Faculty Bibliography

Background Activation of the mammalian target of rapamycin (mTOR) signaling pathway is thought to be a key driver of tumor growth in Merlin (NF2)-deficient tumors. Everolimus is an oral inhibitor of mTOR complex 1 (mTORC1) with antitumor activity in a variety of cancers. Methods We conducted a single-institution, prospective, 2-stage, open-label phase II study to estimate the response rate to everolimus in neurofibromatosis type 2 (NF2) patients with progressive vestibular schwannoma (VS). Ten eligible patients were enrolled, including 2 pediatric patients. Everolimus was administered at a daily dose of 10 mg (adults) or 5 mg/m(2)/day (children <18 y) orally in continuous 28-day courses, for up to 12 courses. Response was assessed every 3 months with MRI, using 3-dimensional volumetric tumor analysis, and audiograms. Nine patients were evaluable for the primary response, defined as >/=15% decrease in VS volume. Hearing response was evaluable as a secondary endpoint in 8 patients. Results None of the 9 patients with evaluable disease experienced a clinical or MRI response. No objective imaging or hearing responses were observed in stage 1 of the trial, and the study was closed according to predefined stopping rules. Conclusion Everolimus is ineffective for the treatment of progressive VS in NF2 patients. We are currently conducting a pharmacokinetic/pharmacodynamic ("phase 0") study of everolimus in presurgical VS patients to elucidate the biological basis for apparent treatment resistance to mTORC1 inhibition in these tumors.

The myeloproliferative neoplasm, myelofibrosis, is a morbid and frequently fatal illness encompassing primary myelofibrosis, and end-stage essential thrombocythemia and polycythemia. Bevacizumab (15 mg/kg intravenous (i.v.) every 21 days) was tested in a phase II international trial conducted by the Myeloproliferative Disorders Research Consortium. Thirteen patients were enrolled in the first stage of this 2-stage trial. Among the 11 patients who received therapy, only 3 received more than 4 cycles of therapy; none of the patients achieved an objective response. Furthermore, significant toxicity, not directly related to the vascular or gastrointestinal events typically associated with the anti-VEGF monoclonal antibody preparation in other disease states, was observed. Lack of objective responses coupled with toxicity led to the decision to terminate the study early. If future studies incorporate bevacizumab in combination therapy for myelofibrosis, more modest doses should be considered. (clinicaltrials.gov Identifier 00667277).

Objective: Irinotecan and bevacizumab have single-agent activity in both platinum- sensitive and -resistant recurrent ovarian cancer. We sought to evaluate the efficacy and safety of irinotecan in combination with bevacizumab in these patients. The primary end point of the study was to estimate the progression-free survival (PFS) rate at 6 months. Secondary objectives included overall survival, observed response rate, duration of response, and toxicity. Methods: Patients with recurrent ovarian cancerwho had received any number of prior regimens were eligible. Irinotecan 250 mg/m2 (amended to 175 mg/m2 after treatment-related toxicities in the first 6 patients) and bevacizumab 15 mg/kg every 3 weeks were administered until disease progression or toxicity. Response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) every 2 cycles and by CA-125 criteria for those patients without measurable disease. Results: Thus far, 25 of the planned 35 patients have been enrolled in the study. Themedian age was 61 years (range, 45-78 years). Seven patients were platinum-sensitive and 18 patients were platinum-resistant. The median number of prior regimens was 5 (range, 1-12), with 10 patients having received prior bevacizumab-containing therapies and 9 patients prior topotecan-containing therapies. The median number of study treatments received was 6 cycles (range, 1-25 cycles); 4 patients withdrew after only 1 cycle (3 due to toxicity and 1 due to physician discretion). Of the 19 patients assessable for response at this time, 5 patients experienced partial response (PR), 11 patientsmaintained stable disease (SD), and 3 patients had progressive disease. Eleven of the patients with PR/SD were platinum-resistant. The observed clinical benefit rate (PR+SD) was 68% (95% CI: 50%, 86%) for the 25 enrolled patients (intention to treat). Durable responses were observed, with 9 patients having longer than 24 weeks of sustained response. Themedian PFS was 8.1 months, and the median overall survival was!