How do you treat metastatic small cell carcinoma of the bladder cancer refractory to first line cisplatin based therapy?

Clinical trial is ideal; if no trial is available, consider taxane single-agent vs anti-PD(L)1 single-agent, send NGS testing to look for targets. No high-level evidence exists to help select 2L therapy but reasonable to assess TMB and favor pembrolizumab if high TMB as per recent FDA approval. Ther...