FDA Grants Approval to Frontline Atezolizumab Regimen for NSCLC

Atezolizumab (Tecentriq) has been approved by the FDA for use in combination with bevacizumab (Avastin), carboplatin, and paclitaxel (ABCP) as a first-line treatment for patients with metastatic nonsquamous non-small cell lung cancer (NSCLC). This indication excludes patients withEGFR/ALKaberrations.

The approval was made based on findings from the phase III IMpower150 trial, in which the regimen reduced the risk of death by 22% compared with bevacizumab and chemotherapy (BCP) in patients with advanced wild-type NSCLC.^1,2

Results showed that the median overall survival (OS) with the addition of atezolizumab was 19.2 months (95% CI, 17.0-23.8) compared with 14.7 months (95% CI, 13.3-16.9) in the BCP arm (HR, 0.78; 95% CI, 0.64-0.96;P= .0164). Moreover, the 24-month OS rate with atezolizumab was 43% compared with 34% for BCP. ABCP also improved median progression-free survival (PFS) by 1.5 months compared with BCP (8.3 vs 6.8 months; HR, 0.59; 95% CI, 0.50-0.70;P<.0001).

The trial was designed to exclude data for patients with EGFR/ALK-mutated NSCLC from the co-primary endpoints of OS and PFS. Approximately 13% of the trials participants were&nbsp;EGFR&nbsp;or&nbsp;ALK-positive. Prior to study entry, these patients had received at least 1 prior EGFR TKI.

When patients with EGFR/ALK&nbsp;alterations were included in the intent-to-treat population, the median OS with ABCP jumped to 19.8 months compared with 14.9 months for BCP (HR, 0.76; 95% Cl, 0.63-0.93). Better than expected survival was also seen in patients with liver metastases.

Added efficacy for both groups correlated with the addition of the VEGF inhibitor bevacizumab and atezolizumab. In a separate cohort of the study looking at atezolizumab plus carboplatin and paclitaxel (ACP) there was a less pronounced improvement compared with BCP. In the EGFR/ALK-positive group, the objective response rate (ORR) was 56% with ABCP compared with 40% with ACP and 41% with BCP.

There was a 46% reduction in the risk of death with ABCP compared with BCP for patients with liver metastases (HR, 0.54; 95% CI, 0.33-0.88) and a 46% reduction in the risk of death for patients with EGFR/ALK-mutated NSCLC (HR, 0.54; 95% CI, 0.29-1.03). The risk of death was reduced by 15% (HR, 0.85; 95% CI, 0.53-1.36) and 18% (HR, 0.82; 95% CI, 0.49-1.37) for patients with liver metastases and&nbsp;EGFR/ALK&nbsp;alterations, respectively.

The IMpower150 study enrolled 1202 patients with stage IV non-squamous NSCLC. Patients were randomized evenly to receive ACP (arm A; n = 402), ABCP (arm B; n = 400), or BCP (arm C; n = 400). Approximately 10% of patients were EGFR&nbsp;mutation positive and 2% to 5% of patients had an&nbsp;ALK&nbsp;rearrangement. Liver metastases were present at baseline for 13% of patients.

In the investigational arms, atezolizumab was administered at 1200 mg intravenously every 3 weeks and bevacizumab was given at 15 mg/kg. In each arm, carboplatin and paclitaxel were given on day 1 of each cycle for 4 to 6 cycles. In arm A, maintenance therapy was given with atezolizumab alone and in arm B patients received maintenance therapy with the combination of bevacizumab and atezolizumab. In arm C, maintenance was given with bevacizumab alone.

In the wild-type intent-to-treat population, the 18-month PFS rate was 27% with ABCP and 8% for BCP. The 18-month OS rate was 53% with ABCP compared with 41% for BCP. The ORR with ABCP was 63.5% compared with 48% for BCP, with complete response rates of 3.7% and 1.2%, respectively.

In patients with liver metastases in the wild-type analysis, the median OS with ABCP was 13.2 month compared with 9.1 months with BCP (HR, 0.54). Patients without liver metastases had a median OS of 19.8 versus 16.7 months for ABCP and BCP, respectively (HR, 0.83). The median OS in patients with EGFR/ALK mutations only was not evaluable with ABCP versus 17.5 months for BCP (HR, 0.54).

Favorable efficacy was seen with the ABCP combination compared with BCP across PD-L1 expression levels. In those with PD-L1 high expression (tumor cells [TC] 3 or immune cells [IC] 3; n = 136), the median OS was 25.2 months with ABCP compared with 15.0 months for BCP (HR, 0.70; 95% CI, 0.43-1.13). The ORR in this group was 69% with ABCP compared with 62% with ACP and 49% with BCP. The duration of response with ABCP in this group was 22.1 months compared with 12.2 months with ACP and 7.0 months for BCP.

In the PD-L1—low group (TC1/2 or IC1/2; n = 226), the median OS was 20.3 versus 16.4 months for ABCP and BCP, respectively (HR, 0.80; 95% CI, 0.55-1.15). In the PD-L1&ndash;negative group (TC0/IC0; n = 339), the median OS was 17.1 versus 14.1 months for ABCP and BCP, respectively (HR, 0.82; 95% CI, 0.62-1.08).

Treatment-related grade 3 or 4 adverse event (AEs) occurred in 43% of patients in the ACP group and for 57% and 49% of those in the ABCP and BCP arms, respectively. Serious adverse events occurred in 39%, 44%, and 34% of patients in the ACP, ABCP, and BCP groups. The most common grade 3/4 immune-related AEs were rash (3% with ACP, 2% with ABCP, and 1% with BCP) and hepatitis (3% with ACP, 5% with ABCP, and 1% with BCP).

In September 2018, the FDA extended the review period for the supplemental biologics license application (sBLA) for ABCP for the first-line treatment of patients with metastatic nonsquamous disease. Roche (Genentech), the manufacturer of the PD-L1 inhibitor, previously reported in a press release that the extension would allow sufficient time for the FDA to review additional information it requested for the sBLA.

The FDA noted the recommended dosage for atezolizumab at 1200 mg intravenously (IV) over 60 minutes followed by bevacizumab, paclitaxel, and carboplatin, on day 1 of each 21-day cycle for a maximum of 4 to 6 cycles of chemotherapy. The agency noted that if the first atezolizumab infusion is well tolerated, then all subsequent doses can be given over 30 minutes. Following chemotherapy, atezolizumab should be given at 1200 mg IV followed by bevacizumab on day 1 of each 21-day cycle until disease progression or unacceptable toxicity.

References:

1. Socinski MA, Jotte R, Cappuzzo F, et al. Overall survival (OS) analysis of IMpower150, a randomized Ph 3 study of atezolizumab (atezo) chemotherapy (chemo) &plusmn; bevacizumab (bev) vs chemo + bev in 1L nonsquamous (NSQ) NSCLC. J Clin Oncol. 2018;36 (suppl; abstr 9002).
2. Socinski MA, Jotte R, Cappuzzo F, et al. Atezolizumab for First-Line Treatment of Metastatic Nonsquamous NSCLC. N Engl J Med.Published online June 4, 2018. doi: 10.1056/NEJMoa1716948.