KEY TAKEAWAYS
- The IMpassion030 phase III trial aimed to compare OS and safety in TNBC patients receiving standard chemo with or without added atezolizumab.
- The primary endpoint was iDFS. Secondary endpoints were iDFS, OS, safety, patient functioning, and HRQoL.
- The result showed that adding atezolizumab to TNBC, chemo likely won’t improve survival but increases side effects.
While early detection is crucial for all breast cancers(BC), triple-negative breast cancer(TNBC) poses a unique challenge due to its increased risk of recurrence in distant sites, even after initial treatment. The study compared overall survival(OS) and safety in TNBC patients receiving standard chemotherapy(chemo) with or without added atezolizumab.
About 2300 operable stage II-III TNBC patients were randomized in a 1:1 ratio, confirmed by central pathology review. Stratification factors included surgery type, nodal status status (0 versus 1-3 versus >=4 nodes), and centrally assessed PD-L1 status(IC 0 vs >=1% ). Adjuvant chemo consisted of paclitaxel followed by dose-dense anthracycline(epirubicin 90 mg/m2 or doxorubicin 60 mg/m2) and cyclophosphamide with or without atezolizumab.
The primary endpoint was invasive disease-free survival (iDFS), with secondary endpoints including iDFS in PD-L1 positive and lymph node-positive subpopulations, OS, safety, and patient functioning/health-related quality of life(HRQoL). Accrual was temporarily halted on November 14, 2022, and the protocol was amended in February 2023 for an early interim analysis based on an IDMC recommendation at approximately 62% of planned iDFS events(390), with a futility boundary set at an HR > 1.
The IDMC recommendations reported that the primary endpoint crossed the futility boundary, accrual to the study was permanently stopped, and the experimental treatment was discontinued. Between August 2018 and November 2022, the study enrolled 2199 patients, with 1,101 randomized to the atezolizumab arm (A) and 1,098 to the control arm (B).
At a median follow-up of 25.3 months, 239 (10.9%) iDFS events were observed in the 2,199 enrolled patients; 127 versus 112 iDFS events were observed (61.3% of 390) in the A versus B arms respectively, (HR 1.12, 95% CI, 0.87, 1.45). In the PD-L1 positive subgroup, 1567/2199 patients (71.3% of patients), 77 versus 73 iDFS events were observed in the A versus B arms, respectively (HR 1.03, 95% CI 0.75, 1.42).
Among patients with lymph node-positive tumors (1066/2199 patients, 48.5%), 86 versus 66 iDFS events were observed in the A versus B arm, respectively (HR 1.41, 95% CI 1.02, 1.96). Incidence of adverse events grade >=3 was 58.01% versus 48.15% in the A versus B arms, including death in 1.01% (11) and 0.55% (6) of patients, respectively.
The result showed that adding atezolizumab to TNBC, chemo likely won’t improve survival but increases side effects.
Source: https://atgproductions.net/atgclients/sabcs/2023_SABCS_Abstract_Report-12-1-23_Compressed.pdf
Clinical Trial: https://clinicaltrials.gov/study/NCT03498716
Ignatiadis, M., Bailey, A., McArthur, H., et al. (2023). “Adding atezolizumab to adjuvant chemotherapy for stage II and III triple-negative breast cancer is unlikely to improve efficacy: interim analysis of the ALEXANDRA/IMpassion030 phase 3 trial.” Presented at the SABCS 2023 – 46th Annual San Antonio Breast Cancer Symposium, December 05 – December 09, 2023, San Antonio, TX, US (Abstract GS01-03).
