U.S. health officials are investigating if a class of commonly used blood pressure drugs may increase cancer risk after a recent study raised concern.
An analysis of data from several clinical trials suggested medicines known as angiotensin receptor blockers (ARBs) "may be associated with a small increased risk of cancer," the Food and Drug Administration said in a statement on Thursday.
ARBs include Novartis AG's Diovan, Merck & Co Inc's Cozaar and Avapro from Bristol-Myers Squibb Co and Sanofi-Aventis SA.
The FDA said it had not yet determined if ARBs played any role in the cancer cases. The drugs provide significant benefit in patients with heart failure and high blood pressure, the agency added.
"FDA believes the benefits of ARBs continue to outweigh their potential risks," the agency said.
A study published in June in the Lancet medical journal examined data from more than 1,000 patients in several long-term clinical trials. The rate of new cancer cases was 7.2 percent for patients who took an ARB compared with 6 percent among patients who did not take one of the drugs. There was no difference in the rates of cancer-related deaths.
Most patients in the trials, 86 percent, took German drugmaker Boehringer Ingelheim's medicine, Micardis, which has annual sales of more than $1.5 billion.
The analysis had several limitations "that make it difficult to determine the validity of the findings" without a closer look, the FDA said.
Merck also said the type of analysis used in the study had limitations and the company "fully stands behind the tolerability and efficacy" of Cozaar.
Novartis reviewed four long-term clinical trials of Diovan using similar methods as the study published in the Lancet. Initial results showed no increased risk of new cancers for Diovan, a company spokeswoman said.
Bristol-Myers and Sanofi said "no signal for new cancers has been found" in the companies' ongoing review of health problems reported in patients treated with Avapro.
A Boehringer spokeswoman could not immediately be reached, but the company said in June its own analysis "contradicts the conclusions" of an increased cancer risk.
European regulators also are investigating a possible increased cancer risk with ARBs.