...- In mRCC with MSI-H, the patient must have received immunotherapy....

Tumors with high microsatellite instability (MSI-H) had a significantly lower odds of progression of disease (POD) as best objective response (p = 0.01) and a significantly longer median PFS (p = 0.022) compared with tumors with microsatellite stability (MSS) in multivariable models (Table)...Our study showed that MSI-H mCRC was associated with significantly better response to rego and PFS, even in the absence of prior IO.

For 3L and later, combination therapy was preferred over monotherapy but decreased in usage (75% for 3L vs. 57% for 4L). Fluoropyrimidine + irinotecan with or without an EGFR/VEGF inhibitor was the most common combination regimen (N¼12) and 5 patients received regorafenib in 3L. The median OS for dMMR/MSI-H mCRC patients receiving 3L therapy was 9.0 months (95% Confidence Interval (CI): 4.0-14.1). Median OS decreased to 4.1 months (95% CI: 4.0-9.0) when survival data of patients receiving ICIs at 4th or later lines were censored at progression date of prior treatment line. BORR was 5.7% (2 patients with PRs), and 31.4% (11 patients) showed stable disease (SD) for 3L treatment.