Chicago (Reuters) - Bristol-Myers Squibb Co’s drug, Opdivo, improved survival in a trial of patients with the most common form of lung cancer, but it did not work in patients who tested negative for a specific protein in their tumors, leading to a nearly 7 percent sell-off in the company’s shares on Friday.
The Phase III trial found that Opdivo, part of a new class of drugs that harness the immune system to fight cancer, reduced by 27 percent the risk of death from advanced non-squamous non-small cell lung cancer (NSCLC), compared with chemotherapy. The benefit reached 60 percent for patients with the highest levels of the PD-L1 protein.
“Opdivo did not work in PD-L1 negative patients,” said Amit Roy, an analyst at research group Foveal. “That is nearly half of the non-squamous patients.”
He said many investors had expected that the drug might be effective regardless of PD-L1 levels, but the results indicate regulators would likely restrict usage to patients who test positive for the protein.
The Bristol drug was approved by U.S. regulators in December to treat advanced melanoma and competes with Keytruda from Merck & Co Inc. The current approvals for both drugs do not require testing patients for PD-L1.
Investors have been keeping a close eye on Opdivo’s performance in lung cancer, the most common form of the disease worldwide, and a far larger market. Opdivo was cleared in March to treat the less-common squamous type of NSCLC. Between 85 percent and 90 percent of all lung cancers are NSCLC, and more than two-thirds of those are the non-squamous type, according to the American Cancer Society.
Bristol shares fell $4.55, or 6.6 percent, to close at $64.60 on the New York Stock Exchange.
This latest trial, presented at the annual meeting of the American Society of Clinical Oncology, involved 582 previously treated patients with non-squamous NSCLC.
“This marks the end of the chemotherapy era in second-line treatment of lung cancer,” said Fouad Namouni, who oversees Opdivo development at Bristol-Myers.
He said the company is talking with the Food and Drug Administration about applying to expand approval for Opdivo, or nivolumab, to include advanced non-squamous NSCLC. Bristol is also studying Opdivo on its own and in combination with another immunotherapy called Yervoy as an initial treatment for lung cancer.
The trial results showed median overall survival of 12.2 months for the Opdivo group compared with 9.4 months for patients treated with docetaxel. For the subgroup of patients with high levels of PD-L1, which is used by tumors to evade the body’s defenses, median survival exceeded 17 months with Opdivo, compared with 9 months for chemotherapy patients.
One in 10 Opdivo patients in the trial experienced serious side effects, compared with more than half of patients in the chemotherapy group.
Roy said eventual use of rival immunotherapy drugs being developed by Roche Holding AG, AstraZeneca Plc and Pfizer Inc will also likely be restricted based on biomarker levels.
The ASCO conference also featured results from an early-stage study of Opdivo showing that 19 percent of patients with advanced liver cancer responded to the antibody with tumor shrinkage of more than 30 percent.
Researchers said that compares with a response rate of just 2 percent for Nexavar, the only currently approved systemic treatment for advanced liver cancer. Nexavar is produced by subsidiaries of Bayer AG and Amgen Inc
Editing by Andre Grenon