Susan Boulton

A pilot study: 131I-Antitenascin monoclonal antibody 81c6 to deliver a 44-Gy resection cavity boost

The purpose of this study was to determine the feasibility and assess the efficacy and toxicity, among newly diagnosed malignant glioma patients, of administering (131)I-labeled murine antitenascin monoclonal antibody 81C6 ((131)I-81C6) into a surgically created resection cavity (SCRC) to achieve a patient-specific, 44-Gy boost to the 2-cm SCRC margin. A radioactivity dose of (131)I-81C6 calculated to achieve a 44-Gy boost to the SCRC was administered, followed by conventional external beam radiotherapy (XRT) and chemotherapy. Twenty-one patients were enrolled in the study: 16 with glioblastoma multiforme (GBM) and 5 with anaplastic astrocytoma. Twenty patients received the targeted 44-Gy boost (+/-10%) to the SCRC. Attributable toxicity was mild and limited to reversible grade 3 neutropenia or thrombocytopenia (n = 3; 14%), CNS wound infections (n = 3; 14%), and headache (n = 2; 10%). With a median follow-up of 151 weeks, median overall survival times for all patients and those with GBM are 96.6 and 90.6 weeks, respectively; 87% of GBM patients are alive at 1 year. It is feasible to consistently achieve a 44-Gy boost dose to the SCRC margin with patient-specific dosing of (131)I-81C6. Our study regimen ((131)I-81C6 + XRT + temozolomide) was well tolerated and had encouraging survival. To determine if selection of good-prognosis patients affects outcome associated with this approach, the U.S. Food and Drug Administration has approved a trial randomizing newly diagnosed GBM patients to either our study regimen or standard XRT plus temozolomide.

Bevacizumab continuation beyond initial bevacizumab progression among recurrent glioblastoma patients

Background:Bevacizumab improves outcome for most recurrent glioblastoma patients, but the duration of benefit is limited and survival after initial bevacizumab progression is poor. We evaluated bevacizumab continuation beyond initial progression among recurrent glioblastoma patients as it is a common, yet unsupported practice in some countries.Methods:We analysed outcome among all patients (n=99) who received subsequent therapy after progression on one of five consecutive, single-arm, phase II clinical trials evaluating bevacizumab regimens for recurrent glioblastoma. Of note, the five trials contained similar eligibility, treatment and assessment criteria, and achieved comparable outcome.Results:The median overall survival (OS) and OS at 6 months for patients who continued bevacizumab therapy (n=55) were 5.9 months (95% confidence interval (CI): 4.4, 7.6) and 49.2% (95% CI: 35.2, 61.8), compared with 4.0 months (95% CI: 2.1, 5.4) and 29.5% (95% CI: 17.0, 43.2) for patients treated with a non-bevacizumab regimen (n=44; P=0.014). Bevacizumab continuation was an independent predictor of improved OS (hazard ratio=0.64; P=0.04).Conclusion:The results of our retrospective pooled analysis suggest that bevacizumab continuation beyond initial progression modestly improves survival compared with available non-bevacizumab therapy for recurrent glioblastoma patients require evaluation in an appropriately randomised, prospective trial.

Molecular Targets for Antibody-Mediated Immunotherapy of Malignant Glioma

Despite advances in surgical and radiation therapy over the past two decades, the prognosis for many brain -tumor patients remains dismal. Novel antibody-mediated immunotherapeutics are emerging in the next generation of targeted therapeutic drugs for cancer treatment, and at least nine have been approved by the FDA to date. In this chapter we review the identification and validation of appropriate CNS tumor-associated antigens and the current status of antibody-mediated therapies under development and those that are already showing encouraging promise in the clinical setting.

Abstract CT416: Intratumoral administration of an Oncolytic Polio/Rhinovirus Recombinant (PVSRIPO) in recurrent glioblastoma (GBM): Preliminary results of the Phase I clinical trial

Background: PVSRIPO is the live attenuated, oral (SABIN) serotype 1 poliovirus vaccine containing a heterologous internal ribosomal entry site stemming from human rhinovirus type 2. An oncofetal cell adhesion molecule and tumor antigen widely expressed ectopically in malignancy, nectin-like molecule-5, is recognized by PVSRIPO. We report the preliminary results of a phase I clinical trial evaluating the intratumoral administration via convection-enhanced delivery (CED) of PVSRIPO. Methods: Eligibility criteria for adult patients included: recurrent supratentorial GBM; 1-5 cm in diameter; ≥1cm away from the ventricles; ≥4 weeks after chemotherapy, bevacizumab (BEV) or study drug; adequate organ function; KPS >70%; and positive anti-poliovirus titer. Dose was rapidly escalated using a two-step continual reassessment method with anticipated accrual of 1 patient each on dose levels 1-4, and up to 21 patients at dose level 5. Results: Thus far, ten patients have been treated (1 each at levels 1 and 3, 2 at level 2, 2 at level 4, 4 at level 5). One dose limiting toxicity (patient #8) was observed at level 5, a grade 4 intracranial hemorrhage at the time of catheter removal, which required de-escalation to level 4. Grade 3 adverse events possibly related to study include hemiparesis (n=1) and lymphopenia (n=1). No grade 5 study related adverse events were observed. Eight patients remain alive, with two patients now 20 and 19 months post PVSRIPO, respectively. Two patients having previously failed BEV died six months post-infusion after initiating hospice care due to persistence of baseline neurologic deficits. After observing prolonged steroid use in 5 of 7 patients treated on dose levels 3 to 5 and after results of new immunogenic analysis became available, it was agreed upon that dose level 2 is probably the optimal dose level. The study has been amended to treat a total of 6 patients at dose level 2. Conclusion: Infusion of PVSRIPO via CED in the clinical setting is safe thus far and observed efficacy outcomes are intriguing. Dose expansion at dose level 2 is ongoing. Citation Format: Annick Desjardins, J H. Sampson, K B. Peters, T Ranjan, G Vlahovic, S Threatt, J E. Herndon, S Boulton, D Lally-Goss, F McSherry, A Friedman, H S. Friedman, D D. Bigner, M Gromeier. Intratumoral administration of an Oncolytic Polio/Rhinovirus Recombinant (PVSRIPO) in recurrent glioblastoma (GBM): Preliminary results of the Phase I clinical trial. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT416. doi:10.1158/1538-7445.AM2014-CT416