Chemotherapy Re-challenge in Metastatic Colorectal Cancer
Posted: Tuesday, October 9, 2018
According to a study published in the Journal of Gastrointestinal Oncology, reinitiation of oxaliplatin- or irinotecan-based regimens may prove to be a useful option in the third- or fourth-line setting for select patients with metastatic colorectal cancer. Clinical benefit rates and time to disease progression appear to be comparable to those of other approved third-line therapies, such as regorafenib or trifluridine-tipiracil.
The retrospective, cohort study, led by Alexandra E. Chambers, PharmD, BCOP, of Banner MD Anderson Cancer Center, Gilbert, Arizona, and colleagues, enrolled 51 patients with metastatic colorectal cancer. Overall, 67 chemotherapy re-challenges were administered. All patients received at least 1 chemotherapy re-initiation, and 14 patients underwent a second re-challenge.
The overall clinical benefit rate among all patients was 70.7%. Of these patients, 50.7% achieved a partial response. Among patients in the first re-challenge group, the clinical benefit rate was 75.5%, compared with 61.5% among those receiving a second re-challenge. The time to disease progression was 6.6 months after initiation of the first re-challenge, and it decreased to 4.1 months after the second.
Despite a higher clinical benefit rate and longer time to disease progression with irinotecan versus oxaliplatin (88.2% vs. 70.5%; 240.00 days vs. 171.50 days, respectively), the differences were not statistically significant. The time to disease progression was significantly longer among partial responders than in those with stable disease (279.11 days vs. 157.91 days; P = .003), which, the authors noted, may be a helpful factor to identify patients who may benefit most from chemotherapy re-challenge.
“Up to 70% of patients may experience clinical benefit from chemotherapy re-challenge as a third or fourth line option for [metastatic colorectal cancer] despite prior exposure to irinotecan or oxaliplatin,” the authors concluded.