New cancer drugs might help treat HIV — but research not done
John S James, for AIDS Treatment News
A new class of cancer drugs — topoisomerase inhibitors — is now in use in the United States for treating certain cancers. But despite laboratory studies and other reasons to believe that these drugs might also work as antiretrovirals, they have never been tested in people for treating HIV.
An activist who investigated the situation found that the US government owns the rights to use at least some of these drugs for HIV, and licensed exclusive rights to a small company that was unable to get funding to start human research. And the big companies that are selling the drugs for cancer are not interested in testing for HIV — either because of the exclusive license, or for other reasons. Similar licensing problems could be blocking development of other drugs that we have not heard about.
AIDS activist Eric Goldman investigated this situation and published a short article in the current issue of Positively Aware.
“An HIV Treatment the World May Never See,” by Eric Goldman with David Scondras, Positively Aware March/April 2002,
The current organisation of AIDS medical research makes it very difficult to get a new drug into the first human testing, to establish a proof of principle that it might work. Industry is reluctant to do this — not so much because it is expensive (industry does pay for the large clinical trials needed for drug approval, which cost much more), but because the reward is too distant. Once there is positive human data, it is much easier to raise money and interest for further research.
The case of topoisomerase inhibitors is unusual in that these drugs have gone through the entire approval process for cancer. Therefore, the first human trial for HIV would be much less expensive, since formulation, tolerable dosing, toxicity, and some long-term safety issues have already been worked out. Still this work wasn’t done, and no one is doing it today.
Since these drugs are already in use, it would be quick and easy to see if there were an effect on viral load in persons treated for cancer who also happen to have HIV. If a major reduction in viral load could be documented, it would be much easier to get further research started. Then the next step could be a small trial in which the drugs were prescribed for selected patients.
The first topoisomerase inhibitors are given by injection, but a new one — Orathecin, formerly named Rubitecan — now waiting for FDA approval for pancreatic cancer, is taken orally. All can have serious side effects. It is not known whether smaller doses could be used in HIV treatment. Indeed, since the research has not been done, no one knows whether these drugs, in any doses, could have any value in treating HIV.
We also need more investigation into the problems in licensing policies and elsewhere that block early human research that would be strongly in the public interest. As Goldman points out in his article, there may not be any single villain in this story — each company and government agency may have done what it was supposed to do. Lack of a villain can make it harder to mobilise public interest for reform. Still, the system is not working — and is costing many lives, if any of the drugs that should have been tested would in fact be useful.
As a lawyer who works in intellectual property in the entertainment industry, Goldman had the background to be among the first to investigate the complicated tangle of legal rights that has blocked these drugs and probably others from being tested as they should. Now that he has shown the way, other activists without this specialised background can help develop the investigation.
A major problem in AIDS treatment today is that many patients need new drugs, and the “pipeline” of potential new antiretrovirals is disappointing. The biggest single block in the pipeline — the obstacles to the small human trials that could establish proof of principle —needs much more attention.
Source: AIDS Treatment News Issue #379, April 12, 2002. Copyright
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