Science and Research

Five-year survival in patients with extensive-stage small cell lung cancer treated with atezolizumab in the Phase III IMpower133 study and the Phase III IMbrella A extension study

OBJECTIVES: IMbrella A is a Phase III extension study that allowed rollover from Roche/Genentech-sponsored atezolizumab trials, including IMpower133, a Phase I/III trial of first-line atezolizumab or placebo plus carboplatin/etoposide in extensive-stage small cell lung cancer. We report outcomes from an exploratory analysis of IMpower133 with extended time-to-event data for patients who rolled over to IMbrella A. MATERIALS AND METHODS: IMpower133 patients could roll over to IMbrella A to receive atezolizumab 1200 mg intravenously every three weeks if they continued to receive atezolizumab at IMpower133 closure or were in survival follow-up after atezolizumab discontinuation. Overall survival and safety were assessed; only serious adverse events and AEs of special interest were collected in IMbrella A. RESULTS: Eighteen of 26 eligible patients rolled over to IMbrella A. At clinical cutoff (March 16, 2023), median follow-up in the atezolizumab plus carboplatin/etoposide arm (IMpower133 and IMbrella A) was 59.4 months. The three-, four-, and five-year overall survival (95 % CI) estimates were 16 % (11 %-21 %), 13 % (8 %-18 %), and 12 % (7 %-17 %), respectively. In IMbrella A, serious adverse events occurred in three patients (16.7 %), and one adverse event of special interest was reported (grade two hypothyroidism). CONCLUSION: This long-term analysis of patients from IMbrella A previously enrolled in IMpower133 provides the first report of five-year overall survival outcomes in patients with extensive-stage small cell lung cancer treated with first-line cancer immunotherapy and chemotherapy. While limited by small patient numbers and lack of long-term data for the IMpower133 control arm, exploratory overall survival analyses in patients treated with atezolizumab plus carboplatin/etoposide compared favorably with historical data with chemotherapy alone. NCT03148418.

  • Reck, M.
  • Dziadziuszko, R.
  • Sugawara, S.
  • Kao, S.
  • Hochmair, M.
  • Huemer, F.
  • de Castro, G., Jr.
  • Havel, L.
  • Bernabé Caro, R.
  • Losonczy, G.
  • Lee, J. S.
  • Kowalski, D. M.
  • Andric, Z.
  • Califano, R.
  • Veatch, A.
  • Gerstner, G.
  • Batus, M.
  • Morris, S.
  • Kaul, M.
  • Cuchelkar, V.
  • Li, H.
  • Danner, B. J.
  • Nabet, B. Y.
  • Liu, S. V.

Keywords

  • Atezolizumab
  • Carboplatin
  • Clinical Trial
  • Drug Therapy
  • Etoposide
  • Immune Checkpoint Inhibitor
  • Small Cell Lung Carcinoma
  • Survival
Publication details
DOI: 10.1016/j.lungcan.2024.107924
Journal: Lung Cancer
Pages: 107924 
Work Type: Original
Location: ARCN
Disease Area: LC
Partner / Member: Ghd
Access-Number: 39306923

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