Merck & Co. announced that the FDA broadened the cervical cancer label for its PD-1-targeting immunotherapy Keytruda (pembrolizumab), but stopped short of including the overall population represented in a pivotal Phase III study. This new indication – the third for Keytruda in cervical cancer – is for use in combination with chemoradiotherapy (CRT) as treatment for newly-diagnosed patients with FIGO 2014 Stage III-IVA disease.
The decision was based on results from the KEYNOTE-A18 trial, which enrolled 1060 patients with high-risk, locally advanced cervical cancer who had not previously received any definitive surgery, radiation or systemic therapy for their disease. Subjects were roughly split between those with FIGO 2014 Stage III-IVA cervical cancer with either node-positive or node-negative disease, and those with FIGO 2014 Stage IB2-IIB cervical cancer with node-positive disease.
PFS benefit driven by later-stage cohort
Results demonstrated a significant improvement in progression-free survival (PFS) in the overall study population, although an exploratory analysis among the earlier-stage cohort suggested most of that benefit was derived from the 56% of trial participants who had Stage III-IVA disease. In this later-stage cohort, there was a PFS benefit of 41% with Keytruda versus placebo plus CRT, whereas the benefit was only 9% for the earlier-stage group. Merck noted that overall survival data were not mature at the time of the PFS analysis.