PRELIMINARY ACTIVITY OF DEVIMISTAT (CPI 613) IN PATIENTS WITH RELAPSED OR REFRACTORY BURKITT LYMPHOMA/LEUKEMIA

Abstract

Introduction: Patients (pts) with primary refractory or relapsed Burkitt lymphoma/leukemia (BL) or high-grade B-cell lymphoma with MYC and BCL2 rearrangements (double hit, DHL) and/or BCL6 (triple hit, THL) have a dismal prognosis. A dysregulated MYC oncogene has downstream effects on proliferation and highly glycolytic metabolism with tricarboxylic acid (TCA) cycle intermediates as biosynthetic precursors. Devimistat is a non-redox active analogue of lipoic acid, a required cofactor for two key TCA cycle mitochondrial enzymes: pyruvate dehydrogenase and alpha ketoglutarate dehydrogenase. Disruption results in a shutdown of ATP and biosyntheticintermediate production leading to cancer cell death. In a phase I trial (n = 26) a pt with multiply refractory BL had a partial remission sustained over one year prior to resection. She remains in remission 7 years later. As of March 2021, 20 clinical studies in over 700 pts with various cancers have been conducted (ongoing/completed) with devimistat. We initiated a phase II trial to further explore efficacy. Methods: NCT03793140 is a multicenter study enrolling 17 patients on each of two cohorts BL or DHL/THL. Pts must have had one prior therapy or are refusing standard of care, measurable disease or isolated bone marrow involvement, and must not be within 3 months of a prior stem cell transplant. Active central nervous system (CNS) parenchymal disease is excluded, but leptomeningeal disease is allowed if the CSF is negative for more than 4 weeks and the maintenance intrathecal/intraOmmaya therapy is ongoing. Devimistat is given by central line over 2 hours daily x 5 days for two 14-day cycles and then as maintenance every 21 days. Pts are evaluable for response if they receive at least 4/5 days of the first cycle. At least 1response in the first 9 pts by cycle 3 was needed to expand to 17 pts in total in that cohort. Results: 9 pts were enrolled in the DHL/THL arm. Number of prior therapies was 3(1-6). No responses and only 1 stable disease resulted in cohort closure. Thus far, 8 BL pts were enrolled. Number of prior therapies was 3 (2-4). 2 pts were inevaluable. 1/6 pts had a response. This HIV+ pt had a thigh mass having received 4 prior therapies. He had a near complete metabolic remission after 3 cycles of devimistat. PET/CT assessment: Thigh lesion baseline October 19, 2020: 10.8 x 6.5 cm SUV 24. After cycle 3: unmeasurable, SUV 2. He is currently in cycle 7, having had a 4-week treatment delay of cycle 5 due to CoVID 19 infection. ECOG improved from 3 to 0. Adverse events (AE): As of March 03, 2021, no serious AEs related to study drug. 4 pts had grade 3 events at least possibly related: 2 neutropenia, 1 thrombocytopenia and 1 elevated bilirubin. 1 patient had a dose reduction for grade 2 alanine aminotransferase increase. Conclusions: Although our results are preliminary, the near complete remission in this patient is promising in a disease where no viable treatment options exist.