They attributed the drug's low abuse potential to the fact that it is slow to take effect and also because of the negative mood changes it sometimes produces.
In July 1999 the DEA granted Unimed's petition to reschedule Marinol from Schedule II to Schedule III. This action lifted many of the restrictions that previously limited Marinol's availability. Now physicians who prescribe Marinol in quantity or who specify refills face far less cumbersome paperwork than when the drug was listed in Schedule II. Not surprisingly, Unimed estimates that moving Marinol to Schedule III could produce a 15 to 20 percent increase in the drug's sales, currently estimated at $20 million (a modest figure by industry standards).
Beyond this important gain, Marinol's market could expand even further if the drug were approved for additional indications. Currently, 80 percent of the patients using Marinol take it to relieve AIDS wasting, 10 percent to relieve chemotherapy-induced nausea, and the remaining population for off-label conditions. The latter group is thought to consist mainly of Alzheimer's patients; in a recent study the drug showed promise in treating appetite loss and behavioral disturbances associated with that disease. Unimed cannot, however, market Marinol to treat complications of Alzheimer 's disease without first receiving FDA approval.
The company is currently conducting research in pursuit of approval for this indication and in late 1998 received a use patent for the application of Marinol to improve disturbed behavior in people with various forms of dementia, including Alzheimer's disease. This gives Unimed 20 years of patent protection for dementia treatments based on its product provided that the additional indication gains FDA approval.
Another likely market for Marinol consists of people with AIDS who receive combination antiretroviral therapy (see Chapter 5). For these patients dronabinol offers a double benefit: not only does the drug stimulate appetite, it also appears to relieve nausea and vomiting, common side effects of the standard daily doses of antiretroviral drugs. Unimed is presently conducting a Phase II study in this area; if the results are promising, the company plans to seek FDA approval for the additional indication.
In addition to possible applications for Alzheimer's and AIDS patients, Unimed—along with its marketing partner, Roxane