Phase I/II study of erlotinib and temsirolimus for patients with recurrent malignant gliomas (MG) (NABTC 04–02)

2004 Background: Glioblastomas (GBM) frequently have EGFR amplification/mutations and inactivation of PTEN. Although single agent EGFR and mTOR inhibitors have limited activity, combinations of these agents may be more effective. Methods: The North American Brain Tumor Consortium conducted a phase I/II study of the EGFR inhibitor erlotinib in combination with the mTOR inhibitor temsirolimus in recurrent MG. Eligibility criteria were histologically proven GBM and anaplastic gliomas (AG), radiologic progression, >18 years old, KPS >60, adequate bone marrow and organ function. There was no limit on the number of prior relapses for phase I and no more than two prior relapses for phase II. Patients must not be receiving enzyme-inducing antiepileptic drugs. The dose of erlotinib was 150 mg/d in phase I and titrated up to maximum of 200mg/d in phase II depending on tolerability. Patients initially received temsirolimus 50 mg i.v. once weekly and the dose adjusted based on toxicities. Escalation was performed in groups of three. MTD was defined as the dose with 1/6 or fewer patients with dose-limiting toxicities (DLTs). Primary endpoint for the phase II component was PFS6. Results: In phase I, 22 patients were enrolled (15 GBM; 7 AG). Median age was 54 years (26–74); median KPS 90 (70–100); median prior relapses 1 (0–3). The MTD was determined to be 150 mg of erlotinib daily combined with 15 mg of temsirolimus weekly. DLTs were rash, mucositis, and liver function abnormalities. Pharmacokinetic data were similar to that for single agent erlotinib and temsirolimus; there was no interaction between the two drugs. AUC accumulation ratios between cycle 1 and 2 for erlotinib and OSI-420 were 3.6 and 4.6, respectively. In phase II, there were 56 patients (including 12 phase I patients treated at the MTD): 40 GBM; 16 AG, median age 47 years (20–72); median KPS 90 (range 60–100), median prior relapses 1 (range 1–3). Six patients discontinued therapy as a result of toxicities. For GBM patients, there was no PR, 30% SD, and PFS6 was 12.5%. For AG patients there was 12.5% PR, 12.5% SD, and PFS6 was 6.25%. Conclusions: The combination of erlotinib and temsirolimus was associated with a higher than expected incidence of toxicities and had minimal activity in recurrent MG. [Table: see text]