The U.S. Food and Drug Administration (FDA) approved atezolizumab in combination with carboplatin and etoposide for firstline treatment of adults with extensive-stage small cell lung cancer.
The decision was based on results from the multicenter, double-blinded, randomized, placebo-controlled, phase III IMpower133 study, which enrolled 403 patients who were randomized 1:1 to receive atezolizumab in combination with carboplatin and etoposide (n=201) or placebo in combination with carboplatin and etoposide (control arm; n=202).
Improved Survival With Atezolizumab
The findings demonstrated that atezolizumab plus chemotherapy improved median overall survival (OS) compared with chemotherapy alone (12.3 vs. 10.3 months; hazard ratio [HR] = 0.70, 95% CI, 0.54-0.91; P=0.0069). Atezolizumab plus chemotherapy also significantly increased progression-free survival (5.2 vs. 4.3 months; HR=0.77; 95% CI, 0.62-0.96; P=0.017).
The one-year OS rate was 51.7% in the atezolizumab group and 38.2% in the placebo group, while the objective response rate was 60% and 64%, respectively. The median duration of response was longer in the atezolizumab group (4.2 months vs. 3.9 months).
Puzzling for @US_FDA to approve nivo now for SCLC based on such not very timely & relatively modest data (both in terms of N & results) when phase III IMpower133 trial is being presented at WCLC in 1 mo & will show OS benefit w/1st line carbo/drop/atezolizumab. #LCSM https://t.co/Gxpu8cZoqj
— H. Jack West, MD (@JackWestMD) August 17, 2018
Safety Profile of Atezolizumab
Adverse events (AEs) associated with the atezolizumab cohort were consistent with the known safety profile of the drug. Grade 3/4 AEs were reported in 56.6% of the atezolizumab group and 56.1% of the control group. Serious AEs occurred in 37% of patients in the atezolizumab cohort compared with 35% of the chemotherapy alone group. The most common AEs in the atezolizumab group were fatigue/asthenia (39%), nausea (38%), alopecia (37%), decreased appetite (27%), constipation (26%), and vomiting (20%).
Atezolizumab is also FDA-approved in combination with bevacizumab, paclitaxel, and carboplatin for the firstline treatment of adults with metastatic non-squamous non-small cell lung cancer (NSCLC) with no EGFR or ALK genomic tumor aberrations. It is also FDA-approved to treat adults with metastatic NSCLC who experience disease progression during or following platinum-containing chemotherapy.
…and another one! FDA approves IMpower133: Etoposide, carboplatin and atezolizumab in extensive stage small cell lung cancer.
— Tom Newsom-Davis (@tnewsomdavis) March 19, 2019