Lilly’s promising drug for breast cancer runs into problems in Japan

One of Eli Lilly and Co.’s fastest-growing new drugs, Verzenio, a treatment for metastatic breast cancer, is running into a spate of safety problems with Japanese patients that raise questions about the drug and could possibly hurt sales.

The Japanese health ministry warned May 17 that the drug is suspected of adversely affecting patients’ lungs, after 14 recipients in Japan developed a serious lung disease and three died, according to the Japan Times. The drug is suspected of causing that problem in at least four of the 14 cases, including one fatality, the ministry said.

Indianapolis-based Lilly said Monday it has updated the label for Verzenio in Japan to include a new warning following reports of the adverse drug reactions there. The updated label warns of the risk of interstitial lung disease/pneumonitis, a group of disorders that cause scarring of the lungs and can make it difficult to breathe for some people.

Lilly said patient safety is its top concern and it is taking steps to monitor the drug closely.

“It is known to be more frequently observed in an East Asian population, and the majority of cases reported for Verzenio worldwide have been in Japan,” Lilly said. “The reason for higher incidence of noninfectious pneumonitis in this population is not fully understood, though differences in genetic sensitivity may play a role.”

Lilly began selling Verzenio in Japanese in November, two months after getting regulatory clearance there. More than 2,000 patients in Japan have used the drug since then.

A major setback with Verzenio could chip away at Lilly’s aggressive push into oncology, potentially a huge growth area where it has long been a mid-tier player. In the past year, Lilly has spent nearly $10 billion to acquire oncology companies to boost its cancer pipeline. The company ranks ninth globally among drugmakers for oncology sales, far behind leaders Roche, Celgene, Bristol-Myers Squibb and Novartis.

Eli launched the drug, its first-ever cancer drug in tablet form, in the United States in September 2017, more than a year before it began selling it in Japan. Verzenio rang up worldwide sales of $255 million last year, a more than tenfold increase over the previous year. Lilly did not break out sales in Japan.

Verzenio competes against two other drugs, Pfizer’s Ibrance and Novartis’ Kisqali. All three drugs belong to the same class—called CDK inhibitors—which work by blocking overactive enzymes that would otherwise allow cancer cells to proliferate. The drugs are prescribed for women with a type of breast cancer called HR positive/HER2 negative, where the cancer has spread to other parts of the body.

Verzenio’s main selling point is that it is the only one of the three CDK inhibitors on the market that is approved for daily use—twice a day, every day—to try to fight the tumors. The Pfizer and Novartis drugs are approved only for intermittent use, as needed.