In patients with resected high-risk stage 3 cutaneous melanoma, distant metastasis-free survival at 3.5 years was 65.3% in patients treated with Keytruda compared with 49.4% in those treated with placebo, which was also consistent in patients with PD-L1-positive tumors.
Over a median 3.5 years of follow-up, adjuvant therapy with Keytruda (pembrolizumab) significantly improved distant metastasis-free survival in patients with resected high-risk stage 3 cutaneous melanoma compared with placebo, according to data published in Lancet Oncology.
“The treatment differences in distant metastasis-free survival rates over time were consistent with the ones in recurrence-free survival rates, confirming the sustainability of the treatment effect,” the study authors wrote.
In this phase 3 trial, researchers analyzed data from 1,019 patients with complete resection of cutaneous melanoma metastatic to the lymph node. Patients were assigned 200 milligrams of Keytruda intravenously (514 patients) or placebo (505 patients) every three weeks for up to 18 doses, or until unacceptable toxicity or disease recurrence.
Researchers assessed recurrence-free survival (time from treatment assignment to first recurrence or all-cause death), distant metastasis-free survival (time from treatment assignment to first distant metastasis or all-cause death), both of which were analyzed in all patients and in those with PD-L1-positive tumors (853 patients). Overall follow-up was conducted for a median of 42.3 months.
In the overall patient population, distant metastasis-free survival at 3.5 years was higher in patients treated with Keytruda compared with those treated with placebo (65.3% versus 49.4%). For patients with PD-L1-positive tumors, distant metastasis-free survival was 66.7% in the Keytruda group and 51.6% in the placebo group.
Patients in the overall population treated with Keytruda also had longer recurrence-free survival compared with those who received placebo (59.8% versus 41.4%). This was also observed in patients with PD-L1-positive tumors (61.4% versus 44.1%).
Researchers noted that a potential limitation of the study was that not all patients could be assessed for distant metastasis-free survival after they were no longer taking their assigned treatment because of instances such as withdrawn consent or a side effect.
“The number of patients without a recent disease assessment were small and well balanced between the two treatment groups and, therefore, this problem is expected to have little effect on the distant metastasis-free survival comparison.”
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