Merck Inc. announced new data from studies evaluating Keytruda.

Presentations demonstrate the company’s scientific expertise and continuing commitment to delivering meaningful advances for patients with melanoma. Key data include exploratory 7-year follow-up from KEYNOTE-006, the pivotal trial that supported the indication for Keytruda in advanced melanoma, and updated findings from the KEYNOTE-716 trial that is evaluating Keytruda as an adjuvant treatment for patients with resected stage IIB or IIC melanoma. These data were both selected for inclusion in plenary sessions at the SMR 2021 Congress.

Data from KEYOTE-587: Exploratory 7-Year Follow-up of KEYNOTE-006 Patients (Plenary Session 11) : KEYNOTE-006 (ClinicalTrials.gov, NCT01866319) was an open-label, randomized Phase III study comparing the efficacy and safety of Keytruda versus ipilimumab in participants with advanced melanoma. After KEYNOTE-006 concluded, participants were eligible to transition to KEYNOTE-587 for extended follow-up. 210 former participants of KEYNOTE-006 (158 patients treated with Keytruda and 52 patients treated with ipilimumab) were assessed for 7-year follow-up. Findings from this long-term follow-up showed that median OS was 32.7 months for Keytruda and 15.9 months for ipilimumab (HR=0.70; [95% CI, 0.58-0.83]). The 7-year OS rates were 37.8% for Keytruda and 25.3% for ipilimumab. Findings from this exploratory analysis showed that Keytruda was associated with improved clinical outcomes regardless of BRAF status, prior BRAFi therapy, and poor prognostic characteristics such as high LDH level, larger tumor size, or presence of brain metastases. These results represent the longest follow-up from a Phase III trial of anti-PD-1/L1 therapy for advanced melanoma available to date. No formal statistical testing was planned.

Data from KEYNOTE-716 (Plenary Session 11): KEYNOTE-716 (ClinicalTrials.gov, NCT03553836) is a multicenter, randomized, double-blind Phase III trial evaluating adjuvant treatment with Keytruda compared to placebo in adult and pediatric (12 years or older) patients with resected stage IIB or IIC melanoma. The trial’s primary endpoint is recurrence-free survival (RFS). At the protocol-specified second interim analysis (IA2), treatment with Keytruda continued to show a clinically meaningful improvement in RFS compared to placebo as adjuvant therapy for these patients, with a reduction in the risk of disease recurrence or death of 39% (HR=0.61 [95% CI, 0.45-0.82]). As previously announced, KEYNOTE-716 met the primary endpoint of RFS at the first interim analysis (HR=0.65 [95% CI, 0.46-0.92]; p=0.00658), and therefore, statistical testing was not performed at IA2. No new safety signals were observed. At IA2, 14.8% (n=72/487) of patients who received Keytruda had recurrence or died compared to 23.5% (n=115/489) of patients on placebo. Median RFS continued to not be reached for either group at the time of this analysis. Twice as many patients on placebo (12.3% [n=60/489]) experienced distant recurrence compared to patients on Keytruda (6.4% [n=31/487]).

The safety profile of Keytruda at IA2 was consistent with previous reports . Treatment-related adverse events (TRAEs) occurred in 82.8% (n=400/483) of patients who received Keytruda versus 63.4% (n=308/486) of patients who received placebo, while Grades 3-4 TRAEs were observed in 17.0% (n=82/483) versus 4.3% (n=21/486) of patients, respectively. Grades 3-4 immune-mediated adverse events and infusion reactions occurred in 10.1% (n=49/483) of patients and 1.2% (n=6/486) of patients in the Keytruda and placebo arms, respectively.