New AIDS Drug Likely to Be OKd Today : Health: DDI will be the second medication sanctioned for use against the disease. FDA approval being given despite lack of knowledge of effectiveness.
Federal health officials are expected to announce today that they have approved the AIDS antiviral drug DDI, making it the second such drug to be licensed since the 1987 approval of AZT.
DDI--also known as dideoxyinosine and didanosine--would provide an alternative treatment for the thousands of AIDS patients who cannot medically tolerate AZT. For now, the drug’s use would be limited to adults or children who cannot take AZT, which causes serious side effects, or for whom AZT has been ineffective, sources said.
An antiviral drug attacks the underlying viral condition--in this case the human immunodeficiency virus that causes AIDS--rather than the infections, cancers and other conditions that result from the damaging effect of HIV on the human immune system.
The approval is scheduled to be announced at a press conference this morning at the Department of Health and Human Services. A simultaneous announcement of approval is expected today in Canada.
The action represents a milestone in the drug approval process.
Regulators at the Food and Drug Administration decided to license the drug based on early scientific evidence that they hope will prove to be a reliable predictor of the drug’s ultimate effectiveness, which is still unknown.
The move occurs in a new regulatory climate in which efforts are being made to speed up the availability of drugs that treat such critical conditions as AIDS and cancer.
The approval is based on studies showing that DDI apparently increases the number of CD 4 cells, also known as T4 helper cells, compared to patients who were taking AZT. CD 4 cells are the critical immune system cells that are the primary target of the virus. Once these cells are destroyed, AIDS symptoms typically appear.
Like AZT, the drug works by inhibiting the infection of new immune system cells by the virus.
Traditionally, a drug such as DDI would not be approved until tests have shown more conclusive evidence of long-term effectiveness.
It is still unknown, for example, whether DDI will prolong survival, as compared to deaths among those not taking the drug or taking another drug, such as AZT; whether it will provide longer periods free from the infections that characterize the disease, compared to those not taking the drug; or, in the case of HIV-infected individuals without symptoms, whether it will provide a significantly longer time before progression to disease.
The drug, which is manufactured by Bristol-Myers Squibb Co., will be marketed under the trade name Videx.
Dr. Robert T. Schooley, an AIDS researcher who has studied the drug, described it as “well-tolerated” by a majority of patients with advanced HIV infection. “They have an improvement in their feelings of well-being and their CD 4 cells rise,” he said.
“At this point, we are making a drug much more widely available on the basis of much more limited clinical information than has ever been done in the past. (That) marks a significant departure for the FDA, which, under the circumstances, I think is good,” added Schooley, who heads the infectious diseases division of the University of Colorado Health Sciences Center.
