AstraZeneca's Imfinzi, chasing Merck's Keytruda in cervical cancer, flunks key trial

The roller coaster ride for AstraZeneca’s blockbuster cancer drug Imfinzi has taken a sudden dip, with a swing and a miss in cervical cancer.

On Thursday, the company said its phase 3 trial of Imfinzi combined with chemoradiotherapy failed to show that the drug could slow disease progression and extend the chance for survival better than chemoradiotherapy alone in locally advanced cervical cancer.

In this field, AZ had high hopes that Imfinizi could compete with Merck’s PD-1 superstar Keytruda, which gained a first-line nod in combination with chemotherapy for persistent, recurrent or metastatic cervical cancer last October.

Cervical cancer is the eighth most common and ninth most deadly form of the disease. It's seen few advances over the years as the chemoradiotherapy standard-of-care treatment has not changed in more than two decades, AZ said.

One plus from the Calla trial was that safety and tolerability were consistent between the study’s two arms.

“While the results were not what we hoped for, insights from the trial will advance our understanding and application of immunotherapy across our broad clinical development programme, exploring the benefits of Imfinzi in many tumour types,” Susan Galbraith, AZ’s executive vice president of oncology R&D, said in a statement.

The news comes after Imfinzi's success in a pair of recent trials. In one phase 3 study, Imfinzi—given after an initial dose of AZ’s maligned immune checkpoint blocker tremelimumab—helped those with unresectable hepatocellular carcinoma live longer than Bayer’s Nexavar.

In another phase 3 study, Imfinzi and chemotherapy helped advanced biliary tract cancer patients live longer and stave off disease progression longer than those on chemotherapy alone. It was the first time an immune-oncology regimen beat standard of care in front-line biliary cancer.

Imfinzi generated (PDF) $2.4 billion in sales last year, an 18% increase from 2020. The monoclonal antibody won accelerated approval to treat bladder cancer in 2017 and then gained subsequent approvals in unresectable stage 3 non-small cell lung cancer and extensive stage small cell lung cancer. Last February, AZ voluntarily withdrew its bladder cancer indication after a phase 3 trial failed to meet its primary endpoint in 2020.