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DOI: 10.1055/s-0037-1598277
Atezolizumab as first-line therapy (1L) for advanced PD-L1-selected NSCLC patients: updated ORR, PFS, OS and exploratory biomarker results from the BIRCH study
Publication History
Publication Date:
23 February 2017 (online)
Background:
Atezolizumab (atezo; MPDL3280A) is a humanized mAb that targets PD-L1, inhibiting interactions with PD-1 and B7.1. BIRCH (NCT02031458) is a single-arm Ph II study of atezo monotherapy in PD-L1-selected pts with advanced NSCLC, across different lines of therapy. Primary analyses (median follow-up of 8.5 mo) demonstrated a meaningful ORR benefit in chemo-naive 1L and 2L+ NSCLC pts. Here updated efficacy and exploratory biomarker data in 1L pts from BIRCH are reported.
Methods:
Eligibility criteria included PD-L1-selected, advanced-stage NSCLC with no active CNS metastases and no prior chemotherapy (1L). PD-L1 was centrally evaluated with the VENTANA SP142 IHC assay. Pts expressing PD-L1 on ≥5% of tumor cells (TC) or tumor-infiltrating immune cells (IC), ie, TC2/3 or IC2/3, were enrolled. Pts received atezo 1200 mg IV q3w until radiographic disease progression or unacceptable toxicity. The primary endpoint was independent review facility-assessed ORR. Key secondary endpoints, including investigator (INV)-assessed ORR, DOR, PFS (RECIST v1.1) and OS, are reported here.
Results:
With a median follow-up of 14.6 mo, INV-assessed ORR was 32% in TC3 or IC3 pts and 24% in TC2/3 or IC2/3 pts. Other clinical benefits, measured by DOR, PFS and OS, were also observed in both PD-L1 groups (Table). No new safety signals were observed. Exploratory biomarker analyses, including efficacy in pts with EGFR or KRAS mutations, will be presented.
TC3 or IC3 n = 65 |
TC2/3 or IC2/3 n = 139 |
|
INV ORRa, n (%), 95% CI |
21 (32%) (21.2, 45.1) |
33 (24%) (16.9, 31.7) |
Median DORa (mo), 95% CI |
13.1 (8.5, NE) |
13.1 (9.9. 17.5) |
Median OS (mo), 95% CI |
NE (12.0, NE) |
20.1 (20.1, NE) |
12-mo OS rate, 95% CI |
61% (48.8, 73.8) |
66% (57.9, 74.5) |
Median PFSa (mo), 95% CI |
7.3 (4.9, 12.0) |
7.3 (5.6, 9.1) |
12-mo PFS rate, 95% CI |
36% (23.8, 48.8) |
32% (24.0, 40.7) |
NE, not estimable. aORR/DOR/PFS assessed by investigator per RECIST v1.1. |
Conclusions:
With longer follow-up, atezo monotherapy continues to demonstrate promising efficacy across a spectrum of endpoints including OS (mOS 20.1 mo in TC2/3 or IC2/3 1L pts). These data support ongoing 1L Ph III trials assessing atezo monotherapy vs. chemotherapy in PD-L1-selected pts.