In a setback that could spell trouble for several drugmakers developing a new type of diabetes pill, U.S. regulators have told partners Bristol-Myers Squibb Co. and AstraZeneca PLC they can't approve its experimental drug without more data.
Shares of both companies fell more than 2 percent.
The Food and Drug Administration decision Thursday comes after expert FDA advisers in July recommended that dapagliflozin not be approved. They cited elevated rates of bladder and breast cancer seen in clinical studies, plus concerns about infections and possible liver damage.
Bristol-Myers has been touting dapagliflozin as an important new drug. BernsteinResearch analyst Dr. Tim Anderson had forecast sales of about $1.2 billion a year by 2020, a modest blockbuster by today's standards.
Dapagliflozin is part of a new class of drugs for Type 2 diabetes called SGLT-2 inhibitors, which reduce blood sugar by increasing how much is excreted in the urine and also help patients lose weight. Type 2 diabetes, which is generally related to obesity and a sedentary lifestyle, accounts for at least 90 percent of diagnosed cases in adults.
Bristol-Myers, based in New York, and London-based AstraZeneca said the FDA wants data from ongoing studies and may require new ones to better evaluate the drug's benefits and risks. If that happens, it likely would delay a chance at approval by a couple of years.
The companies said they'll work with the FDA to determine their next steps and are committed to dapagliflozin, which has been tested in more than 5,000 patients in 19 clinical studies. The companies also are in "ongoing discussions with health authorities in Europe and other countries" where they are seeking approval for the once-a-day pill.
The setback follows failures of other experimental drugs for each company recently and could indicate difficulties ahead for several other competitors developing compounds similar to dapagliflozin, according to Anderson.
"Our best guess is that safety concerns linger over the small cancer signal that surfaced in prior studies," Anderson wrote.
Bristol and AstraZeneca both need some new big sellers soon because they have blockbusters facing generic competition this year and in future years.
Blood thinner Plavix, which Bristol jointly markets with France's Sanofi SA, is the world's second-best-selling drug but loses U.S. patent protection this May. Bristol reported $5.42 billion in Plavix sales in the first nine months of 2011, part of which goes to Sanofi. AstraZeneca loses patent protection in March for its No. 3 drug, Seroquel for schizophrenia and bipolar disorder. It brought the company $3.2 billion in the first three quarters of 2011.
Anderson noted he expects Bristol-Myers to have flat revenue from 2012 onwards and that AstraZeneca seems "to have a never-ending decline."
If it's approved eventually, dapagliflozin would have to fight for space in the increasingly crowded field of diabetes drugs, which now spans about a half-dozen classes of pills and injected drugs, plus multiple types of insulin. Numerous older pills are available as cheap generics, so newer ones must be significantly better and safer to win insurance coverage and market share.
Bristol's Onglyza, another type of drug for Type 2 diabetes launched 2 1/2 years ago, has been a disappointment, with sales of only $320 million in 2011's first nine months.
Bristol-Myers, which has one of the industry's best portfolios of drugs in development, said last month that experimental liver cancer drug brivanib didn't increase overall survival in a late-stage study. Three other late-stage studies of that drug are continuing.
Late last year, AstraZeneca said it was abandoning plans to develop a new ovarian cancer drug called olaparib, and that a planned antidepressant known as TC-5214, being developing with U.S.-based Targacept Inc., did not perform well in the first of four late-stage studies. Further tests of TC-2514 were continuing, though.
In early afternoon trading, AztraZeneca's U.S.-listed shares were down 69 cents, or 1.4 percent, at $47.51 and Bristol-Myers shares declined $1.08, or 3.2 percent, to $32.65, while the broader markets were up less than 1 percent.