The FDA approved pembrolizumab in combination with chemoradiotherapy for the treatment of certain women with stage III to stage IVA cervical cancer.

This is the third approved cervical cancer indication for pembrolizumab (Keytruda, Merck), an anti-PD-1 therapy. The FDA previously approved the agent in combination with chemotherapy, with or without bevacizumab, for the treatment of women with PD-L1-expressing persistent, recurrent, or metastatic cervical cancer and as monotherapy for women with recurrent or metastatic cervical cancer who experienced disease progression while receiving or after chemotherapy.

The agency based the new indication on data from the double-blind phase 3 KEYNOTE-A18 trial, which assessed pembrolizumab plus chemoradiotherapy compared with placebo in patients with International Federation of Gynecology and Obstetrics (FIGO) 2014 stage III to stage IVA disease.

The study enrolled 1,060 women with cervical cancer who had not previously received any definitive surgery, radiation or systemic therapy.

Researchers randomly assigned patients in a 1:1 ratio to receive 200 mg IV pembrolizumab every 3 weeks for five cycles concurrent with 40 mg/m² IV cisplatin for five cycles with radiotherapy, followed by 400 mg IV pembrolizumab every 6 weeks for 15 cycles, or the same regimen with placebo instead of pembrolizumab.

PFS and OS served as the study’s major efficacy outcomes measurements.

Researchers observed a statistically significant improvement in PFS in the overall population; patients in the investigative cohort had a 41% reduction in risk for disease progression or death (HR = 0.59; 95% CI, 0.43-0.82) compared with those in the placebo group.

Researchers noted that the study did not reach a median PFS in either group and determined OS data to be not mature at time of PFS analysis.

“Today’s approval of Keytruda plus chemoradiotherapy is welcome news and gives patients with newly diagnosed FIGO 2014 stage III-IVA cervical cancer, for the first time ever, the option of an anti-PD-1–based regimen to treat their cancer,” Bradley Monk, MD, oncologist and professor of obstetrics and gynecology at University of Arizona’s College of Medicine and Creighton University School of Medicine, said in a Merck press release. “This Keytruda-based regimen offers a new treatment option for these patients, so today’s approval has important implications for the way we treat them moving forward.”

Researchers observed serious adverse reactions in 30% of patients who received pembrolizumab plus chemoradiotherapy; serious adverse reactions included urinary tract infections (2.7%), urosepsis (1.4%) and sepsis (1%).

Researchers discontinued pembrolizumab for adverse reactions in 7% of patients during the study.