Top Line: What is the pathologic complete response rate with radioimmunotherapy for muscle invasive bladder cancer?
The Study: The standard treatment for MIBC in patients who are not candidates for or who refuse radical cystectomy is TURBT followed by chemoradiation. Immunotherapy plays an important role in the treatment of advanced and metastatic bladder cancer, and ongoing trials are investigating the role of ICI with radiation and chemoradiation. BPT-ART is a phase 2 trial investigating the efficacy of radiation and immunotherapy alone for MIBC. It enrolled 45 patients with high risk T1 (15.6%) or T2-3N0 MIBC measuring <5cm (57.8% were < 3cm). Of note, two-thirds had complete resection by TURBT prior to enrollment. Patients were treated with 41.4 Gy in 23 fractions to the whole pelvis with a cone-down boost to a total of 57.6 Gy to the whole bladder. Atezolizumab was started along with radiation and given every 3 weeks for a total of 8 cycles. Here we have initial report of the secondary outcome of pathologic complete response. At 24 weeks after radiation, repeat TURBT showed a pCR rate of 84.4%. For comparison, the pCR rate for neoadjuvant immunotherapy is in the 30-50% range. This trial was small, and it’s hard to compare subsets, but those with PD-L1 expression had a higher pCR rate (95.8% v 71.4%). The rate of grade 3 toxicity was 13.3%. PFS outcomes from BPT-ART are still maturing.
TBL:: In this small trial, the combination of radiation and atezolizumab alone resulted in a favorable pCR rate of 84.4% for patients with MIBC who were not cystectomy candidates. | Kimura, Int J Radiat Oncol Biol Phys 2023
The Study: The standard treatment for MIBC in patients who are not candidates for or who refuse radical cystectomy is TURBT followed by chemoradiation. Immunotherapy plays an important role in the treatment of advanced and metastatic bladder cancer, and ongoing trials are investigating the role of ICI with radiation and chemoradiation. BPT-ART is a phase 2 trial investigating the efficacy of radiation and immunotherapy alone for MIBC. It enrolled 45 patients with high risk T1 (15.6%) or T2-3N0 MIBC measuring <5cm (57.8% were < 3cm). Of note, two-thirds had complete resection by TURBT prior to enrollment. Patients were treated with 41.4 Gy in 23 fractions to the whole pelvis with a cone-down boost to a total of 57.6 Gy to the whole bladder. Atezolizumab was started along with radiation and given every 3 weeks for a total of 8 cycles. Here we have initial report of the secondary outcome of pathologic complete response. At 24 weeks after radiation, repeat TURBT showed a pCR rate of 84.4%. For comparison, the pCR rate for neoadjuvant immunotherapy is in the 30-50% range. This trial was small, and it’s hard to compare subsets, but those with PD-L1 expression had a higher pCR rate (95.8% v 71.4%). The rate of grade 3 toxicity was 13.3%. PFS outcomes from BPT-ART are still maturing.
TBL:: In this small trial, the combination of radiation and atezolizumab alone resulted in a favorable pCR rate of 84.4% for patients with MIBC who were not cystectomy candidates. | Kimura, Int J Radiat Oncol Biol Phys 2023