A prospective observational study of treatment sequencing with regorafenib and FTD/TPI in metastatic colorectal cancer: The OSERO study.

BACKGROUND

Regorafenib (REG) monotherapy and trifluridine/tipiracil (FTD/TPI), with or without bevacizumab (BEV), are standard later-line treatments for metastatic colorectal cancer (mCRC). However, the optimal treatment sequence remains uncertain.

METHODS

The OSERO study was a prospective observational study in patients with mCRC scheduled for later-line treatment with REG or FTD/TPI, with or without BEV (UMIN000040586). Patients were categorized into REG (A), FTD/TPI (B), and FTD/TPI plus BEV (C). The primary endpoint was overall survival (OS). To adjust for imbalances in baseline characteristics, stabilized inverse probability of treatment weights (IPTWs) derived from a propensity score model were applied.

RESULTS

Among 468 patients, (A, n = 154; B, n = 82; C, n = 232), scheduled second-line treatment rates were 65.6%, 37.8%, and 62.9%. Median overall survival (mOS) was 12.2, 7.5, and 10.6 months, respectively. After IPTW adjustment, mOS was 12.2 (A) and 10.6 months (C) (hazard ratio, 1.03; 95% confidence interval, 0.81-1.30; P = 0.837). Grade ≥ 3 adverse events ( > 10%) included hand-foot syndrome, proteinuria, and hypertension in (A), and neutropenia and anemia (B, C).

CONCLUSION

Sequential treatment with REGO and FTD/TPI plus BEV therapy yielded comparable survival, suggesting that treatment selection may depend on safety profiles of each drug.