also associated with a reduction of gastric symptoms when compared with oral cinacalcet.

This study confirms the benefit of the treatment of hyperparathyroidism with an association of a calcimimetic + vitamin D.

The reduction of gastric symptoms verified with evocalcet will contribute for a better adherence of this new oral treatment for hyperparathyroidism.

However, the intravenous administration of etelcalcetide after hemodialysis, assures the patient adherence to this kind of treatment.

Evocalcet will be very useful for the treatment of patients with hyperparathyroidism who develop gastric symptoms associated with cinacalcet and who have no conditions for a three times/week intravenous treatment. This will be the case, for instance, of DP patients.

Reviewer #3: This paper reported an ad-hoc analysis results using patients enrolled in one treatment arm of a completed phase III trial. Patients were categorized into three groups according to average weekly VDRA dose. Many clinical outcomes and adverse drug reactions were compared among these three groups. However, almost all statistical analysis only employed basic statistical tests and multiple testing adjustment was not implemented. In addition, most statements about the dose effect of VDRA were without rigorous statistical evidences presented. A professional statistician is recommended to be involved for rigorous data analysis and drawing conclusions.

Specifically,

1. Figure 1 displayed longitudinal mean measurements for each group of patients. It would be helpful to also include variations in the plots. In addition, linear mixed models are recommended to do a formal comparison among three patients groups and make conclusions rather than just looking at the plots and stating there was a tendency of VDRA dose-dependent trend.

2. Table 1 implies that these three groups of patients were not balanced in all baseline measurements. Therefore, the corresponding result comparisons should consider adjusting for these possible confounding factors.

3. A conclusion from Figure 4 says "The slope of the FGF23 intact and C-terminal relationship increased after treatment with evocalcet at Week 30 compared with Week 0 in all patients, as well as by VDRA DG." First, the estimated slope were not reported. Second, a formal statistical analysis should be implemented here to provide support of such statement.

Minor comments:

1. The title of Table 2 says "Mean numbers and percentages...". However, outcomes in Table 2 are all binary ones. It is confusing why there would be mean numbers and percentages.

2. It is also helpful to add in variation of those ratios to Figure 3.

**********

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

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Submitted filename: Evocalcet head to head comparison with Cinacalcet .docx

Click here for additional data file.

21 May 2021

Journal Requirements:

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

Response: File names have been corrected accordingly.

2. We note that you have included the phrase “data not shown” in your manuscript. Unfortunately, this does not meet our data sharing requirements. PLOS does not permit references to inaccessible data. We require that authors provide all relevant data within the paper, Supporting Information files, or in an acceptable, public repository. Please add a citation to support this phrase or upload the data that corresponds with these findings to a stable repository (such as Figshare or Dryad) and provide and URLs, DOIs, or accession numbers that may be used to access these data. Or, if the data are not a core part of the research being presented in your study, we ask that you remove the phrase that refers to these data.

Response: These data are now included as Fig. 3.

3. Thank you for stating the following in the Competing Interests section: 'TS received consulting fees from Kyowa Kirin Co., Ltd. (KKC), Ono Pharmaceutical, Taisho Toyama Pharmaceutical, Fuji Pharma, and FUSO, and lecture fees from KKC, Chugai Pharmaceutical, Bayer, Kissei Pharmaceutical, Torii Pharmaceutical, Ono Pharmaceutical, and FUSO. SA, YE, and TK are employees of KKC. MF received consulting fees from KKC and Ono Pharmaceutical; lecture fees from KKC, Bayer, Torii Pharmaceutical, and Ono Pharmaceutical; and grants from KKC and Bayer. TA received consulting fees from KKC, Astellas Pharma, Bayer, Fuso Pharmaceutical, Japan Tobacco, Ono Pharmaceutical, Sanwa Chemical, Otsuka, GSK, and NIPRO, and lecture fees from KKC, Chugai Pharmaceutical, Bayer, Kissei Pharmaceutical, Torii Pharmaceutical, and Ono Pharmaceutical. The authors report no other conflicts of interest in this work.'

Please confirm that this does not alter your adherence to all PLOS ONE policies on sharing data and materials, by including the following statement: "This does not alter our adherence to PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors http://journals.plos.org/plosone/s/competing-interests). If there are restrictions on sharing of data and/or materials, please state these. Please note that we cannot proceed with consideration of your article until this information has been declared.

Response: As instructed, the updated Competing Interests Statement has been included in the cover letter.

Reviewer #1: Major comments

1. If I understand correctly the present analysis has been performed only in the patients of the evocalcet group of the parent head-to-head comparison study. This should be made clear from the outset. In the parent trial 320 patients were randomized to receive evocalcet. In the present ad hoc analysis only 253 patients were included. Why were the remaining 67 patients excluded ?

Response: In the previous phase 3 head-to-head comparison study [Fukagawa et al Kidney Int. 2018;94: 818–825] and this study (Line 149), the efficacy of evocalcet was evaluated in the per protocol set as primary analysis, which was defined as the population of patients included in the full analysis set, excluding the following: those who failed to meet any of the inclusion criteria, or patients who met any of the exclusion criteria; those with a drug compliance of <70% (based on patient reports to investigators at hospital visits); those who received a prohibited concomitant medication or therapy; those with missing iPTH levels at more than one of three time points in the evaluation period; and those with a protocol deviation that may have affected the efficacy evaluation. According to the previous phase 3 head-to-head comparison study, three patients discontinued the study before initiating the treatment and, therefore, 317 patients started the treatment with evocalcet. Of these, 253 were included in the per-protocol set. This information was included in the original article of the phase 3 head-to-head comparison study. To clarify the data source, the citation has been added in Line 177.

2. VDRA stands for calcitriol and a group of other active vitamin D compounds. Authors further need to tell from the outset which active vitamin D compounds were administered, and to which extent the administered doses were comparable.

Response: Specific active vitamin D compounds have been included in Line 112. A conversion method to show how their weekly doses were estimated has been included in Line 128.

3. Eighty-one patients among the 117 weekly zero VDRA dose patients were on oral VDRA therapy at baseline. Did they continue or was this therapy stopped at trial initiation ?

Response: As stated in Line 110, initiation of or changes in preparation, dose, and dosing regimen of VDRA medications or derivatives were not permitted from 2 weeks before screening until the end of the study in all patients, meaning that patients in the zero VDRA group continued the same oral VDRA therapy. The sentence in Line 111 has been changed to clarify that the above point applies to the IV and oral VDRA therapies.

4. In the Results section authors repeatedly mention « trends » for changes of various biochemistry values but actually fail to provide P values in the Figures or Figure legends. Therefore, I conclude that none of these « trends » corresponded to changes reaching the level of statistical significance. The terms « trend » and « trended » should be deleted and instead any non significant change should be acknowledged as no change. This will require a serrious revision of the interpretation of numerous results.

Response: The usage of “trend” and “dose-dependent difference” has been deleted. In addition, the lack of statistical analysis has been added as a limitation in Line 362.

5. Strictly speaking, hypocalcemia is not an ADR, all the more since the calcimimetic-induced decrease of serum PTH goes along with a decrease in serum calcium, at least in ESKD patients on dialysis therapy. It would be interesting to have information on usual hypocalcemia-associated clinical symptoms and signs.

Response: Although we understand the review comment, this was an ad hoc analysis of previously fixed data obtained in the head-to-head comparison study. As the reviewer pointed out, because of the clinical interest and significance of this study, future studies are needed to investigate the typical hypocalcemia-associated clinical symptoms and signs.

6. In a related post-hoc analysis of the EVOLVE trial in hemodialysis patients receiving cinacalcet therapy - not quoted by the authors - Floege et al found that in the majority of hypocalcemia episodes changes in calcium administration were the preferred treatment option (DOI: 10.1016/j.kint.2017.12.014). In that trial, adjustments of cinacalcet or vitamin D sterol doses were made only in a minority of hypocalcemia episodes. This observation, together with the observation in the present study that high-dose VDRA treatment was associated with significantly higher serum FGF23 levels than low-dose VDRA treatment, and the notion that higher FGF23 levels are associated with higher mortality risk, would rather plead against systematic VDRA administration in dialysis patients on calcimimetic therapy. The authors may want to make this clear in the Discussion.

Response: Accordingly, the discussion has been changed in Line 353, and the post-hoc analysis of the EVOLVE trial by Floege et al. has been added to the References section.

Minor remarks

Abstract should tell that evocalcet was administered orally. Moreover, authors need to indicate, both in Abstract and in Methods section, that the head-to-head comparison of the parent trial was between evocalcet and cinacalcet.

Response: The Abstract has been corrected by adding “oral” in Line 26. The Abstract and Materials and Methods sections have been corrected to clearly state that the previous phase 3 head-to-head comparison study investigated evocalcet and cinacalcet in Lines 24 and 89.

Abstract L37. I wonder whether the term « clinical benefits » is appropriate here, at least as far as FGF23 is concerned. As to the lesser incidence of hypocalcemia I would like to know whether concomitant vitamin D receptor activator treatment was more effective in avoiding hypocalcemia-associated symptoms and signs.

Response: “Clinical benefits” has been changed to “benefits” in Lines 39 and 374. All patients in the ad hoc analysis were treated with evocalcet and, therefore, further studies are needed to answer the reviewer’s comment.

Introduction. The statement that IV administration of VDRA « is the standard therapy for patients with SHPT » is incorrect as such. At least in the Western world VDRA can by given either orally or intravenously for the treatment of SHPT.

Response: Thank you for pointing this out; however, unlike Western countries, IV VDRA is the standard therapy for patients with SHPT and oral VDRA is used to supplement VD and/or treat hypocalcemia in Japan. To clarify the different application of oral VDRA, “in Japan” has been added in Line 57.

Discussion, lines 238-284. The statement is inappropriate that « intact PTH levels were slightly lower in the LDG and HDG compared with the NDG » since the difference was not statistically significant.

Response: The sentence “In this study, we found that over the 30 weeks of treatment, intact PTH levels were slightly lower in the LDG and HDG compared with the NDG” has been corrected to “Although it was not statistically significant, we found that over the 30 weeks of treatment, intact PTH levels tended to be slightly lower in the LDG and HDG compared with the NDG” in Line 303 to emphasize that it was not statistically significant.

Reviewer #2:

This study has demonstrated that the association of oral evocalcet with vitamin D activator was beneficial, with lower synthesis of FGF-23, lower incidence of hypocalcemia and with more patients achieving the calcium target. This oral formulation of evocalcet, was also associated with a reduction of gastric symptoms when compared with oral cinacalcet.

This study confirms the benefit of the treatment of hyperparathyroidism with an association of a calcimimetic + vitamin D.

The reduction of gastric symptoms verified with evocalcet will contribute for a better adherence of this new oral treatment for hyperparathyroidism.

However, the intravenous administration of etelcalcetide after hemodialysis, assures the patient adherence to this kind of treatment.

Evocalcet will be very useful for the treatment of patients with hyperparathyroidism who develop gastric symptoms associated with cinacalcet and who have no conditions for a three times/week intravenous treatment. This will be the case, for instance, of DP patients.

Response: We appreciate the reviewer’s comments on etelcalcetide and its comparison with evocalcet regarding its adherence and applications. Both drugs have advantages and disadvantages that can be used to provide the best available treatment according to each patient’s clinical characteristics and needs. In the previous head-to-head comparison study, the efficacy and safety of oral cinacalcet and evocalcet were compared and, therefore, we would like to keep the discussions on the comparisons between these two oral calcimimetics in this study.

Reviewer #3: This paper reported an ad-hoc analysis results using patients enrolled in one treatment arm of a completed phase III trial. Patients were categorized into three groups according to average weekly VDRA dose. Many clinical outcomes and adverse drug reactions were compared among these three groups. However, almost all statistical analysis only employed basic statistical tests and multiple testing adjustment was not implemented. In addition, most statements about the dose effect of VDRA were without rigorous statistical evidences presented. A professional statistician is recommended to be involved for rigorous data analysis and drawing conclusions.

Specifically,

1. Figure 1 displayed longitudinal mean measurements for each group of patients. It would be helpful to also include variations in the plots. In addition, linear mixed models are recommended to do a formal comparison among three patients groups and make conclusions rather than just looking at the plots and stating there was a tendency of VDRA dose-dependent trend.

Response: Standard deviations have been summarized in S2 Table. We appreciate the reviewer’s comment regarding the statistical analysis. The original phase 3 study, as well as this ad hoc analysis, was designed to statistically test the guideline target achievement rate among the treatment groups for mineral and bone disorder parameters, but not to test significant longitudinal trends in the repeated measures within each group or those among the groups. We are aware that a linear mixed model is a useful statistical tool whereby 30 weeks of measurements can be tested among the three groups unlike ANOVA. We will consider the reviewer’s comment when we design future studies. Please see our response to reviewer 1 comment 4 regarding the lack of statistical analyses on the VDRA dose-dependent trends.

2. Table 1 implies that these three groups of patients were not balanced in all baseline measurements. Therefore, the corresponding result comparisons should consider adjusting for these possible confounding factors.

Response: As the reviewer pointed out, we considered adjusting the outcome data with confounding factors, such as age, and baseline FGF23 and BAP levels. However, because of the small sample size (n=45 in the LDG group) it was impossible to adjust for such factors. Therefore, we have stated the potential for bias in Line 353.

3. A conclusion from Figure 4 says "The slope of the FGF23 intact and C-terminal relationship increased after treatment with evocalcet at Week 30 compared with Week 0 in all patients, as well as by VDRA DG." First, the estimated slope were not reported. Second, a formal statistical analysis should be implemented here to provide support of such statement.

Response: The estimated slopes for Week 0 and Week 30 in all patients, and those in three DGs, have been added to Fig. 4 (now changed to Fig. 5 after revision). The statistical analysis plan was created and approved for this study and, therefore, it is difficult to run an additional statistical analysis. Furthermore, because of the small sample size, we planned to find and discuss any tendency rather than statistical significances in this study.

Minor comments:

1. The title of Table 2 says "Mean numbers and percentages...". However, outcomes in Table 2 are all binary ones. It is confusing why there would be mean numbers and percentages.

Response: “Mean” has been deleted.

2. It is also helpful to add in variation of those ratios to Figure 3.

Response: Error bars have been added to Fig. 3 (now changed to Fig. 4 after revision).

Submitted filename: Response to Reviewers.docx

Click here for additional data file.

24 Jun 2021

PONE-D-21-07286R1

Evocalcet with vitamin D receptor activator treatment for secondary hyperparathyroidism

PLOS ONE

Dear Dr. Shigematsu

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

We look forward to receiving your revised manuscript.

Kind regards,

Pasqual Barretti, Ph.D., MD

Academic Editor

PLOS ONE

Additional Editor Comments (if provided):

The questions on statistical aspects from the reviewer 3 ara relevant and need to be address.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

Reviewer #3: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #3: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #3: No

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #3: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #3: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have provided satisfactory answers to all my queries and modified the manuscript as appropriate.

Reviewer #3: Previous comments related to rigorous statistical analysis were not fully addressed and hence this manuscript still does not reach the standard for publication. Authors are expected to fully address previous statistical comments again.

This is a post ad hoc analysis, so it is not convincible that no additional statistical analysis could be added because of a previously approved statistical analysis plan which is not submitted with this manuscript at all. There is one group of patients having relatively low number of patients (N=45), however, this sample size is not too small to adjust for any covariate. In addition, for a rigorous inference following any statistical analysis, 95% CI should be reported along with point estimate all the time. For example, the estimated slopes reported in Figure 5 should be reported along with the corresponding 95% CI.

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Reviewer #1: No

Reviewer #3: No

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13 Oct 2021

Below are our point-by-point responses to all the reviewers’ comments.

Reviewer #3: Previous comments related to rigorous statistical analysis were not fully addressed and hence this manuscript still does not reach the standard for publication. Authors are expected to fully address previous statistical comments again.

Response: We have addressed all previous statistical comments. Please see our responses below.

This is a post ad hoc analysis, so it is not convincible that no additional statistical analysis could be added because of a previously approved statistical analysis plan which is not submitted with this manuscript at all. There is one group of patients having relatively low number of patients (N=45), however, this sample size is not too small to adjust for any covariate. In addition, for a rigorous inference following any statistical analysis, 95% CI should be reported along with point estimate all the time. For example, the estimated slopes reported in Figure 5 should be reported along with the corresponding 95% CI.

Response: Please see our response to the third comment below.

Previous statistical comments

1. Figure 1 displayed longitudinal mean measurements for each group of patients. It would be helpful to also include variations in the plots. In addition, linear mixed models are recommended to do a formal comparison among three patients groups and make conclusions rather than just looking at the plots and stating there was a tendency of VDRA dose-dependent trend.

Response: Differences in changes in intact PTH, and corrected calcium and phosphorus from baseline to Week 30 among the three treatment groups were analyzed with a repeated linear mixed model, as suggested. As you will find in the Results section on pages 12–13, significant differences in the intact PTH, cCa, and phosphorus levels were found between certain groups. However, no significant difference was observed for the intact PTH, cCa, or phosphorus level among the three dose groups when the levels were adjusted according to their respective baseline levels (all cases p > 0.95). These results therefore suggest that evocalcet exerts its effect regardless of VDRA use or its dose.

2. Table 1 implies that these three groups of patients were not balanced in all baseline measurements. Therefore, the corresponding result comparisons should consider adjusting for these possible confounding factors.

Response: We have added the between-group differences of the target parameter achievement rates adjusted for age (< 65 and ≥ 65 years), sex, and intact PTH level (< 500 pg/mL and ≥ 500 pg/mL) at baseline and previous cinacalcet treatment to Table 2.

3. A conclusion from Figure 4 says "The slope of the FGF23 intact and C-terminal relationship increased after treatment with evocalcet at Week 30 compared with Week 0 in all patients, as well as by VDRA DG." First, the estimated slope were not reported. Second, a formal statistical analysis should be implemented here to provide support of such statement.

Response: As suggested by the reviewer, changes in the ratio of intact-to-C-terminal FGF23 between Week 0 and Week 30 were analyzed with a generalized linear mixed model. As shown below, the slope of the FGF23 intact and C-terminal relationship increased after treatment with evocalcet at Week 30 compared with Week 0 in all patients (p = 0.0002) and patients in the NDG (p = 0.0005). These results suggest a reduction in FGF23 synthesis. Although no statistical significance was observed, the slopes tended to increase in the LDG (p = 0.0696) and HDG (p = 0.0741). Results of the statistical analysis have been included in the Results section on page 19.

Submitted filename: Response to Reviewers comments.doc

Click here for additional data file.

6 Jan 2022

Evocalcet with vitamin D receptor activator treatment for secondary hyperparathyroidism

PONE-D-21-07286R2

Dear Dr. SHIGEMATSU

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Pasqual Barretti, Ph.D., MD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Actually, all of the invited reviewer in different steps of this revision process, have decided to accept the manuscript. In my opinion the manuscript has improved since its original submission. Therefore, may decision is " accept"

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #3: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #3: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #3: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #3: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #3: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #3: This time I agree that all my previous comments are fully addressed. So I recommend to accept it now.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #3: No