MERCK's PROSTATE DRUG DEVELOPMENT PROGRAM: PROSCAR STATUS REPORT
The following exchange between Merck Chairman Vagelos and financial analysts summarizes the current status of the development of MK-906 (Proscar) for prostatic hypertrophy. The prostate drug development program has been the darling of the financial markets in recent weeks. This Q&A exchange exhibits that interest clearly. The exchange, in fact, started the open-floor portion of Merck's November 3 appearance before the New York Security Analysts and took up about one-quarter of the full Q&A period. This transcript was prepared by "The Pink Sheet" from an official tape recording of the session. Merck officials have not had the opportunity to edit or review the transcript prior to publication. The questions have been paraphrased with key quotes noted. Q: Proscar looks like it may be Merck's next "megaproduct." Could you tell us something about the worldwide patient population that might be applicable? And how it will fit into existing therapies? Will it displace, or augment them? A: The question is whether Proscar will be a major drug. That, of course, cannot be determined until we have finished our Phase III. The way we see it developing is that we know that men -- only men by the way -- age 50 and above start having prostate enlargement. ]The occurrence frequency[ is about 30% at age 50, and it increases with age. So, by age 70, the majority of men have prostate enlargement and a very significant number of these people will have an obstruction to urine flow, which causes them to need an operation. And the current treatment is only operation, surgical scraping of the prostate which has a fair amount of debilitation that goes with it. ]The surgical procedure has[ a very low mortality, very low, on the order of 1% or less, which is probably an anesthetic type of mortality rate. And ]surgery[ works, but there are all kinds of potential complications. If one could take a drug to reduce prostate size that would be a very significant product. It would be taken by many men once it is proven to be safe. It will be taken by many men over age 50 because the incidence of enlarged prostate is so high. The studies thus far show that the drug does the job; it doesn't do it in all patients. No question. And I would tell you that we have started, of course, as we normally do, in the most severe cases. So it is the toughest test. And what we see is that some 25-30% of patients get measurable reduction in prostate size and we have very significant numbers with an improved urine flow. We see that in the worst cases. Our plan is to continue to expand the people who are being tested on the drug and to ask the question that, if one starts with the beginning of prostate enlargement, what percent would respond to this kind of therapy? Clearly, the way it works is that this is another Merck enzyme inhibitor. It blocks the enzyme that causes the conversion of testosterone to dihydrotestosterone. It is dihydrotestosterone which causes the prostate to enlarge. Research has already figured out what the dose is, which is of the order of 1-5 mg., once per day. And we are starting Phase III. If it continues to look safe and if the efficacy is what we think it should be, we will certainly have a significant drug. Q: Will it be taken as a maintenance drug? A: The answer is yes. We already know that patients who have responded to the drug and stopped the drug to have enlargement again. So it is a hormonally responsive enlargement, and that is why we are so anxious to start in people at an earlier stage of the disease. It will be taken for life. Q: Have you studied Proscar in combination with Vasotec or cardiovascular products to see if there are problems if you use two together? A: The answer is no. Some of those patients may be on drugs, but we have done no studies because we are too early ]in clinical development[. We certainly will be doing all kinds of studies of that sort because it is an older age group drug and these people will necessarily be on some of our other drugs. ]However,[ the doses are very low and the drug is very specific. It goes to this one enzyme. And, unless dihydrotestosterone interferes or is involved in some cardiovascular effects, I would guess there will not be major problems. Q: Could you describe the sort of Phase III protocol in terms of time that would seem to be required? How long does it take for the drug to show a "discernable" response? Have you talked to FDA for their view of a drug like this in terms of potential 1A status? A: Research has talked with the FDA. They have had an end-of-Phase II conference. The reaction was very positive. The response to the drug of course, is a rolling response. You certainly see a response within 12 weeks, and this response continues to increase. So it is relatively early. The ]other part of the[ question was what kind of a Phase III program would we have -- and we just don't discuss that. We're not ready to discuss that. Q: What adverse effects have you seen up through Phase II and also in long-term animal tox work? A: We haven't seen any adverse reactions from Phase II. And animal toxicology is ongoing, of course, because it is early. Thus far the things that we have seen are the things that you would anticipate from a drug that cuts off dihydrotestosterone. In other words, it is a teratogen. It has to be, because you are cutting off a hormone that is required for the formation of a normal penis. So, if you don't have a penis yet, you shouldn't be on this drug.
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