A potentially life-saving treatment for HIV may never get out of the lab. For years scientists have known about a cancer drug that might work in a fundamentally new way against AIDS. But the companies and the U.S. government that jointly own the drugs can't get their act together to test them.
In 1993, Dr. Arthur Pardee and his colleagues at the Dana Farber Cancer Institute tested a "topoisomerase I inhibitor" named topotecan, to see if this drug might be good against HIV.
These scientists showed topotecan, which is already used to fight ovarian cancer, stops a critical part of HIV, called the LTR of the virus, from working. The study concluded that a very small amount of topotecan, hundreds of times less than the amount used in fighting cancer, might stop HIV. Dr. Pardee assumed topotecan would be tested on volunteers with HIV. These tests never happened.
Topotecan is currently marketed by Glaxo SmithKline under the brand name Hycamtin. More recently, the FDA approved other topo I inhibitors like Camptosar, marketed by Pharmacia & Upjohn as a treatment for colorectal cancer and is expected to approve a third, Rubitecan, which will be marketed by Abbott Laboratories for pancreatic cancer.
None of the companies intend to test their topo I inhibitors to see if they work against HIV. Some companies have suggested the drugs might be too toxic for use in patients with HIV. But these drugs are already used in patients with cancer.
Perhaps the real reason why drug companies aren't developing topo I inhibitors for AIDS treatment, was best stated by Abbott Laboratories. Abbott is unwilling to develop their version, Rubitecan, as an HIV drug because the government owns the patents. Since the government has some say over the prices that could be charged for the medicine if it is used for HIV, there is reluctance to spend lots of money developing the drug without knowing how much the company would be allowed to charge for it.
By 1997, it was clear these topo I inhibitors would not get developed by the big drug companies for HIV illness. So the federal government gave an exclusive right to a small company named Virologix. Nothing happened. In 1999, Virologix was bought by a company named Access Pharmaceuticals.
Access could not get cooperation and support from the companies that make the topo I inhibitors. So, eight years after it was clear these drugs might help people with HIV, nobody has tested them. Someone needs to pay attention and take action.
The NIH should test these drugs on behalf of all people with HIV. Or, use its enormous leverage to convince the pharmaceutical industry to conduct trials of these topo I inhibitors.
What nobody should do is ignore a new potentially powerful drug against HIV while people who have used up their options are dying.
Dr. Alfred DeMaria, Assistant Commissioner of Communicable Disease, Massachusetts Department of Public Health and Dr. Arthur Pardee of the Dana Farber Cancer Institute reviewed and commented upon this article.