“However, in a prespecified subgroup analysis, pemetrexed-cisplatin showed OS and PFS (progression-free survival) advantage for patients with performance status 0 or 1 or oropharyngeal cancers,” the authors report.
Dr. Susan Urba, at the University of Michigan Comprehensive Cancer Center in Ann Arbor, and colleagues point out that survival is poor in recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). While cisplatin is considered standard treatment, pilot studies have indicated that pemetrexed has activity in this setting.
The current randomized, double-blind trial examined outcomes in 398 patients with inoperable recurrent or metastatic SCCHN treated with pemetrexed and cisplatin therapy compared with 397 patients given placebo plus cisplatin.
Median overall survival was 7.3 months in the pemetrexed-cisplatin arm compared with 6.3 months in the placebo-cisplatin arm, a nonsignificant difference (p=0.082), the researchers report. Corresponding progression-free survival times were 3.6 months versus 2.8 months (p=0.166).
However, among patients with good performance status (ie, 0 or 1), overall survival in the two arms was 8.4 vs 6.7 months, respectively, (p=0.026) and progression-free survival times were 4.0 vs 3.0 months (p=0.044), according to the report.
Similarly, pemetrexed made a significant difference in patients with oropharyngeal cancers, with overall survival of 9.9 months in the group given pemetrexed-cisplatin compared with 6.1 months in the placebo-cisplatin group (p=0.002). Corresponding progression-free survival times were 4.0 vs 3.4 months (p=0.047), Dr. Urba and colleagues report.
Given the improvement in these subgroups of patients “and the known mild safety profile of pemetrexed monotherapy,” they note, “a phase 2 study is investigating the benefits of pemetrexed for treating higher-risk patients who are less likely to tolerate triplet therapy.”