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MO18 - NSCLC - Targeted Therapies IV (ID 116)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Track: Medical Oncology
- Presentations: 1
MO18.01 - An analysis of the relationship of clinical activity to baseline EGFR status, PD-L1 expression and prior treatment history in patients with non-small cell lung cancer (NSCLC) following PD-L1 blockade with MPDL3280A (anti-PDL1) (ID 2347)
16:15 - 17:45 | Author(s): R. Heist
NSCLC may utilize PD-L1 overexpression to escape immune surveillance. This mechanism has been suggested by recent clinical studies showing that NSCLC can respond to PD-L1/PD-1 blockade. MPDL3280A, a human monoclonal antibody containing an engineered Fc-domain designed to optimize efficacy and safety, aims to restore tumor-specific T-cell immunity by blocking PD-L1 from binding to its receptors, PD-1 and B7.1.
Patients received MPDL3280A IV q3w for up to 1 year in a Phase I dose escalation/expansion study. Objective response rate (ORR) was assessed by RECIST v1.1 and included unconfirmed/confirmed responses. EGFR and KRAS status was initially assessed locally by investigators. Archival tissue was analyzed centrally for PD-L1 expression by IHC.
As of Feb 1, 2013, 52 NSCLC patients were evaluable for safety and treated at doses of 0.03-20 mg/kg. The median age of patients was 61 years (range, 24-83). 17 (33%) of patients were ECOG PS 0 and 35 (67%) of patients were ECOG PS 1. Prior treatments included surgery (89%), radiotherapy (54%) and systemic therapy (98%). 15% of patients received 1 prior regimen, 21% received 2 and 62% received ≥3. Additionally, 14%, 62% and 25% of patients were EGFR-mutation positive, EGFR WT and EGFR status unknown/undetermined, respectively, and 12%, 40% and 48% of patients were KRAS-mutation positive, KRAS WT and KRAS status unknown/undetermined, respectively. Patients received treatment with MPDL3280A for a median duration of 106 days (range 1-450). Treatment-related Gr3/4 AEs occurred in 12% of patients, including fatigue (4%) and hypoxia (4%). 1 patient experienced a Gr3/4 immune-related AE (Gr3 hyperglycemia). No Gr3-5 pneumonitis or diarrhea was reported. 41 NSCLC patients first dosed at 1-20 mg/kg prior to Aug 1, 2012, were evaluable for efficacy. An ORR of 22% (9/41) was observed in patients (squamous [n=9]/nonsquamous [n=31]) with a duration of response range of 1+ to 214+ days. Additional patients had nonconventional responses after apparent radiographic progression but were considered to have progressive disease in this analysis. All responses were ongoing or improving at data cutoff. The 24-week PFS was 46%. ORR by patient characteristics was also examined. The ORR for patients with ≤2 prior therapies was 23% (4/17) and 23% (5/22) for patients with >2 prior therapies. Additionally, the response for former/current smokers was 23% (8/35) versus 17% (1/6) for never smokers. Between EGFR-mutation positive and EGFR WT patients, the ORRs also did not differ (25% [1/4] and 19% [5/26], respectively). In contrast, PD-L1 status was associated with ORR response as patients with PD-L1–positive tumors had an ORR of 80% (4/5) and patients with PD-L1–negative tumors had an ORR of 14% (4/28). Updated data, including responses by KRAS status, will be presented.
Treatment with MPDL3280A was generally well tolerated, with no cases of Gr3-5 pneumonitis. Rapid and durable responses were observed, including in an EGFR-mutation positive patient. Responses to MPDL3280A did not appear influenced by the number of prior treatment regimens but did appear to be associated with PD-L1 tumor status. Additional studies have been initiated in NSCLC.
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