FDA Antiviral Drugs Advisory Committee
met earlier this month (November 6-8, 1995) to review approval applications for Roche’s protease inhibitor saquinavir (trade name Invirase ), Glaxo-Wellcome’s 3TC (lamivudine, trade name Epivir ) and Bristol’s d4T (stavudine, trade name Zerit ). The committee recommended approval for Roche’s saquinavir for use in combination with other nucleoside analogs (e.g., AZT, ddC etc.), paving the way for saquinavir to become the first HIV protease inhibitor licensed for sale–at an annual price rumored to run in excess of $5,000. The committee also recommended approval for Glaxo’s 3TC–for use in combination with AZT. Bristol’s d4T, already licensed, was recommended for full approval. Next month’s TAGline will feature a comprehensive report of the 3-day proceedings.
Ambushed in the FDCs
A recent paper in the journal Nature provides evidence to support the “bad trapping” phenomenon believed to occur in the germinal centers of the follicular dendritic cells (FDCs) of lymph nodes. The mechanism depicted in the research (and accompanying editorial by Fauci et al.) shows how otherwise disarmed antibody-and-complement-coated HIV is rendered re -infectious by the FDCs via an as yet elucidated mechanism. Since these germinal centers of the FDCs are a major conduit and “meeting place” of CD4+ T cells, uninfected T cells unwittingly fall prey to HIV trapped in the FDCs in what has been likened to a viral ambush.
Expanding T cells: Koenig weighs in on Good CTLs/Bad CTLs debate
Researchers at MedImmune Inc. report that an expanded CD8+ CTL clone, directed against the HIV-1 nef protein, produced a dramatic rise in p24 antigen levels and an unexpected and persistent decline in immune function when infused back into the HIV-positive donor. And in a recent issue of the Journal of Infectious Diseases ((vol. 172, 1:88-96), Harvard researchers Bruce Walker and Cara Wilson reported their success in growing CD4+ T cells from HIV-infected patients, establishing “the feasibility of CD4+ T lymphocyte expansion in persons with HIV.”