Efficacy and safety of atezolizumab concurrent with radiotherapy in patients with muscle-invasive bladder cancer: An interim analysis of the atezobladderpreserve phase II trial (SOGUG-2017-A-IEC(VEJ)-4).

• DOI: 10.1200/jco.2024.42.16_suppl.4592
• Publication Date: 2024-10-04T15:42:58Z
• Authors: Ovidio Fernandez ...; Teresa Bonfill; Francisca Martine...; Nuria Romero-Laorden; Silvia Sequero-Lopez; Montserrat Domene...; Elena Sevillano; José García Sánchez; Pilar Canoa Román; Carlos Álvarez-Fe...; Sergio Vazquez-Es...
• Keywords: Atezolizumab; Interim analysis; Interim

4592 Background: Combined-modality treatments (CMTs) are bladder-preserving alternatives for patients (pts) ineligible radical cystectomy. CMTs combine maximal transurethral resection (TUR) of bladder tumor, radiotherapy (RT), and chemotherapy. Emerging immune therapies seem to enhance RT-induced tumor-specific response. RT combined with anti-PD-1/PD-L1 therapy shows promising efficacy acceptable toxicity. This ongoing study evaluates the safety atezolizumab (ATZ) concurrent external beam (EBRT) muscle-invasive cancer (MIBC) treatment as preservation therapy. Here, we present an interim analysis. Methods: Open, multicenter, phase II trial in adults MIBC clinical stages cT2-T4a N0 M0 not candidates Treatment involves 6 doses ATZ (1200 mg IV/3 weeks) from day 1 EBRT 60 Gy 30 fractions over weeks at 2 Gy/day. The primary endpoint is pathological complete response (pCR), a grade 5 per Miller Payne criteria, 1-2 months after last dose. An analysis (data cut-off: Oct. 2023) encompassing data screening visits has been conducted. Adverse events (AE) serious AE (SAE) incidence secondarily assessed. Results: From Sep. 2019 2023, 59 pts were screened; 20 excluded non-compliance eligibility criteria (15 pts), consent withdrawal (6 (1 pt). Evaluable population consisted 39 pts. Median age was 79.7 years. Most had T2a (61.5%) T2b (25.6%). 37 (94.9%) least one previous clinically significant condition, 24 prior surgery, (100%) receiving concomitant medication. TUR performed 23 (71.9%) All 26 assessment visit achieved pCR; none underwent experienced AEs (23 [59.0%] AE, 13 [33.3%] 3, [2.6%] pt 3), asthenia (21 pts) diarrhea (17 being most common. related occurred pts; those 21 (53.8%). (33.3%) SAE (including renal failure 3 hepatotoxicity one). One (2.6%) (7.7%) SAEs ATZ. leading discontinuation death (5.1%), them treatment. Conclusions: Interim results suggest that seems be effective achieving pCR vulnerable elderly multiple comorbidities. profile appears manageable. final this will provide valuable insights into effect on outcomes, such survival, addition updated data. Clinical information: NCT04186013 .