INTRODUCTION: Paclitaxel, a microtubule binding agent with potent anti-glioma activity in vitro, exhibits poor penetrance to the CNS when delivered systemically. To minimize toxicity and reach therapeutic concentrations in the CNS, paclitaxel was previously incorporated into biodegradable microspheres (Paclimer), and the efficacy of Paclimer was determined in a rat model of malignant glioma. In this study we report the safety of intracranial Paclimer in a canine dose escalation toxicity study to prepare its translation into clinical scenarios. METHODS: Twelve normal beagle dogs underwent a right parieto-occipital craniectomy and were randomized to receive either Paclimer at 2-mg/kg (n=5), empty microspheres at 2-mg/kg (n=1), Paclimer at 20-mg/kg (n=5), or empty microspheres at 20-mg/kg (n=1). Post-operatively, dogs were observed daily for signs of neurotoxicity. Complete blood counts and plasma levels of paclitaxel were obtained weekly. CSF levels and MRI scans were obtained on days 14-120. Paclitaxel concentrations were quantified by LC-MS. RESULTS: Animals treated with 20-mg/kg Paclimer had minimal paclitaxel levels in plasma (range 0-7.84 ng/ml) and CSF (range 0-1.16 ng/ml). Animals treated with 2 mg/kg Paclimer had undetectable levels of paclitaxel in plasma, CSF was not obtained to minimize animal suffering. All animals exhibited normal behavior and weight gain, and were alive post-operatively through the last day of the study (day 60-120) without signs of neurological toxicity. There was no evidence of systemic toxicity or myelosuppression. MR imaging was comparable between Paclimer animals and controls. Adverse effects included wound infections and a brain abscess, all of which responded to antibiotic therapy, and one ventriculomegaly due to communicating hydrocephalus. CONCLUSIONS: Paclimer-based delivery of paclitaxel is safe for intraparenchymal delivery at the tested doses in normal dogs.
INTRODUCTION:Paclitaxel, a microtubule binding agent with potent anti-glioma activity in vitro, exhibits poor penetrance to the CNS when delivered systemically. To minimize toxicity and reach therapeutic concentrations in the CNS, paclitaxel was previously incorporated into biodegradable microspheres (Paclimer), and the efficacy of Paclimer was determined in a rat model of malignant glioma. In this study we report the safety of intracranial Paclimer in a canine dose escalation toxicity study to prepare its translation into clinical scenarios. METHODS: Twelve normal beagle dogs underwent a right parieto-occipital craniectomy and were randomized to receive either Paclimer at 2-mg/kg (n=5), empty microspheres at 2-mg/kg (n=1), Paclimer at 20-mg/kg (n=5), or empty microspheres at 20-mg/kg (n=1). Post-operatively, dogs were observed daily for signs of neurotoxicity. Complete blood counts and plasma levels of paclitaxel were obtained weekly. CSF levels and MRI scans were obtained on days 14-120. Paclitaxel concentrations were quantified by LC-MS. RESULTS: Animals treated with 20-mg/kg Paclimer had minimal paclitaxel levels in plasma (range 0-7.84 ng/ml) and CSF (range 0-1.16 ng/ml). Animals treated with 2 mg/kg Paclimer had undetectable levels of paclitaxel in plasma, CSF was not obtained to minimize animal suffering. All animals exhibited normal behavior and weight gain, and were alive post-operatively through the last day of the study (day 60-120) without signs of neurological toxicity. There was no evidence of systemic toxicity or myelosuppression. MR imaging was comparable between Paclimer animals and controls. Adverse effects included wound infections and a brain abscess, all of which responded to antibiotic therapy, and one ventriculomegaly due to communicating hydrocephalus. CONCLUSIONS: Paclimer-based delivery of paclitaxel is safe for intraparenchymal delivery at the tested doses in normal dogs.
Authors: M R Fetell; S A Grossman; J D Fisher; B Erlanger; E Rowinsky; J Stockel; S Piantadosi Journal: J Clin Oncol Date: 1997-09 Impact factor: 44.544
Authors: S Valtonen; U Timonen; P Toivanen; H Kalimo; L Kivipelto; O Heiskanen; G Unsgaard; T Kuurne Journal: Neurosurgery Date: 1997-07 Impact factor: 4.654
Authors: K A Walter; M A Cahan; A Gur; B Tyler; J Hilton; O M Colvin; P C Burger; A Domb; H Brem Journal: Cancer Res Date: 1994-04-15 Impact factor: 12.701
Authors: Carlos Delfino; Graciela Caccia; Luis Riva Gonzáles; Elizabeth Mickiewicz; Jeannette Rodger; Luis Balbiani; Daniel Flores Morales; Alberto Zori Comba; Celia Brosio Journal: Oncology Date: 2004 Impact factor: 2.935
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Authors: Betty M Tyler; Alia Hdeib; Justin Caplan; Federico G Legnani; Kirk D Fowers; Henry Brem; George Jallo; Gustavo Pradilla Journal: J Neurosurg Spine Date: 2012-01
Authors: Ananth K Vellimana; Violette Renard Recinos; Lee Hwang; Kirk D Fowers; Khan W Li; Yonggang Zhang; Saint Okonma; Charles G Eberhart; Henry Brem; Betty M Tyler Journal: J Neurooncol Date: 2012-12-07 Impact factor: 4.130