Exploratory analysis of IMvigor130 trial finds no OS benefit from atezolizumab in subgroups

Initial response to induction therapy with platinum-based chemotherapy ± atezolizumab in patients with metastatic urothelial cancer (mUC) did not impact overall survival (OS) outcomes in an exploratory analysis of IMvigor130 trial.

Standard-of-care treatment for mUC is platinum-based chemotherapy and, for patients without progression of disease, maintenance checkpoint inhibition is a new therapeutic option [1]. Previously, results from the phase 3 IMvigor130 trial (NCT02807636) showed that the addition of atezolizumab to platinum-based chemotherapy significantly improved progression-free survival but not OS in the intention-to-treat population [2,3]. A post-hoc analysis was conducted of OS by response to the induction therapy. Dr Enrico Grande (MD Anderson Cancer Center, Spain) presented the results [4].

In IMvigor130, 318 patients did not show progression of disease (no progressive disease [PD] subgroup) at or before week 18. They received maintenance treatment with atezolizumab or placebo. Of these patients, 184 did show progression of disease (PD subgroup). In the no PD subgroup, median OS during maintenance was not different in patients treated with atezolizumab/chemotherapy during the induction versus patients treated with placebo/chemotherapy (20.5 vs 19.6 months; HR 0.84). However, in no PD patients with PD-L1 expression (IC2/3), the addition of atezolizumab did improve median OS during maintenance (56.0 vs 21.9 months; HR 0.63).

In the total PD subgroup, the addition of atezolizumab did not improve median post-progression OS (4.3 vs 3.3 months; HR 0.75). However, in cisplatin-treated patients (n=62) atezolizumab did improve median post-progression OS: 6.6 versus 2.5 months (HR 0.56).

Dr Grande concluded that “this exploratory analysis showed that initial responses to induction therapy did not seem to impact OS outcomes.”

1. Powles T, et al. Ann Oncol. 2022;33:244–258.
2. Galsky MD, et al. Lancet Oncol. 2020;395:1547–1557.
3. Galsky MD, et al. ASCO GU 2023, Abstract LBA440.
4. Grande E, et al. Overall survival (OS) by response to first-line (1L) induction treatment with atezolizumab (atezo) + platinum/gemcitabine (plt/gem) vs placebo + plt/gem in patients (pts) with metastatic urothelial carcinoma (mUC): Updated data from the IMvigor130 OS final analysis. Abstract 4503, ASCO Annual Meeting 2023, 2–6 June, Chicago, USA.

 

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Posted on 2 August, 20232 August, 2023