Bristol-Myers Squibb Co. shares sank the most in a year as the effectiveness of the company’s lung-cancer drug was tied to whether patients had high levels of a protein on their tumors, potentially limiting the market for the treatment.
The stock slid as much as 7.6 percent, the biggest intraday decline since May 15, 2014. Analysts have projected the cancer drug, Opdivo, to be one of the company’s best sellers, with sales of $6.2 billion by 2020, according to estimates compiled by Bloomberg.
In a study of 582 patients with advanced non-squamous, small-cell long cancer -- the most common form of the disease -- patients taking Bristol-Myers’ Opdivo lived for a median of 12.2 months, compared with 9.4 months on the chemotherapy docetaxel. Patients in the study, released Friday, had already seen their cancer progress after earlier treatment.
But the results were more pronounced in patients with higher levels of a protein called PD-L1. That disappointed investors who expected Opdivo to show a consistent benefit across all patients.
“Bristol is saying we’re going to stay focused on the PD-L1 patient group,” said Asthika Goonewardene, an analyst at Bloomberg Intelligence, said. “They’ve had a change in tone.”
Patients who expressed PD-L1 on 1 percent or more of the cells had a median survival of more than 17 months, compared with nine months for similar patients in the docetaxel group.
The results may give Merck & Co. and Roche Holding AG an opportunity to more effectively compete against Bristol-Myers, since their cancer drugs have similarly been tied to PD-L1 expression, said Mark Schoenebaum, an analyst at Evercore ISI.
The study was released Friday at the American Society of Clinical Oncology’s annual meeting in Chicago.
Lung cancer is the leading cause of cancer death in the U.S. Worldwide, there are about 1.8 million new cases diagnosed each year and more than half are non-squamous, non-small cell. Opdivo was approved for rarer squamous tumors in March, three months ahead of schedule, and is also approved for melanoma.
Opdivo belongs to a class of drugs that trigger the immune system by blocking a cellular pathway known as PD-1, which otherwise restricts the body from attacking cancer cells.
The level of PD-L1, a related biomarker, in tumors can vary, and researchers have been attempting to determine whether PD-L1 expression levels can predict the drugs’ effectiveness. While the data may mean patients with less expression of the protein may not benefit as much from Opdivo, they also may give doctors a way to determine which patients are good candidate for the drug.
“This study is the first study that shows the role of PD-L1 expression as a predictive biomarker with Opdivo,” Fouad Namouni, Bristol-Myers’ head of development for the drug, said in a telephone interview. “In the field of biomarkers, and the field of lung cancer, it is a landmark study.”
Bristol-Myers is working with Dako, a unit of Agilent Technologies Inc., on getting FDA approval for a biomarker test that would more easily identify patients that could benefit.
“Even five years ago, an effective immunotherapy for lung cancer was largely considered impossible,” Gregory Masters, an attending physician at the Helen F. Graham Cancer Center and lung cancer specialist, said in a statement. “Today, we have such a treatment and it surpasses the standard therapy both in terms of efficacy and patient quality of life.”
Namouni said the company is in talks with the Food and Drug Administration but would not say when a decision on the expanded use might happen.