TreatmentUpdate41: Vol. 4, No. 1 - March, 1993
Sean Hosein

One of the problems with passive immunotherapy is securing a safe and effective source of antibodies. One group of researchers has decided to use pigs as a source of protective antibodies. Products from pigs, such as insulin, can be tolerated by humans. As a first step, the researchers injected pigs with several HIV proteins (such as gp120, gp41, p24 and p17). The pigs then produced antibodies against these viral proteins. In the second step, the researchers collected the pigs' blood and treated it to kill or inactivate any microorganisms. Later, the blood was filtered. The antibodies were extracted from the blood and tested for their ability to (1) attack HIV-1, (2) destroy HIV-infected cells and (3) prevent the clumping together of infected cells. The final product containing the pig's antibodies was called PASSHIV-1. Tests of this product have not detected HIV or other viruses in it.

Trial Details

Doctors in Denmark enrolled 14 HIV-infected subjects, most of whom were American men, into a study to test the safety and efficacy of PASSHIV-1. Before entering the study, most of the subjects had some symptoms caused by common infections such as yeast and bacteria. The average CD4+ count was 143 cells at the start of the study. Some subjects were taking AZT, others a combination of AZT and ddC and one took ddI. To prevent PCP all subjects took various anti-PCP drugs. The researchers gave the subjects 2 to 3 grams of PASSHIV-1 every day for 5 to 7 days. In total most subjects received 10 to 14 grams of PASSHIV-1. Some subjects received additional doses of the product.

Side Effects

One subject became sensitized to PASSHIV-1 and developed headache, fever, rash and pain. These symptoms cleared when the doctors stopped giving him the product. No other subject had any serious symptoms of toxicity.

Benefits: Laboratory Values

One subject had his CD4+ count increase from 122 cells before the trial to 375 cells 6 weeks later. Of 7 subjects who entered the study with low levels of platelets 3 had them return to normal levels. Three of 7 subjects who entered the study with low levels of white blood cells had them return to normal levels. Nine subjects had high levels of the enzyme LDH (lactate dehydrogenase) before receiving PASSHIV-1. In eight of these subjects LDH levels returned to normal and the remaining subject had his return to near normal levels. Three subjects with high levels of the liver enzyme alkaline phosphatase had them return to normal. PASSHIV-1 appeared to reduce levels of viral replication according to indirect measures (p24 antigen tests) of viral replication. There were no significant changes in CD4+ cell counts as a result of PASSHIV-1.

Benefits: Symptoms

All subjects had increased appetite, weight gain and reduced fatigue as a result of taking PASSHIV-1. Four subjects who had unexplained fever and 3 with night sweats became symptom-free and remained so for at least 4 months. Chronic yeast infections cleared as did pains in the feet and hands (peripheral neuropathy). Subjects with bacterial infections no longer required antibiotic treatments after receiving PASSHIV-1. Some subjects with Kaposi's sarcoma had a reduction in the size and number of lesions. The researchers will continue to monitor the subjects who will receive more PASSHIV-1.

This and other studies (see TreatmentUpdate 31) have shown that passive immunotherapy can provide benefit to some people with HIV-1 infection. The use of pigs may be one way to provide a safe and reliable source of anti-HIV antibodies. The authors suggest further testing of PASSHIV-1 in HIV-infected people. Doctors interested in this product may contact Dr. Kurt Osther, Verigen Inc., Hopkinton, Mass.

REFERENCES:

1. Osdler K, Wiik A, Black F, et al. PASSHIV-1 treatment of patients with HIV-1 infection: a preliminary report of a phase I trial of hyperimmune porcine immunoglobulin to HIV-1. AIDS 1992:6(12): 1457-1464.

2. Hohdatsu T, Pu R, Torres BA et al. Passive antibody protection of cats against Feline Immunodeficiency Virus infection. Journal of Virology 1993;67(4):2344-2348.

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Copyright © 1993 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284  http://www.catie.ca