Polatuzumab vedotin (Pola) + obinutuzumab (G) and lenalidomide (Len) in patients (pts) with relapsed/refractory (R/R) follicular lymphoma (FL): Interim analysis of a phase Ib/II trial.

Abstract

7505 Background: Pola-G-Len may enhance anti-tumor immune response in R/R FL. We report a pre-planned interim analysis of the safety/efficacy of induction and maintenance with Pola-G-Len in pts with R/R FL in a phase Ib/II study. Methods: Pts received induction treatment with 6x 28-D cycles of: G 1000mg IV (C1: D1, D8, D15; C2–6: D1); Pola 1.4mg/kg or 1.8mg/kg (dose escalation [DE]) or RP2D (expansion) IV (D1); and Len 10–20mg (DE) or RP2D (expansion) PO (D1–21). Pts with CR/PR/SD at the end of induction (EOI) received G 1000mg (D1 every 2mo, for 24mo), and Len (10mg, D1–21 monthly, 12mo). Primary endpoints: C1 DLTs, safety/tolerability, CR rate at EOI (modified Lugano criteria). Results: At the interim data cut-off (7/6/2018), 52 pts were enrolled: 9 discontinued the study (adverse events [AE], n=3; death due to PD, n=4; pt withdrawal, n=1; other, n=1). Median pt age was 62 (range 32–87) years; 58% FLIPI 3–5; 79% ≥2 prior therapy lines; 50% refractory to last treatment. Grade ≥3 AEs were experienced by 75% of pts: neutropenia (46%), thrombocytopenia (17%), anemia (12%) and infections (12%) were most common. AEs leading to Len dose reduction/interruption occurred in 31%/52% of pts. One Grade 5 AE was reported (septic shock after PD in pt receiving subsequent therapy). RP2D: Pola 1.4mg/kg + Len 20mg. Preliminary efficacy data suggest high activity (Table). Median PFS not reached (median follow-up duration 8.95mo; efficacy-evaluable population [EEP]). Conclusions: The safety profile of Pola-G-Len is consistent with known profiles of the individual drugs. Response rates at EOI with Pola-G-Len are promising, with high CR compared with available R/R FL treatments. Responses at EOI (EEP; RP2D; N=18). Clinical trial information: NCT02600897. [Table: see text]