A new kind of potential treatment is about to begin its first human trial in San Francisco.

A drug called Z-100 (also called Ancer 20) has been approved for years in Japan and used by thousands of patients there to stimulate growth of blood cells after cancer therapy; doctors use it when filgrastim (Neupogen®) would be used in the U.S. The drug, prepared from the cell walls of the bacterium that causes tuberculosis and injected in very small amounts, stimulates the production of many cytokines in the process of causing blood cell growth -- and has been found to increase the production of MIP-1-alpha, which can help block many HIV variants from entering cells, in laboratory tests with cells from patients with HIV.⁽¹⁾ It appears to change the immune response from Th2 toward Th1, which may be useful in controlling this virus.

Laboratory tests with HIV found that Z-100 alone did not reduce the growth of the virus -- but did reduce viral growth when combined with a concentration of AZT which was too low to be effective in itself.⁽²⁾ These studies are only suggestive, because patients usually respond differently than cells in a laboratory culture.

The first study of Z-100 as a possible HIV treatment will soon start at the University of California San Francisco Medical Center. It will test Z-100 alone (without antiretrovirals) in volunteers who are either antiretroviral-naive, or off antiretrovirals for at least 16 weeks, and whose CD4 count is between 300 and 800. Their viral load must be between 2,000 and 50,000 copies, and they must pass usual safety tests (liver enzymes, etc.). Volunteers will be randomly assigned to take either 20 micrograms or 40 micrograms of Z-100, or placebo, for 8 weeks, followed by four weeks followup. There are no plans currently for providing Z-100 after this trial.

Side effects of this drug are usually minor, mostly at the injection site.

Comment

Volunteers should not expect personal benefit from this trial, except from the laboratory testing that will be provided. No one can predict whether this treatment will work at all for HIV, or whether it will have any antiretroviral activity if not combined with AZT or other drugs. What is important is that this study is testing a new approach to HIV treatment -- one which could readily be applied if it is found to be helpful, since the drug already exists and has been extensively used in patients.

For More Information

To find out more about this trial, patients or doctors can call either Anna Smith, R.N. at 415-476-9296 ext 313, or Brad Hare, M.D., at 415-514-0550 ext. 360.

References

1. Suzuki F., Kobayashi M., Curry J., and others. The induction of macrophage inflammatory protein (MIP)-alpha by Z-100, a M. tuberculosis-derived arabinomannan, in cultures of peripheral blood mononuclear cells (PBMC) from patients with HIV infection. Abstracts of the General Meeting of the American Society for Microbiology, May 30 - June 3, 1999 [abstract V-30].

2. Sasaka H., Nomoto K., Pollard R.B., and Suzuki F.M. tuberculosis-derived arabinomannan (Z-100) enhances the anti-HIV activity of zidovudine (AZT) in cultures of human peripheral blood mononuclear cells. Antimicrobial Agents and Chemotherapy. 1998; September 24-27; 38:368 [abstract I-18].

ISSN # 1052-4207

Copyright 2001 by John S. James. Permission granted for noncommercial reproduction, provided that our address and phone number are included if more than short quotations are used.

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