Treatment of relapsed/refractory (R/R) Hodgkin lymphoma (HL) following failure of brentuximab vedotin (BV) and PD-1 blockade is a major unmet need. Resistance to BV is associated with multidrug resistance gene 1 (MDR1) overexpression. MDR1 inhibitors cyclosporine (CsA) or verapamil (VRP) can re-sensitize cHL to BV. We previously reported preliminary results of a phase I study of BV combined with CsA in R/R HL. Here we report the final results of the completed study.
This is a single center, open-label phase I study. The dose finding portion followed a 3+3 design with 4 planned dose levels (DL). BV was given at 1.2 mg/kg (DL1) or 1.8 mg/kg (DL2-4) intravenously every 3 weeks. Planned dose of CsA was 5 mg/kg (DL1-2) or 7.5 mg/kg (DL3-4) orally twice daily on days 1-5. Planned dose of VRP was 120 mg orally four times daily on days 1-5 (DL4). Each cycle was 3 weeks. Once the maximum tolerated dose (MTD) was determined, BV-refractory pts were enrolled in an expansion cohort at the MTD. Primary objective was to determine the MTD and safety of the combination. Secondary objectives were overall response rate (ORR), complete response (CR) rate, response duration (DOR), overall survival (OS), and progression-free survival (PFS). 29 pts (14 dose-finding, 15 dose-expansion) were enrolled. Median age was 36 (20-69) and pts had a median of 5 (3-12) prior lines of therapy. All had prior BV (only 2 BV-sensitive) and 27 had prior PD-1 blockade. Four pts were treated on DL1, 22 on DL2, 3 on DL3. MTD was DL2. DLTs observed were: DL1 10-day CsA (n=1) grade (Gr) 3 hyperbilirubinemia, abdominal pain, and hypertension, DL2 (n=1) Gr3 abdominal pain and Gr3-4 neutropenia, DL3 (n=2) Gr3 bone pain/constipation/Gr4 lymphopenia (n=1) and Gr3 hyperglycemia (n=1). Median duration of treatment was 3 (1-16) cycles. Most frequent adverse events (AEs) were nausea (90%), hypertension (90%), anemia (86%), fatigue (76%), neutropenia (76%), and leukopenia (76%). All pts had Gr3+ AEs with most frequent being neutropenia (62%). Reasons for treatment discontinuation included death (n=4), disease progression (n=10), and toxicity (n=2). Treatment-related death occurred in 3 pts (pneumonitis at DL1, respiratory failure and hypotension at DL2). The ORR/CR was 62%/24%. The median DOR and PFS was 5 months and median OS was not reached.
BV + CsA was effective in BV-refractory R/R HL but was also associated with toxicity leading to early study termination.