A Phase II Trial of Transurethral Surgery Followed by a Combination of Atezolizumab (Tecentriq™) an Anti-PDL-1 (MPDL3280A) With Trimodal Therapy in Patients With Muscle-Invasive Bladder Cancer

This will be a Phase II trial (stage 1 and 2). This study will initially accrue 3 evaluable patients to assess the dose limiting toxicity (DLT) of combination of Gemcitabine (4 weeks at 100 mg/m2, given intravenously once weekly, 2-4 hours before radiation therapy) plus IMRT (50 Gy/20 fractions. 2.5 Gy per fraction - 5 times per week for 4 weeks) and Atezolizumab (1200 mg intravenous on day 1 of 3 week cycle. Once the first 3 patients are accrued, the trial will be placed on hold for 3 months until acute toxicity has been assessed and the combination is felt to be safe according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE,v. 4.03). DLT will be defined as: (1) Grade 3 or higher immune related Adverse Events (irAEs), (e.g. inflammatory ocular toxicities, pneumonitis, hepatitis, colitis), (2) Grade 3 or higher treatment-related AEs (TRAE) that delay EBRT by > 21 days. For the safety run-in component of the study, 3 patients will receive Atezolizumab at a dose of 1200 mg every 3 weeks, as described above. After the third patient has been accrued, the trial will be placed on hold for 3 months for an assessment of acute toxicity. Acute toxicity is defined as any toxicity occurring within 90 days from the end of the combined treatment of IMRT and gemcitabine. If no grade 3 or higher acute toxicity is detected, Atezolizumab 1200 mg will be chosen for the rest of the trial. If one patient develops grade 3 toxicity, 3 further patients will be entered at 1200 mg. . If no further grade 3 toxicity is observed, this dose level will be considered safe. In case that one additional patient develop a grade 3 toxicity, then 3 patients will be enrolled at the reduced dose of 840mg. If no grade 3 or higher acute toxicity is detected, Atezolizumab 840mg will be chosen for the rest of the trial. If one patient develops grade 3 toxicity at the reduced dose, then 3 further patients will be entered at 840 mg. If no further grade 3 toxicity is observed, this reduced dose level will be considered safe. In case that one additional patient develop a grade 3 toxicity at the reduced dose level, it will be considered too toxic and the combination will be judged too toxic for the population and regimen, and the study will be terminated.

If treatment is well tolerated, this will be considered the final dose for the study. No further de-escalation beyond this level will be considered. For the Stage 2 of this study,, up to 22 other patients will be accrued (total of 25 evaluable patients). Atezolizumab will be given during combination treatment, and every 3 weeks for 16 cycles or until disease progression or unacceptable toxicity.