April 25, 2012 | by WBadmin
PrEP not ready for prime time

By JAMES DRISCOLL, Ph.D.

Government picking favorites among technologies on the basis of politics is always risky.

Political favoritism that clears a regulatory path for marketing a new, incompletely tested, drug can cost lives.

Under pressure from Gilead Sciences and its AIDS advocate allies, the FDA antivirals advisory panel will soon consider accelerated approval for Gilead’s AIDS treatment drug Truvada for prevention of HIV infection. Opposition is widespread in the HIV advocacy and medical communities. AIDS advocates warn that such approval would be, at best, years premature. At worst, it would be an unwarranted, dangerous experiment with public health.

Clinical trial data supporting Truvada as prevention, or PrEP (pre-exposure prophylaxis), is weak and inconclusive.  PrEP is a far less effective preventative than are condoms (44% versus 98+% in U.S. conditions). Doctors fear that PrEP will be used instead of condoms or that its use will discourage condom usage. Cynthia Davis, an HIV doctor at Drew University of Medicine in Los Angeles, counsels that the drug must show 90 percent efficacy to be used safely in the U.S.

Davis worries that too many people will think that because they are taking the pill they will be safe. Dr. Kevin Fenton, CDC Chief of HIV-AIDS Prevention, has warned: “Some studies suggest that even a small increase in risk behavior due to a false sense of security about the pills’ effectiveness could actually increase HIV infections.”

Drug adherence among those already infected is difficult; it will be even more so among the uninfected. If the uninfected lack therapeutic levels of Truvada in their bloodstream before sex, they will remain unprotected. Patients will need careful monitoring and counseling to insure adherence; such handholding will be costly, inconvenient and in today’s economy unlikely.

Truvada is the most widely used anti-retroviral (ARV). Poor adherence, by the uninfected, will generate drug resistant viral strains. Curbing Truvada resistant strains is important to the well being of the HIV infected population and critical for those who become infected in the future.

ARVs are toxic, healthy people shouldn’t just pop them like vitamin C. The long-term toxicities of Truvada are unknown. Kidney damage, diabetes and hypertension have all been reported. Why risk these toxicities when safer, more effective prevention methods are readily available?

The NIH 052 study has proven that ARV treatment is 96+ percent effective in preventing infection of HIV-negative partners. Indeed, Science named 052′s results the No. 1 scientific advance of 2011.

Resources for ARV treatment in the U.S. are stretched to the limit. PrEP approval will result in scarce resources being diverted from proven preventatives that are 96+ percent effective into an experimental preventive which, even with ideal adherence, promises only 44 percent efficacy.

At $13,000/patient/ year retail, Truvada is a very expensive drug. In an era of severe fiscal constraints, Truvada used as PrEP would not only risk human lives, it would misallocate public and private resources needed for the healthcare of all Americans.

FDA Commissioner Margaret Hamburg has rebuffed appeals to meet with AIDS doctors and advocates who oppose accelerated approval for PrEP.  She is ‘too busy’ to listen to them about either the health risks of PrEP or the political influence on its behalf.  During the Clinton administration, Commissioner David Kessler met with AIDS advocates more than 20 times to discuss drug approvals.

Kessler’s door was open, he listened. Dr. Hamburg and her staff could learn from Dr. Kessler. One hopes the Obama White House can accelerate her learning curve — she appears to be stalled at go.

The FDA plays a crucial role in the fight against AIDS. When FDA listens to all AIDS advocates, it advances the solutions. If FDA closes the door to all but its friends, it becomes part of the problem.

President Obama has given America its first National AIDS Strategy, increased resources for HIV testing and ADAP, and sustained funding for international AIDS treatment in a difficult fiscal environment.

President Obama has listened and responded. The FDA needs to follow his example.

James Driscoll, Ph.D. is a longtime AIDS activist and an adviser to AIDS Healthcare Foundation.

2 Comments
  • Andrew Timleck

    Clarity is data is needed here – PrEP is effective ON AVERAGE 44% of the time – not 44% ALL the time, as the writer/writing here infers. It’s effective 73% of the time for those 90% adherent to meds and, admittedly, drops precipitously to 21% effectiveness when adherence drops below 90%. Yes it’s a political, economic, and possibly a health mess, but lets not bend the data propagandistically to make our point any more Gilead and others are bending it the other way to push it to market.

    Andrew Timleck, MPH, PhDc.

    Source: http://www.cdc.gov/hiv/prep/pdf/PrEPfactsheet.pdf

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