Sasanlimab as bladder-sparing maintenance treatment after neoadjuvant chemotherapy in patients with muscle invasive bladder cancer (MIBC): The phase 2, SASAN-SPARING trial.

• DOI: 10.1200/jco.2025.43.16_suppl.tps4626
• Publication Date: 2025-05-28T14:20:16Z
• Authors: Elena Sevillano; Julia Martinez Perez; Nuria Lainez Milagro; Pablo Gajate Borau; Xavier Garcia del...; Javier Puente; Miguel Angel Climent; Alfonso Gomez de ...; Oscar Reig Torras; Guillermo de Velasco
• Keywords: Urothelial cancer

TPS4626 Background: Radical cystectomy (RC), traditionally considered the gold standard for MIBC, carries significant morbidity, negatively impacting patients' quality of life. Recent studies have demonstrated that neoadjuvant cisplatin-based chemotherapy combined with immunotherapy can induce a complete or major pathological response in subset patients, allowing consideration less invasive therapeutic alternatives. High comorbidity rates MIBC often preclude radical cystectomy. Sasanlimab, PD-1 inhibitor, may enhance efficacy chemotherapy, potentially enabling bladder preservation responding patients and improving outcomes. Methods: The SASAN-SPARING trial is single-arm, non-randomized, non-blinded, phase 2 evaluates safety sasanlimab as maintenance treatment localized undergo sparing strategy chemotherapy. A total 70 will be accrued 10 hospitals Spain. Patients are ≥ 18 years, ECOG 0-1 treatment-naïve candidates to receive cisplatin/gemcitabine followed by RC. All 4 cycles cisplatin (70 mg/m2) on day 1 every 3 weeks gemcitabine (1000 days 8 3-week cycle. After restaged those achieving clinical (absence disease cytology, imaging, cT0/Ta/T1/Tis) allowed proceed without RC 300 mg subcutaneous up 12 cycles. Tumor assessments including MRI, cystoscopy cytology scheduled weeks. primary endpoint bladder-intact overall survival (biOS) rate at months after first dose sasanlimab. Assuming 12-month biOS 81% (H0) an increase 93% (H1), study requires included which 47 treated (one arm test; α = 0.05 β= 0.8). includes ambitious biomarker substudy evaluate use ctDNA blood urine samples tumor assessment molecular dynamics under pressure. In addition, gut microbiome used this end. Study biomarkers provide useful tool corroborate achievement response, contributing personalized treatments. approved started recruitment December 2024. Clinical information: NCT06623162 .