AEGiS-BAR: What's Up With Cytolin?

Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.

What's Up With Cytolin?

The Bay Area Reporter - February 20, 1996
Bill Thorne, ACT UP/Golden Gate Writers Pool

Much interest has been raised by a new approach to treating HIV infection called Cytolin; this article will provide an overview of the current status of clinical research into the drug. Since this therapy is in the earliest stages of investigation, most of the data has been presented by the company and its supporters. Although not intended as a complete scientific analysis, it is hoped that this snapshot of the current status of Cytolin research will clarify some of the questions which have been raised.

CytoDyn, the company with the patent on use of this therapy in HIV, was formed by HIV-positive individuals to address the hypothesis advanced by Dr. Allen D. Allen. These individuals decided to form a company, rather than seek a corporate sponsor, because they felt this would speed research. Subsequently, a relationship evolved with various physicians groups, including the AIDS reSEARCH ALLIANCE in Los Angeles. The reSEARCH ALLIANCE is a well-respected, community-based research group consisting of approximately 60 doctors in the Los Angeles area.

The one published article specifically dealing with Cytolin in humans involved only five HIV-positive homosexual males with CD4 counts of greater than 200. They were given infusions of 7 mg over a 20-minute period and followed for five weeks with extensive bloodwork, with some followed for as long as six months. The article appeared in Medical Hypothesis, a peer review journal, last year.

The hypothesis, very simply stated, is that administration of Cytolin, a mouse monoclonal antibody, can prevent a certain subset of CD8 cells from killing CD4 cells, thereby helping to stabilize an out-of-synch immune system. The study is considered a pilot study for future research directions for this therapy. Patients' CD4 cell counts remained essentially unchanged, but viral loads dropped an average of one log. There was also some improvement in delayed cutaneous hypersensitivity reaction ( an induced inflammatory skin test like the TB tine test).

Anecdotal reports have been good, including a patient cohort of 90 patients in San Francisco in which viral load reductions averaging about 50% were seen. Although promising, it must be remembered that the controlled study of Cytolin was only five patients, and therefore conclusions must be drawn cautiously.

CytoDyn spokesperson Dave Bianchi indicates that certain physicians' groups have been using the therapy on a compassionate use level, and that observational data has been collected and is being presented to the FDA currently for 188 patients. These doctors include some of the most well-known and respected in the field. He asserts that the company is committed to collaborating with the FDA to design a large, open-label dose ranging and pharmacokinetic study as quickly as possible. Additionally, the company has agreed to provide ACT UP/Golden Gate with information, including the information submitted to the FDA.

Bianchi wants to convey to interested parties that no firm conclusions regarding therapy can be drawn from the existing data, except a new direction for investigation of a potential therapeutic approach.

Questions have been raised by individuals in both the community and research establishment regarding the implications of interfering with the patients' CD8 cells. Concerns have been advanced about the possibility of complications with lymphoma and Epstein-Barr virus due to suppression of CD8 cells. CytoDyn claims the suppression of only one specific subset of CD8s occurs, and that this does not harm those cells or suppress other CD8s that would target lymphoma and Epstein-Barr.

It has also been questioned whether early animal studies performed on rats gave us sufficient information prior to human use. Bianchi asserts those tests were extensive and other animal models are not particularly relevant, because much safety data has been compiled and the substance does not appear to cause toxicity in most cases. One or two documented cases of allergic reaction were observed but resolved without intervention upon stopping the infusion.

Other side effects reported included flu-like symptoms with body aches, low grade fevers, and lymph node swelling - which resolved and can probably be prevented with administration of anti-inflammatory compounds such as ibuprofen and possibly antihistamines like Benadryl. Also observed in some patients were temporary depression, anxiety, and irritability. Concomitant use of other therapies such as antivirals and a failure to stratify the results has also been put forward as a criticism of the available data. However, community doctors report that success in the use of Cytolin is better in patients taking antivirals, and suggest that combination therapy is the way to go.

Obviously, many questions remain regarding the viability of Cytolin as a potential therapy. Only further study and open communication by all parties will resolve these concerns. A follow-up article in a few months will evaluate the situation at the time of the data analysis of the large, open-label, dose-ranging and pharmacokinetic study being planned. t

For more information regarding CytoDyn or Cytolin please contact the company directly at (213) 525-0560.

Call Out:

The hypothesis is that this mouse monoclonal antibody can prevent a certain subset of CD8 cells from killing CD4 cells, stabilizing an out-of-synch immune system.

ACTion UPdate

From February 28 to March 1, the Food and Drug Administration will hold hearings in Washington, DC to consider approval of three AIDS drugs. It will review scientific data on two new Protease Inhibitor drugs (Abbott's Ritonavir and Merck's Crixivan) and on Serono's Growth Hormone drug for AIDS-related wasting.

As part of the approval process, the public is invited to give personal testimony regarding these three drugs. ACT UP/Golden Gate will be sending representatives to these hearings and will have one of its members, Bill Thorne, sitting on one of the Review Panels. AU/GG is interested in hearing local public opinion of these three drugs.

If you have views on these drugs, we would welcome hearing your views. This information will be valuable, as we try to represent our community's views at the FDA.

Please send your written comments in care of Bill Thorne at ACT UP/Golden Gate, 519 Castro Street, Box 93, San Francisco CA 94114. t

ACT UP/Golden Gate meets every Tuesday at 7:30 at 592 Castro Street. Everyone is welcome.

ACT UP/Golden Gate is not affiliated with ACT UP/San Francisco.
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Always watch for outdated information. This article first appeared in 1996. This material is designed to support, not replace, the relationship that exists between you and your doctor.

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