Hepatitis C is the insidious bad-boy of the hepatitis-causing viruses. Unlike its liver-loving cousins hepatitis A and B, a slow-acting, virtually symptom-free chronic hepatitis C infection can eventually cause life-threatening liver complications in 20% and death in about 5% of those infected. Documented cases of hepatitis C have been traced back half a century, yet until its isolation in 1989 hepatitis C infection was termed "non-A non-B" hepatitis by default. With a diagnostic test for hepatitis C came evidence that HIV and hepatitis C coinfection was actually quite common, yet only in the last four years have AIDS researchers and clinicians started to pay serious attention to the implications of dual infection. Since it can take twenty to forty years for hepatitis C to cause clinically significant liver damage, most clinicians initially presumed that individuals with both HIV and hepatitis C would die of AIDS before liver disease became a concern. Now that people with HIV are living longer due to better therapies, the long-term management and treatment of people with HIV/HCV coinfection has emerged as a crucially under-researched issue.

At this year's Retrovirus Conference, a three-hour symposium and many data presentations were devoted to hepatitis C research. Two big-name presenters at the symposium were David Thomas and Mark Sulkowski from Johns Hopkins University. Brilliant young Turks of hepatitis research, Thomas and Sulkowski have contributed greatly to our fledgling knowledge of the epidemiology, natural history and response to treatment of hepatitis in those with HIV/HCV coinfection. Their lectures were eagerly awaited by the numerous HIV clinicians in the audience not yet familiar with all aspects of disease progression and clinical management of HIV-infected individuals with hepatitis C.

Thomas noted that a recent CDC study estimated 4 million persons nationwide are hepatitis C antibody positive and about three million of those are chronically infected with hepatitis C (meaning they have a detectable HCV viral load). This could mean that about 1.8% of the U.S. population is HCV-positive. Although we do not know the total number of those coinfected with HIV and hepatitis C, it is clear that hepatitis C prevalence is very high among injecting drug users. The problem for inner-city methadone and HIV/AIDS clinics is staggering-often more than half the clients have HIV and hepatitis C. One Baltimore methadone clinic reported a HIV/HCV coinfection rate of 97%.

Unlike hepatitis A and B, only 20-30% of people who have hepatitis C will experience any symptoms (namely, jaundice, nausea, and fatigue). Doctors rarely test for hepatitis C and thus do not recognize the presence of infection. Thomas and his colleagues at Hopkins documented many previously untested injection drug using patients who tested HCV-positive upon entering their study during follow-up in their natural history study, even though most were regularly seeing a doctor who failed to recognize any of the signs and symptoms of hepatitis C.

People who have any history of injection drug use should be tested for hepatitis C because they are likely to have been exposed. An epidemiology study (again, from Johns Hopkins) estimated that the risk of acquiring hepatitis C infection was as high as 65% for new injectors within six to twelve months of beginning injection drug use; by two years it was almost 90%. The risk of acquiring hepatitis C from injecting drug use is much higher than from other viral infections such as HIV. The same study documented the rate of HIV infection in injection drug users during this short window was only 14%.

Thomas also stated that having HIV gives a poor prognosis for one's hepatitis C infection, and that those with coinfection are at increased risk for liver disease progression. I differ with Thomas on this conclusion. The out-of-date data he presented were from cohorts of HIV-infected patients (mostly hemophiliacs) obtained before the widespread use of highly active antiretroviral therapy (HAART). HIV-infected patients who had worse liver disease than their HIV-negative counterparts in the late 1980s and early 1990s had high HIV loads and CD4 cell counts below 200. Today, effective anti-HIV drugs allow much better control of HIV, which can result in increased CD4 cell counts (and improved immune function). This may mean that individuals with suppressed HIV who have hepatitis C can fare just as well as those without HIV.

This was shown in a French study published last year. Yves Benhamou and colleagues from Paris reported on liver fibrosis progression (the liver deterioration process) in a well-characterized HIV/HCV coinfected cohort. Low CD4 counts (<200 cells/mm³) and more than five glasses of alcohol (50 grams) a day were shown to be associated with a higher liver fibrosis progression rate leading to cirrhosis (end stage liver disease). When they analyzed all patients by CD4 count above or below 200 cells and by alcohol consumption, there was little difference in the time from hepatitis C infection to cirrhosis between the HCV+/HIV+ co-infected individuals and the matched HCV+/HIV- control groups.

For example, for someone with a CD4 cell count below 200 who drank more than five glasses of alcohol a day, progression to cirrhosis would be expected in an average of fifteen years. But for someone who drinks less and has over 200 CD4 cells, the estimated time to cirrhosis is 36 years. This is very close to the 40-year estimate for an HIV-negative person who is not a heavy drinker.

The same researchers also presented some good news at this year's Retrovirus Conference about coinfected individuals on protease inhibitor therapy. Originally, the study was done because researchers worried that protease inhibitors would do damage to the HCV-positive patients' livers. In fact, the opposite was shown. Those on protease inhibitors for approximately one year who had CD4 counts above 200 had a slower progression to liver disease than those not on protease inhibitors. (Note: they did not look at the non-nuke class of drugs such as efavirenz or nevirapine).

What do the findings from this study tell us?

1. It is safe for HCV-infected patients with HIV to take protease inhibitors.
2. HCV-related liver disease complications are reduced when co-infected individuals keep their CD4 counts above 200.
3. Heavy alcohol consumption is bad for one's liver. We still don't know how much alcohol is too much. One beer or glass of wine may not hurt your liver, but more than five glasses a day might not be a good idea.

What about sexual transmission of hepatitis C?
Many gay men want to know if hepatitis C is sexually transmissible, especially those who decide not to use condoms. It's a controversial subject where no two hepatitis researchers agree. For monogamous couples who only have vaginal intercourse, the risk appears slim to none. However, there are some convincing reports that men who have sex with men with numerous sexual partners who engage in high-risk behavior are at increased risk for becoming HCV-positive. Likewise, those with sexually transmissible disease and people with HIV and hepatitis B may be more likely to transmit hepatitis C to their partners. While it appears there must be blood-to-blood contact, the risk of hepatitis C transmission among high-risk individuals may be as high as 15%. The accompanying table summarizes fourteen epidemiology studies from around the world which have documented man-man sexual contact, sexually transmitted diseases, and other risk factors for transmitting hepatitis C.

A Canadian study presented at the conference reported that gay men with HIV had a higher incidence of hepatitis C than their gay, HIV-negative counterparts. Importantly, the act of "fisting" was found to be the only sexual practice associated with an increased risk for hepatitis C infection.

Treatment of HIV and HCV coinfection
For some years in the 1990s the recommended treatment for hepatitis C was alpha interferon. The current standard of care is a combination of interferon with ribavirin. The combination of interferon and ribavirin has been shown in clinical studies to be superior to interferon alone. Unfortunately, all people with HIV were excluded from the original studies of this dual combination for hepatitis C. Douglas Dieterich and colleagues from New York conducted a trial to determine if interferon/ribavirin combination therapy was safe and effective in HIV-positive individuals with hepatitis C. Although the trial results appear promising for those in the combination group, we cannot be certain that combination therapy was more effective than interferon alone because patients were unevenly randomized into the two treatment arms. Importantly though, the interferon/ribavirin combination appeared safe for people who were also on HAART. Side effects, such as depression, flu-like symptoms and anemia (low red blood cell count) were no more prominent in the combination group than in the interferon group.

A few concerns about the safety of ribavirin in HIV-positive people linger. There is a possibility for increased toxicity, including hemolytic anemia (destruction of red blood cells), and a potential adverse interaction between ribavirin and certain anti-HIV drugs, particularly AZT, 3TC, and d4T. Ribavirin potentially decreases the intracellular activation of these three nucleoside analogues-although some early data suggest that this interaction may not be clinically significant. More studies are needed to address these concerns.

A longer lasting pegylated formulation of interferon is currently in clinical trials. The two companies, Hoffmann-La Roche and Schering Plough, have different pegylated interferons. Both appear to be more effective than regular interferon and need only be given once a week, rather than the 3-5 times a week current dosing schedule. Although the less frequent dosing makes them easier to take, the pegylated interferons are no gentler than-and the side effects are similar to-regular interferon.

Slowly we are learning how to manage and treat individuals with HIV and HCV coinfection, but much remains to be done. More research money and a strong commitment from the National Institutes of Health (NIH) and the pharmaceutical industry is badly needed to continue this progress. ¤

This year, TAG joined the Alliance in calling upon NIH to double funding for microbicide research from its current $13 million a year level. Members of TAG accompanied the Alliance to a meeting with Dr. Anthony Fauci at the National Institute of Allergy and Infectious Diseases for this purpose. TAG has also worked to communicate the importance of this prevention strategy. In 1998 TAG sponsored a community forum in New York City with Dr. Polly Harrison from the Alliance. TAG has also pushed to have microbicide advocacy efforts featured at the National AIDS Treatment Advocates' Forum. TAG's new Antiviral Project Director, Yvette Delph, reports from a recent Washington forum.

The NIH "Microbicides 2000" conference was held in Washington, D.C., on March 13-16, 2000. The over 600 participants included 275 international registrants from 40 countries. The Office of AIDS Research (OAR) plans to publish the conference proceedings and post them on the web (www.nih.gov/od/oar).

The 20-hour conference covered virtually the entire landscape on vaginal microbicides, from basic science and animal models to clinical trials and behavioral science. A major weakness, however, was inadequate attention to the rectal use of microbicides. There was a mere one-hour concurrent session on "non-vaginal microbicide use." No one would dispute the urgent need for women-controlled methods for the prevention of sexually transmitted infections (STIs), including HIV, and the pressing need to expedite research in this area and to get a safe, effective product on the market; however, failure to study the drugs in development for rectal use ignores the many women who practice rectal intercourse and the men who have sex with men.

Michael Gross of Abt Associates, Inc. noted that HIVNet VPS2 found a 32% prevalence of at least one act of anal intercourse in the preceding six months among 1,400 high-risk women using audiocomputer-assisted self interviewing. We have to assume that any topical vaginal microbicide that is marketed will be used rectally. Rectal safety and efficacy studies of topical microbicides should be done concurrently with vaginal studies.

Ashley T. Haase, of the University of Minnesota Medical School, looked at the early stages of SIV infection following vaginal inoculation. On Day 1, there was no evidence of viral replication. By Day 3 there was some viral replication limited to the cervix, which increased 7-fold by Day 7. By Day 12, viral replication had spread systemically except for the central nervous system (CNS). In early infection, T cells seem to be the predominant cells supporting viral replication. Macrophages are not infected in large numbers, but they play a crucial role in priming T cells so that they are activated and go on to become infected and replicate virus. The infection of quiescent CD4 T cells helps to maintain an unbroken chain of transmission. Haase concluded that there may be a narrow window of opportunity after initial inoculation for preventing the systemic spread of the virus

Ronald Roddy and Zeda Rosenberg of Family Health International provided an overview of microbicides currently in development. There are six products undergoing in vitro screening, twenty-five in rabbit vaginal irritation studies, twenty-eight in animal toxicology, about twenty in Phase I clinical trials, three in Phase II, and four in Phase III: Nonoxynol-9 (N-9) sponge, N-9 film(VCF), N-9 gel (Advantage-S and Conceptrol) as well as five completed Phase III trials since 1990.

Products in development include:

1. Surface active agents: N-9 in new formulations, N-9/octoxynol-9/benzalkonium chloride (BZK)/sodium cholate(NaCh) combinations, C31G (amphoteric surfactant), sodium dodecyl sulfate (SDS), and chlorhexidine gel;
2. Enhancers of normal vaginal flora: Lactobacillus suppositories, acid buffers (ACIDFORM, BufferGel), peroxidases, antibiotic peptides (magainins, protegrins-both naturally occurring-and gramicidin), monoclonal antibodies (plantibodies);
3. Inhibitors of viral binding/ entry: Sulfated polymers (dextran sulfate gel), cyanovarin-N, gp41 fusion inhibitor (T-20);
4. Viral inhibitors: UC-781 (NNRTI-thiocarboxanilide), tenofovir (PMPA), nevirapine, loviride (loviridine), AZT derivatives, bicyclams.

There were several reports of N-9 causing vaginal and rectal inflammation and raising concerns that such inflammation may impair the mucosal barrier function-enhancing rather than reducing transmission of infectious organisms. Deborah Anderson of Harvard Medical School noted that daily vaginal application of Conceptrol (N-9 100 mg) for three days resulted in sloughed epithelial cell sheets and a dramatic influx of polymorphonuclear cells two days after the last N-9 application. She reported findings from a study of N-9 induced cytokine release from normal vaginal and cervical epithelial cell cultures. The findings suggest that N-9 induces vaginal inflammation via IL-1 a, which acts on neighboring cells to activate NF-KB, which in turn triggers the typical inflammatory cascade.

Gregg N. Milligan of Children's Hospital Medical Center (Cincinnati) used a mouse model to examine the influence of N-9 application on infiltration of inflammatory cells into the vagina. The number of white blood cells (WBCs) was four-fold greater at 4 hours and continued to increase significantly (p<0.05) by 8 hours in N-9 treated mice compared with placebo controls. Application of preparations containing 4% N-9 resulted in greater numbers of infiltrating WBCs than did preparations with lower concentrations of N-9. Up to 50% of the infiltrating WBCs were macrophages, and there was no significant increase in lymphocytes. The vaginal inflammatory response began to resolve by 24 hours after a single N-9 treatment.

David Phillips of the Population Council (New York) presented a study comparing the effects of rectal application of N-9 (KY-Plus and Foreplay) and two non-N-9 containing formulations in each of four subjects. Rectal lavages collected thirty minutes after the application of N-9 revealed sheets of epithelium. This was not seen in any of the baseline or non-N-9 lavages, nor in the lavages at 10-14 hours after N-9 application.

Connie Celum of the University of Washington also looked at the toxicity of rectal N-9 and found minimal epithelial toxicity at the 52.5 mg dose, but sampling was done several hours after N-9 insertion. This would suggest that N-9 may cause rapid mucosal exfoliation which is fully repaired within 14 hours. More studies need to be done with larger numbers of subjects.

William Donohoe of the Magee-Women's Research Institute presented a poster of a study of the susceptibility of ten strains each of Lactobacillus, Neisseria gonorrhoea and Trichomonas vaginalis to thirty minutes of exposure to N-9. All ten strains of Lactobacillus and 7/10 of Neisseria survived, and all ten of Trichomonas were killed.

Several participants expressed concern about the wisdom of continuing N-9 clinical trials, especially one funded by UNAIDS, until the safety of N-9 as a microbicide has clearly been established. Echoing these concerns, Lut Van Damme of the Institute of Tropical Medicine in Belgium noted that of five completed N-9 studies, two were observational studies that suggested a protective effect. However, there were three randomized, controlled trials (RCTs): one in Kenya in 1985 which showed that N-9 was harmful; one in Kenya in 1988 of STDs only, which failed to show any effect (the study was too small to analyze the effect on HIV transmission); and one in Cameroon in 1997 which showed no effect on gonococcal or chlamydial transmission. Christine Rouzouix (Hôpital Necker-Enfants Malades, France) and Robert Coombs (University of Washington) dealt with the male and female genital compartments, respectively, noting that viral load in blood plasma correlated with viral load in seminal plasma (RR=0.56, <0.0001) and in the female genital tract (RR=0.6, p<0.01). Steven Taylor presented a poster of a study comparing seminal antiretroviral drug concentrations with concurrent blood concentrations. Indinavir reaches concentrations in semen that are not significantly different from blood concentrations, whereas ritonavir and saquinavir seminal concentrations are <5% those in blood. Nevirapine semen levels were >60% of corresponding blood levels. Lamivudine (3TC) concentrations in semen were 5-10-fold higher than those in blood and stavudine (d4T) had similar seminal and blood concentrations-although several patients on d4T had seminal and blood concentrations that were below the limit of detection of the assay.

Finally, some of the issues related to the design and conduct of microbicide trials included: the difficulty collecting data relating to compliance; the dilemma over whether analysis should be conducted based on compliance levels; the difficulties posed by the use of a placebo, since any product used intravaginally may have an effect and the production of placebo formulations can prove challenging; and the use of other STIs as surrogates for HIV. Some of the ethical concerns included: the effect of microbicide use on male condom use; how best and how intensely to counsel about condom use; the need to promote the use of the male condom in trials of the female condom-although both can not be used simultaneously; the meaning and extent of informed consent; whether male partners should be asked to consent; whether and, if so, how antiretroviral therapy should be provided for women found to be HIV-positive at screening or for seroconverters; and the impact of microbicide research on research on other barrier methods (condom, diaphragm, cervical caps). ¤

This article was written by the most recent addition to the TAG staff, Yvette Delph, who became the new Antiviral Project Director in January 2000. A medical doctor and native of the Caribbean, Yvette has worked extensively in HIV/AIDS and Women's Reproductive Health. She comes to TAG from the National Minority AIDS Council, where she was the Director of Treatment Education, Training and Advocacy. Please see www.treatmentactiongroup.org for more information on Yvette.

Haseltine was talking about CCR5, the gene for the second receptor HIV needs (after docking to the CD4 molecule) to penetrate human cells. The company stumbled upon the CCR5 gene during its mass sequencing of the human genome. They applied for and later received a patent on the gene sequence covering its use as a receptor and potential receptor antagonist. Meanwhile, most of the researchers who actually established CCR5's role in HIV infection were left out in the cold. In fact, if any of them have ideas about developing drugs that target this protein or gene for therapeutic use, they'll have to deal with Haseltine and Human Genome Sciences. Gregg Gonsalves reports.

The case of the CCR5 gene brings up thorny issues in biomedical ethics, intellectual property rights, and patent law. Who owns the human genome? The first gene patents were granted on sequences that code for known human proteins with clear physiological or therapeutic effects. Later, in the early 1990s, the National Institutes of Health, under the leadership of Bernadine Healy, applied for thousands of patents on little snippets of DNA called expressed tag sequences (ESTs) without any knowledge of their function. These patents were withdrawn after an outcry by the scientific community, but industry quickly stepped in and began applying for millions of patents on ESTs. Craig Venter, the NIH researcher who developed EST technology, then entered the private sector, forming Celera Inc., and joined Haseltine and Human Genome Sciences in a now dissolved gene-hunting and database-searching partnership.

The more radical view on gene patents decries any commercialization of the human genome whatsoever, maintaining that genes and their mutations are naturally occurring substances that should not be patented. Jonas Salk, when asked years ago in an interview with Edward R. Murrow about who owned the rights to the polio vaccine, replied, "Well, the people, I would say. There is no patent. Could you patent the sun?" Those who oppose any patents on DNA would extend Dr. Salk's proposition to the human genome.

The United States Patent and Trademark Office has granted a few patents on ESTs, but recently has begun to reëvaluate the wisdom of its EST-based gene-patenting policy. Recent statements from U.S. Patent Office Director of Biotechnology, John Doll, has indicated that patents on genetic material will need to demonstrate "some substantial, real world utility" before they can be approved. Currently, most EST patents are sitting in limbo.

Unfortunately, information that establishes this "real world utility" may be curiously general. It can result from a database search that simply identifies a gene or gene fragment as part of a larger family of known genes. The National Institutes of Health objects to this drift in U.S. Patent Office (USPTO) policy, saying it doesn't go far enough. Former NIH director Harold Varmus and current National Human Genome Research Institute director Francis Collins recently wrote the Patent Office asking for more stringent standards that would demand elucidation of a gene's specific physiological function before granting a patent.

From TAG's perspective, the NIH's position makes more sense than the USPTO's or that of the DNA sequencing industry. While TAG has its disagreements with the NIH, here we find common ground. Allowing patents on ESTs with only a vague, accompanying theoretical function, based on database findings rather than pathophysiological research, favors companies that have invested their resources in the simply mechanical task of churning out potentially active DNA sequences. This will create monopolies on the human genome that could impede research on AIDS and other diseases, especially the development of new therapies.

We don't need a new Microsoft for the biological software of human genes. We have already heard of researchers foregoing critical experiments on CCR5 inhibition rather than risk conflict with Human Genome Sciences' alleged patent rights. What other havoc are companies like Human Genome Sciences and Celera going to wreak on drug discovery research in the future? If the U.S. Patent Office doesn't change its standards and require established physiologic functions before granting gene patents, Congress should change the relevant patent law or find other ways to protect researchers and small companies from these genetic robber barons. We should reward those who invest their time and resources in the difficult scientific work of figuring out the function of human genes and proteins. And we should protect those who use this knowledge to develop new ways to diagnose, treat and cure disease.

There are additional difficulties in this emerging world of patented genetic information, with fragmented and overlapping intellectual property rights' having the greatest potential to stymie drug development efforts. Rather than rush to judgment on gene patenting, the Patent Office, Congress and other relevant institutions need to consider a wide range of issues before crafting regulation and legislation in this area. The stance of those who would ban gene patenting altogether may seem attractive in light of anticipated difficulties in negotiating this public policy minefield, but in the end reflects a flawed utopian view. If incentives for the commercialization of products derived from genetic research are removed, the development of a new generation of treatments, including treatments for HIV, will certainly be slowed. It will be a challenge for policymakers and researchers to strike the proper balance that maximizes incentives for competition in the interest of public health. ¤