IMpower210: A phase III study of second-line atezolizumab vs. docetaxel in East Asian patients with non-small cell lung cancer.

Objective: IMpower210 (NCT02813785) explored the efficacy and safety of single-agent atezolizumab vs. docetaxel as second-line treatment for advanced non-small cell lung cancer (NSCLC) in East Asian patients. Methods: Key eligibility criteria for this phase III, open-label, randomized study included age ≥18 years; histologically documented advanced NSCLC per the Union for International Cancer Control/American Joint Committee on Cancer staging system (7th edition); Eastern Cooperative Oncology Group performance status of 0 or 1; and disease progression following platinum-based chemotherapy for advanced or metastatic NSCLC. Patients were randomized 2:1 to receive either atezolizumab (1,200 mg) or docetaxel (75 mg/m2). The primary study endpoint was overall survival (OS) in the intention-to-treat (ITT) population with wild-type epidermal growth factor receptor expression (ITT EGFR-WT) and in the overall ITT population. Results: Median OS in the ITT EGFR-WT population (n=467) was 12.3 [95% confidence interval (95% CI), 10.3-13.8] months in the atezolizumab arm (n=312) and 9.9 (95% CI, 7.8-13.9) months in the docetaxel arm [n=155; stratified hazard ratio (HR), 0.82; 95% CI, 0.66-1.03]. Median OS in the overall ITT population was 12.5 (95% CI, 10.8-13.8) months with atezolizumab treatment and 11.1 (95% CI, 8.4-14.2) months (n=377) with docetaxel treatment (n=188; stratified HR, 0.87; 95% CI, 0.71-1.08). Grade 3/4 treatment-related adverse events (TRAEs) occurred in 18.4% of patients in the atezolizumab arm and 50.0% of patients in the docetaxel arm. Conclusions: IMpower210 did not meet its primary efficacy endpoint of OS in the ITT EGFR-WT or overall ITT populations. Atezolizumab was comparatively more tolerable than docetaxel, with a lower incidence of grade 3/4 TRAEs.

Results from the IMpower132 China cohort: Atezolizumab plus platinum-based chemotherapy in advanced non-small cell lung cancer.

BACKGROUND: The global Phase III IMpower132 study evaluating atezolizumab plus pemetrexed and carboplatin or cisplatin (APP) versus pemetrexed plus carboplatin or cisplatin (PP) for first-line treatment of non-squamous advanced non-small cell lung cancer (NSCLC) met its co-primary progression-free survival (PFS) endpoint at the primary analysis in the intention-to-treat (ITT) population. Although the co-primary overall survival (OS) endpoint was not met, numerical OS improvement favoring APP over PP was observed at the final analysis. We report primary results for Chinese patients in IMpower132. METHODS: Treatment-naive Chinese patients with non-squamous stage IV EGFR/ALK mutation-negative NSCLC were randomized 1:1 to receive 4 or 6 cycles of APP or PP, followed by maintenance atezolizumab plus pemetrexed or pemetrexed. Co-primary endpoints were investigator-assessed PFS and OS. RESULTS: The ITT population included 163 Chinese patients (82 in the APP arm and 81 in the PP arm). At data cutoff (median follow-up, 11.7 months), the median PFS in the APP and PP arms was 8.3 and 5.8 months, respectively; the unstratified hazard ratio (HR) was 0.73 (95% CI: 0.50, 1.08). At the interim OS analysis, median OS was not estimable in either arm; the unstratified HR was 0.70 (95% CI: 0.40, 1.24). No new safety signals were observed. CONCLUSION: Among Chinese patients in IMpower132, PFS benefit was seen with APP versus PP. Though interim OS data were immature, there was a trend toward OS benefit favoring APP versus PP. The safety profile of the APP was consistent with the known risks of the individual treatment components. CLINICALTRIALS: gov: NCT02657434.

Pan-cancer population pharmacokinetics and exposure-safety and -efficacy analyses of atezolizumab in patients with high tumor mutational burden.

We retrospectively investigated the pharmacokinetics and exposure-efficacy/safety relationships of single-agent atezolizumab based on tissue tumor mutational burden (tTMB) status (high vs low [≥16 vs <16 mutations/megabase]) in a pan-tumor population from seven clinical trials. Data sources included the OAK, POPLAR, BIRCH, FIR, IMvigor210, IMvigor211, and PCD4989g studies; 986 of 2894 treated patients (34%) had TMB data. Exposure metrics were obtained using a prior two-compartment intravenous-infusion population-pharmacokinetics model, merged with prognostic, biomarker, efficacy, and safety variables. Baseline demographic/clinical characteristics and prognostic factors were well balanced between patients with high (n = 175) and low (n = 811) tTMB. Exposure was similar in the high- and low-tTMB subgroups, with no difference seen in the evaluable vs total treated populations. The objective response rate (ORR) was 29.7% vs 13.4%, complete response rate was 6.9% vs 3.2%, and median duration of response (95% CI) was 29.0 (18.6-NE) months vs 15.9 (12.5-20.5) months for patients with high-tTMB vs low-tTMB tumors, respectively. A flat exposure-efficacy relationship was seen for ORR in patients with high-tTMB based on the cycle 1 minimum atezolizumab concentration and area under the serum concentration time curve (AUC). A nonsignificant exposure-safety profile was seen for grade 3/4 adverse events and adverse events of special interest based on the AUC of atezolizumab in the high-tTMB population. tTMB is an additional predictive biological factor affecting response to atezolizumab, and quantitative investigations of atezolizumab exposure and relationships of exposure with safety and efficacy support the use of a 1200-mg, every 3-week regimen in a tumor-agnostic high-tTMB population.