Immunotherapy "Shock" a case series of PD-L1 100% and pembrolizumab first-line treatment.

In this decade a "bloom" of novel therapies has been observed for non-small cell lung cancer. We have new tools for the diagnosis of lung cancer and also we can re-biospy easier than before in different lesions and obtain tissue samples in order to investigate whether a patient can receive new targeted therapies. Immunotherapy has been well established previously for other forms of cancer, and nowadays it is also available for lung cancer. There are two immunotherapies for now nivolumab and pembrolizumab which can be administered as second line treatment, the second can also be administered as first-line if there is a programmed death-ligand 1 ≥50% expression.

Introduction

Lung cancer is still diagnosed at a late stage although we have new diagnostic tools in our everyday clinical practice. Regarding the imaging methods we have the positron emission tomography-cat scan (PET-CT) for diagnosis and staging of lung cancer [1]. Regarding interventional methods we have the radial endobronchial ultrasound and the convex-probe endobronchial ultrasound (EBUS) which we have again for the diagnosis and staging of lung cancer [2], [3]. In the past decade targeted therapy was added to our clinical practice with tyrosine kinase inhibitors (TKIs), and in the last year immunotherapy was added in our everyday clinical practice. Regarding immunotherapy we have nivolumab as second line treatment and pembrolizumab as first line treatment if we have ≥50% programmed death-ligand 1 (PD-L1) and as second line if we have ≥1% [4], [5]. There are different adverse effects between the targeted treatments and immunotherapy, in any case of course there are much less than the non-specific cytotoxic agents [6], [7]. In order to investigate the PD-L1 expression we use the PD-L1 IHC 22C3 pharmDx (DAKO) which was developed in partnership with the pharmaceutical company producing the pembrolizumab drug. Nowadays there also other kits that can identify the PD-L1 expression and are being tested. However; as it has been observed once again “tissue is the issue”, the tissue specimen has to be well prepared after biopsy and well preserved as it has been observed PD-L1 expression depends on the “slice” of the paraffin block. In the same tissue biopsy the expression might be low in a slice of the paraffin block, while in the next slice high.

Methods of programmed death-ligand 1 (PD-L1)

Immunohistochemistry for both antibodies was performed in 2-μm tissues on positive charged slides.

Programmed death-ligand 1 (PD-L1) [clone: CAL10 (RTU, CE, IVD), Biocare, CA, USA)

External positive controls were tonsil tissues placed on each slide. Immunohistochemistry was performed in Autostainer platform BOND Max™ (Leica Biosystems, Wetzlar, G). The antibody was in a ready-to-use form (RTU) and the incubation time was 20 minutes.

Programmed death-ligand 1 (PD-L1) PD-L1, 22C3 pharmDx™ Kit NSCLC. Companion diagnostic system Dako, Denmark,EU. This protocol is a complete automate stable procedure, performed in AutostainerLink48 Dako platform. Each staining run includes external positive cell line control.

Case 1

A 65 year old man was diagnosed with lung adenocarcinoma with fine needle biopsy 18G needle from a large mass on the right upper lobe (Fig. 1). Epidermal growth factor (EGFR) and anaplastic lymphoma kinase (ALK) mutations were negative. Programmed death-ligand 1 expression however was 100% with DAKO and 95% with the “BioCare” (Fig. 2, Fig. 3). The patient was stage IV with bone metastasis and it was decided that he receives pembrolizumab 200 mg. After four days of administration the patient presented fever ≥38 °C and dyspnea. In the emergency room he had saturation 70%SpO2 with FiO2 21%. Laboratory findings from its blood were White Blood Count (WBC): 10.16 K/μl, Hemoglobin (HGB): 11.5 g/dL, Platelets (PLT): 201 K/μL, C-reactive protein (CRP): 1.30 mg/dL, Procalcitonin (PCT): 0.3 ng/mL and Erythrocyte Sedimentation Rate (ESR): 5 mm. The rest of his laboratory findings were within normal rates, we focus on these values because we want to distinguish whether he had an abscess and infection or just an abscess. Indeed, a new CT of the thorax revealed that the lung mass had become an abscess (Fig. 1). The patient also started to cough large quantities of thick sputum. Oxygene and supportive therapy for his vitals were initiated. The patient remained in the intensive care unit (ICU) until he was stable and pembrolizumab was again initiated, he remains under treatment and follow-up with 200 mg.

Fig. 1

Left side the mass upon diagnosis and right side after 7 days of 200 mg pembrolizumab administration.

Fig. 2

BioCare: left side X 40 magnification, middle X 200 magnification and right side X 400 magnification.

Fig. 3

DAKO: x 10 magnification.

Case 2

A 55 year old man was diagnosed with lung adenocarcinoma with a Pentax convex-probe endobronchial ultrasound (EBUS) right hemithorax paratracheal (Fig. 4, Fig. 5, Fig. 6). The patient was stage IV with bone metastasis and he did not have EGFR or ALK mutations, however; he had programmed death-ligand 1 expression 100% with DAKO and 90% with BioCare (Fig. 7, Fig. 8). Pembrolizumab was initiated with 200 mg as it is indicated. Fever was observed ≥38 °C after 2 days the laboratory findings indicated a mild infection and therefore antibiotics were initiated. %. Laboratory findings from its blood were White Blood Count (WBC): 18.36 K/μl, Hemoglobin (HGB): 14 g/dL, Platelets (PLT): 250 K/μL, C-reactive protein (CRP): 8 mg/dL, Procalcitonin (PCT): 5 ng/mL and Erythrocyte Sedimentation Rate (ESR): 30 mm. However; based on our previous experience we performed a new CT of the thorax and it was observed that the primary lesion was an abscess, however; regional lymph nodes remained the same. Moreover a previous lesion on the left lung remained the same (24mm) (Fig. 4, Fig. 5, Fig. 6). Upon his new treatment appointment the patient (21 days after the initial administration) had normal laboratory values without fever and therefore it was decided again to administer pembrolizumab 200 mg. The patient is on follow-up. Elastography was performed to this patient and a strain ratio of 0.07% was identified. This finding suggests as an initial finding that the lesion was a malignancy, however; nothing more. Elastography cannot be used to predict the efficiency of a therapy.

Fig. 4

Left side the mass upon diagnosis and right side after 7 days of pembrolizumab 200 mg administration.

Fig. 5

Left side: lung metastasis of the left lung upon diagnosis and right side: the same lung metastasis of the left lung which did not change after the pembrolizumab administration.

Fig. 6

Elastography upon diagnosis with a strain ration of 0.07%.

Fig. 7

BioCare: left side X 10 magnification, middle: X 40 magnification, right side: X 400 magnification.

Fig. 8

DAKO: left side X 10 magnification, middle: X 40 magnification, right side: X 400 magnification.

Discussion

Certainly the adverse effects of immunotherapy are less than the standard chemotherapy [8], however; immunotherapy adverse effects are being investigated [5]. Pembrolizumab demonstrated efficiency in first-line treatment for patients with programmed death-ligand 1 expression ≥50% vs chemotherapy, however; the same results were not observed with nivolumab [9]. This observation was attributed to the different patient selection [10]. In the case of a patient with both EGFR mutation and PD-L1 ≥50% tkis are currently advised [11]. Tyrosine kinase inhibitors have few and well controlled adverse effects [12], [13], [14]. These adverse effects are also well controlled for thetkis administered for mutation T790M [15], [16]. The cases that we currently present are the first where PD-L1 = 100% with DAKO has been observed along with abscess which we attribute to the connection of pembrolizumab and the high expression of PD-L1. The adverse effects of immunotherapy have been previously well described, however; we have still many to observe [17], [18], [19], [20]. We have observed small differences between the Bio Care kit clone CAL10 and the 22C3 pharmDx™ Kit, DAKO expression. These small differences we attribute them to the different tissue specimen (slice from the paraffin block), however; definitely we need more tissue specimens and patients to have a clear view on this subject. Probably different lesions of the same patient have different PD-L1 expression, therefore we observe different efficacy of the therapy in different lesions. Caution should be taken for these patients with such PD-L1 expression.

Conflict of interest

None to declare.