Abstract CT071: Continuous i.v. Crotoxin in advanced cancer: Intra-patient dose escalation

Abstract

Abstract Introduction: Crotoxin (CRTX), a potent neurotoxin from the venom of Crotalus durissus terrificus, rattlesnake, upon intramuscular administration has been shown to have broad anti-tumor activity accompanied with significant toxicity. Preclinical animal data suggested that in intra-patient dose escalation protocol the administration of high doses and efficacy can be achieved without toxicity. Methods: We followed the design of Medioni et al (Contemp. Clinical Trials Comm. 7, 2017: 186-168) in intra-patient dose escalation study to administer CRTX in heavily pre-treated patients (5 males and 1 female) with advanced solid tumors: 1 nasal squamous cell carcinoma, 2 glioblastomas, 1 endometrial adenocarcinoma, 1 NSCLC and 1 prostatic carcinoma. Lightweight RythmicTM pump capable of continuous delivery (no weekend breaks) allowed patients to stay at home. Over 35 days, CRTX dose escalation from 0.08 to 0.64 mg/m2/day was carried on Mondays, Wednesdays and Fridays, followed each time by 2h observation at the clinic. Dose limiting toxicity (DLT) and maximum tolerated dose (MTD) were defined as the inability of dose escalation twice due to toxicity and the dose at which no further dose escalation can be safely achieved for >33% of the pts in the study, respectively. Results: 2/6 patients developed possibly drug-related G1 diplopia and 1/6 pts increased ASAT/ALAT. One patient recruited with pre-existent diarrhoea syndrome with uncontrolled G2 hypomagnesaemia, G3 hypokalaemia and G2 anaemia, developed complete arrhythmia with asymptomatic atrial fibrillation that resolved with amiodarone. Patient was hospitalised for observation and the event was classified as a possible study drug-related SAE as well as related to the digestive syndrome and tubulopathy resulting from previous chemotherapy (nivolumab and platinum salts). Stable disease was observed in 2/6 patients. Conclusion: No DLT or MTD have been reached. CRTX dose escalation is safe but too slow, doses achieved too low and too late for advanced patients. In a new cohort, CRTX regimen will be continued starting from higher dose with faster dose escalation. Citation Format: Marian Gil Delgado, Gougis Paul, Dorothy H. Bray, Francois M. DELGADO, Jean P. SPANO, Ahmed Idbaih, Paul F. Reid, Khadija Benlhassan, Cheikh Diaw, David Khayat. Continuous i.v. Crotoxin in advanced cancer: Intra-patient dose escalation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT071.