ASTRA’s DALGAN DRUG ABUSE POST-MARKETING STUDIES

ASTRA's DALGAN DRUG ABUSE POST-MARKETING STUDIES should include a joint proposal by other makers of opioid agonist-antagonist analgesics, FDA's Drug Abuse Advisory Committee recommended at its June 5 meeting. "The five companies that are involved are going to take a crack at some of the [Phase IV] studies, hopefully with some input from the FDA division of epidemiology and NIDA [National Institute of Drug Abuse]," said committee chairman Theodore Cicero, PhD, Washington University School of Medicine, St. Louis, Missouri. Other companies involved are DuPont, Bristol-Myers Squibb, Sterling and Norwich Eaton. DuPont representative William Schmidt remarked: "We are very willing and eager to participate in the design of a study like this." DuPont is the manufacturer of the injectable analgesic Nubain (nalbuphine). Other opioid agonist-antagonist analgesics include Bristol-Myers Squibb's Stadol, Sterling's Talwin, and Norwich Eaton's Buprenex. The latter two drugs are scheduled. Although Astra is the only company which is required to conduct the post-marketing studies under an agreement made with FDA prior to the approval of Dalgan in December ("The Pink Sheet" Jan. 8, In Brief), FDA is encouraging the other companies to participate. Wyeth-Ayerst developed Dalgan (dezocine), licensing the drug to Astra following its approval. "I think that all five companies should be involved, because even though right now you may not feel that there is going to be any fallout from this that effects you, there is a definite possibility [that it will] and I think you would want to put your two cents in throughout the process," commented FDA Pilot Drug Evaluation Staff Director John Harter, MD. "I think our basic goal is to try to develop a policy that will be as effective as possible to the proper use of these drugs and is effective in preventing the abuse of these drugs," Harter said. Last August, FDA asked the committee for its advice in developing clinical guidelines for drugs with abuse potential. However, the committee opposed firm guidelines for study of such drugs ("The Pink Sheet" Aug. 14, p. 4). Several possible approaches to post-marketing studies were outlined by DuPont's Schmidt. "One would be to use a computer analysis of sales data where the data could be broken down between zip code or sales territories," Schmidt suggested. The system would be easy to implement at a minimal cost, he pointed out, and "the information is generally available from manufacturers on computers anyway." A second approach would be an epidemiological study of the abuse potential among healthcare professionals. "We have an armchair estimate that we would probably have to survey 10,000 out of perhaps 200,000 healthcare professionals who might have access to these drugs," Schmidt remarked. Among the problems of such a study are physician cooperation and verification, Schmidt noted. However, one of the major problems of an epidemiological study is the cost, which DuPont estimates could exceed $100 mil. A third option for post-marketing studies would be drug testing, which Schmidt maintained would be more effective in identifying abusing physicians at a lesser cost to companies. However, several panel members pointed out that these compounds are not detectable by current drug screening techniques. "The routine monitoring is not looking at these compounds and they are definitely going to be missed," said Sidney Schnoll, MD, Medical College of Virginia. "The companies would have to come up with ways of testing for these compounds and somebody is going to have to pay for this," Schnoll remarked. FDA agreed with the committee that the abuse studies should target health professionals primarily, since the diversion and abuse of opioid agonist-antagonist analgesics by patients is less frequent. For example, of 87 incidences of misuse or abuse of Nubain reported to DuPont between June 1979 and June 1990, Schmidt said, "47 can be directly attributable to healthcare professionals." Some reports indicate that up to 10% to 20% of anesthesiologists may be abusing a controlled substance, Schmidt said.