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FDA Expands Pembrolizumab Approval in Cervical Cancer

— PD-1 inhibitor approved in combination with CRT for locally advanced disease

Ƶ MedicalToday
FDA APPROVED Pembrolizumab (Keytruda) with chemoradiotherapy (CRT) over a computer rendering of cervical cancer cells.

The FDA approved (CRT) for patients with stage III-IVA cervical cancer based on International Federation of Gynecology and Obstetrics (FIGO) 2014 criteria.

Pembrolizumab is the first anti-PD-1 therapy approved in combination with CRT for these patients, .

Approval was based on data from the phase III KEYNOTE-A18 trial, which showed that the pembrolizumab-based regimen reduced the risk of disease progression or death by 41% (HR 0.59, 95% CI 0.43-0.82) compared with placebo plus CRT among patients with advanced disease.

"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," said Bradley Monk, MD, of the University of Arizona College of Medicine in Phoenix, in Merck's 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."

KEYNOTE-A18 was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled 1,060 patients with cervical cancer who had not previously received definitive surgery, radiation, or systemic therapy. The trial included 596 patients with FIGO 2014 stage III to IVA cervical cancer and 462 patients with FIGO 2014 stage IB2 to IIB, node-positive disease who were randomized to receive pembrolizumab 200 mg or placebo every 3 weeks for five cycles plus CRT, followed by pembrolizumab 400 mg or placebo every 6 weeks for 15 cycles.

The CRT regimen included cisplatin 40 mg/m2 IV weekly for five cycles (with an optional sixth cycle) and external beam radiation therapy followed by brachytherapy.

The pembrolizumab-based regimen demonstrated a statistically significant improvement in progression-free survival (PFS) in the overall population. However, exploratory subgroup analyses showed that for patients with stage IB2 to IIB disease, the PFS hazard ratio estimate was 0.91 (95% CI 0.63-1.31), indicating that the PFS improvement in the overall population was driven by results observed in patients with stage III to IVA disease.

The 12-month PFS rate was 81% in the pembrolizumab arm versus 70% with placebo, and median PFS was not reached in either arm.

Overall survival data were not mature at the time of PFS analysis.

Regarding safety, the most common adverse reactions occurring in patients who received pembrolizumab with CRT were nausea, diarrhea, vomiting, urinary tract infection, fatigue, hypothyroidism, constipation, decreased appetite, weight loss, abdominal pain, pyrexia, hyperthyroidism, dysuria, rash, and pelvic pain.

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    Mike Bassett is a staff writer focusing on oncology and hematology. He is based in Massachusetts.