It is taking longer for new drugs to get approved by U.S. drug regulators. But while aspersions have been cast at the Food and Drug Administration as the main source of the delays, drugmakers should shoulder some of the blame.

One of the newer theories floating around about why drug regulators seem to take their sweet time is that drug companies are filing inferior applications. If the data submitted in the application are spotty or don't address issues likely to be raised in the review process, the FDA has little choice but to return the application or reject it altogether.

If this is true, drug companies should be spending a lot of time and money making sure their regulatory staffs are up to snuff. Unfortunately, says Merrill Lynch analyst Steven Tighe, the quality of new drug applications sent to the FDA seems to vary widely.

Tighe covers the pharmaceutical industry, so he and his colleagues looked back six years to analyze approval times and rejection rates. The best performers were Merck ( MRK) and Eli Lilly ( LLY), which got their drugs approved in an average time of 10.9 months and 11 months, respectively. The average review time for Bristol-Myers Squibb ( BMY), Schering-Plough ( SGP) and Pharmacia ( PHA) ranged from 14.6 months to 15.6 months.

Alas, American Home Products ( AHP)and Pfizer ( PFE) brought up the rear of the rankings, with slothlike average review times of 19.8 months and 25.5 months, respectively.

Lost Time Means Lost Money

This is not just an academic exercise. Remember, time is money. By Tighe's reckoning, a one-month delay in a drug's approval equals $41.7 million in lost revenue. So in the past six years, Pfizer has lost a whopping $7.7 billion more than Lilly has due to drug-approval delays, according to the Merrill Lynch analysis.

Now, there are some extenuating circumstances that affect drug-review times, Tighe cautions. For starters, the FDA grants some drugs accelerated-review status, which means decisions are usually reached in 6 months. In 1999, 54% of new drug applications were granted such priority reviews, which pushed down the median review time for the year. But in 2000, only 33% of drugs were granted priority review.

And certain classes of drugs are given more attention at the FDA. AIDS and cancer drugs, for instance, tend to be reviewed faster because of the urgent medical need. At the other end of the spectrum, drugs focused on women's health, such as contraceptives, take the longest to work through the FDA because the need is less, says Tighe, adding that Pfizer develops a relatively large number of women's health drugs.

This variability makes it a bit difficult to judge the future performance of the drug companies, based on their historical records. But for the record, Merck has had one drug, a new antibiotic for bacterial infections, sitting at the FDA for the past 10 months. Lilly has already received tentative approval for its osteoporosis drug, Forteo, less than a year after submission.

Meanwhile, Pfizer has three drugs submitted to the FDA in 1997 and 1998 that are still awaiting decisions.