WASHINGTON -- The Food and Drug Administration's approvalon Wednesday of the AIDS drug ddI broke new ground and maychange the future development, approval and regulation ofdrugs for fatal diseases.

The agency approved Bristol-Myers Squibb Co.'s ddI(dideoxyinosine) for use by patients who cannot tolerate AZT,which is the only other approved AIDS therapeutic, or arefailing to respond to AZT therapy.

Both drugs, plus the not-yet-approved ddC (dideoxycytidine),are nucleoside analogs that inhibit the replication of viralgenetic material.

Unprecedented steps taken to rush ddI to market "pushed theenvelope of drug development and review," FDA CommissionerDavid Kessler said. The approval process was shortened to 180days from the normal 20 months or more.

Kessler said that the approval is part of a general effort tospeed drug approvals. He said the FDA is taking a similarapproach to speed approval of ddC.

The FDA based the ddI approval on data from Phase I safetytrials and very preliminary Phase II data. And for the firsttime the agency based approval on "surrogate markers," in thiscase a reversal of the decline of CD4 cell counts, rather thanmore traditional clinical end points, such as survival.

Other unique aspects of the ddI approval included closecooperation among the FDA, the National Institutes of Health,and the Department of National Health and Welfare of Canada,where the drug was simultaneously approved. The fast trackalso included the simultaneous approval for pediatric patientsand an "expanded access" program for patients outside clinicaltrials.

The FDA and Bristol-Myers created a special expanded accessprogram that allowed more than 23,000 patients to take thedrug before any trials had been completed. Phase I trials wereconducted in parallel with the program.

Three Phase II/III trials are under way to determine theefficacy of ddI as an independent treatment, as a follow-on incases of AZT intolerance or failure, and in combination withAZT. Bristol-Myers has agreed to remove the drug from themarket if the trial data, expected next spring, do not proveclinical efficacy.

A one-year supply of ddI, trade-named Videx, will cost lessthan $2,000, according to the company.

The U.S. government will get a 5 percent sales royalty becausethe compound was developed at the National Cancer Institute.

-- Steve Usdin BioWorld Washington Bureau

(c) 1997 American Health Consultants. All rights reserved.