Clinical activity, safety, and biomarkers of MPDL3280A, an engineered PD-L1 antibody in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC).

Abstract

8008Background: Human lung cancer expresses high levels of PD-L1, which may inhibit anti-cancer immune responses. MPDL3280A, a human monoclonal Ab containing an engineered Fc-domain designed to optimize efficacy and safety, targets PD-L1, blocking PD-L1 from binding its receptors, including PD-1 and B7.1. Methods: Pts with squamous or nonsquamous NSCLC received MPDL3280A IV q3w at doses between 1-20 mg/kg in a Ph I expansion study. Pts were treated for up to 1 y. Objective response rate (ORR) was assessed by RECIST v1.1. Reported ORR includes u/cCR and u/cPR. Results: As of Jan 10, 2013, 53 NSCLC pts were evaluable for safety and treated at doses of ≤1 (n=2), 10 (n=10), 15 (n=19) and 20 mg/kg (n=22). Pts had a median age of 61 y (range 24-83 y), 98% were PS 0-1, 89% had prior surgery and 55% had prior radiotherapy. 98% of pts received prior systemic therapy. Pts received treatment for a median duration of 106 days (range 1-324) of MPDL3280A. The incidence of all G3/4 AEs, regardless of attribution, was 34%, including pericardial effusion (6%), dehydration (4%), dyspnea (4%) and fatigue (4%). No G3-5 pneumonitis or diarrhea was reported. 37 NSCLC pts enrolled prior to Jul 1, 2012, were evaluable for efficacy. RECIST responses were observed at dose levels between 1 and 20 mg/kg, with all responses ongoing or improving. An ORR of 24% (9/37) was observed in pts with squamous and nonsquamous histologies, including several with rapid tumor shrinkage. Additional pts had delayed responses after apparent radiographic progression (not included in the ORR). The 24-week PFS was 48%. Analysis of biomarker data from archival tumor samples demonstrated a correlation between PD-L1 status and efficacy. Pts who were PD-L1 tumor status–positive showed an ORR of 100% (4/4) and a PD rate of 0% (0/4), while pts who were PD-L1 tumor status–negative showed an ORR of 15% (4/26) and a PD rate of 58% (15/26). Updated data will be presented. Conclusions: Treatment with MPDL3280A was well tolerated, with no pneumonitis-related deaths. Rapid and durable responses were observed. PD-L1 tumor status correlated with response to MPDL3280A. Clinical trial information: NCT01375842.