WASHINGTON, D.C. Food and Drug Administration (FDA) officials have given Agouron Pharmaceuticals the green light to market the company's new HIV protease inhibitor, Viracept (nelfinavir mesylate), in this country under the FDA's accelerated approval process clause.
Nelfinavir is the first HIV protease inhibitor to be cleared for marketing in both adult and pediatric forms, company officials said.
"The approval of Viracept is important for the field of HIV disease,'' said William Powderly, MD, of Washington University's School of Medicine in St. Louis. "The anti-HIV potency of Viracept, coupled with its safety and tolerability, will make a valuable contribution in our ability to hit the virus hard and early with combination therapy.''
Nelfinavir is used for the treatment of HIV infection where antiretroviral therapy is warranted. Results of the drug's trial runs were presented in January by several investigators at the Fourth Conference on Retroviruses and Opportunistic Infections in Washington, D.C.
In the presentations, calculated reductions of HIV in plasma (viral load) were based upon a branched DNA amplification (bDNA) analysis involving measurements of HIV to lower limits of either 500 copies/mL or 100 copies/mL. In reviewing nelfinavir data, the FDA determined that the values below 1,200 copies/mL could not be reliably quantified by the bDNA analysis and required that calculated reductions in viral load be based upon a lower limit of 1,200 copies/mL in the nelfinavir package insert.
In clinical studies, more than 1,000 patients who used nelfinavir for 24 weeks at the recommended dose of 750 mg, taken with reverse transcriptase inhibitors zidovudine (AZT, Retrovir, Glaxo Wellcome) plus lamivudine, (3TC, Epivir, Glaxo Wellcome), experienced a 98% mean reduction in viral load after six months, (1.7 log10) using a lower limit of 1,200 copies/mL. At the conference, this six-month value was reported as 99% (2.0 log10) and >99% (2.5 log10) based upon lower limits of 500 copies/mL and 100 copies/mL, respectively. Currently, there are no results from controlled trials evaluating the effect of nelfinavir on clinical progression of HIV, such as survival rates or the incidence of opportunistic infections.
Last August, the company began safety and tolerability tests on 38 HIV infected children ages 1 to 13. Initial trials have proven the drug to be safe for the children but tolerability level tests are continuing, company officials said.
Doctors said the most common side effect observed was severe diarrhea, which the test subjects eventually controlled through over-the-counter medications.
Company officials said they plan to make nelfinavir available to all AIDS Drug Assistant Programs (ADAP), including those purchasing products through government-discounted pricing. It will also offer rebates to any ADAP unable to purchase products at government-discounted rates. The cost of nelfinavir is about $16 a day or $5,600 for a year's supply at the recommended three-times-a-day dose of 750 mg.
To facilitate easier access to the drug, Agouron has set up an assistance program to help HIV patients find ways of paying for their treatment. The company will provide nelfinavir without charge to those whose need is deemed greatest but who cannot afford the drug. Children not covered by their parent's public or private health insurance will also be covered for the treatment's costs by the company, Agouron officials said.
For more information:
- Viracept Assistance Program, call Agouron Pharmaceuticals at 888-777-6637.
- Powderly, W. The efficacy of Viracept in pivotal phase II/III double blind randomized controlled trials as monotherapy and in combination with d4T or AZT/3TC. Fourth Conference on Retroviruses and Opportunistic Infections. Jan. 22-26. Washington, D.C.
- Krogstad, P. Phase I study of the HIV protease inhibitor nelfinavir mesylate (NFV) in HIV-positive children. Fourth Conference on Retroviruses and Opportunistic Infections. Jan. 22-26. Washington, D.C.
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