Bulletin of Experimental Treatments for AIDS, No. 30; September, 1996
Harvey S. Bartnof, MD, Leslie Hanna and Liz Highleyman

A more extensive conference report may be found on the BETA Web Page at http://www.sfaf.org/beta.html.

The XI International Conference on AIDS was held in Vancouver, British Columbia July 5-12, 1996. It was the largest of its kind since the first international AIDS conference in Atlanta in 1985. There were a record 14,137 registered attendees from over 125 countries, and 5,252 abstracts were presented. The conference was divided into 4 concurrent themes: Basic Science, Clinical Science (including treatment), Epidemiology and Public Health, and Social Science: Research, Policy and Action.

The conference was marked by cautious optimism regarding the beneficial effects of new combination therapies for HIV. That optimism was balanced against the reality that over 90% of the world's HIV positive people will never receive those therapies because they live in developing nations that lack adequate resources. Other main themes included: (1) the clear value and importance of HIV viral load testing in a variety of clinical settings; (2) nutrition and wasting; (3) alternative therapies; and (4) women's issues, particularly research into vaginal microbicides. A new theme at this year's conference was treatment for early HIV infection.

Part I: Clinical Updates and Basic Science

**Viral Load Testing

The clinical benefits and utility of HIV viral load testing were demonstrated in numerous presentations. HIV viral load was a topic in 213 abstracts. This year and this conference will undoubtedly be remembered for the unequivocal establishment of HIV viral load testing as part of HIV/AIDS care in developed countries.

**Predicting HIV Progression And Survival

The value of HIV viral load in predicting the future course of HIV/AIDS progression and survival was expanded and demonstrated in several different groups of patients.

* Gay/bisexual men

John Mellors, MD, from the University of Pittsburgh, expanded his group's research on viral load and disease progression from the Pittsburgh arm of the Multicenter AIDS Cohort Study (MACS) to the entire 4 city study. The update included 1,064 HIV positive antiretroviral-naive men. (See also BETA, June 1996, pages 9-10, 41-42.) The most commonly shown slide at the conference was the Mellors group's graph demonstrating increased progression to AIDS and death with increasing baseline HIV viral load.

Those HIV positive men who entered the MACS with a baseline RNA viral load of greater than or equal to 30,000 copies/mL had a 13-fold increased relative risk of progression to AIDS over 10 years, and an 18-fold increased risk of death, when compared with those who had less than 500 copies/mL at baseline. Those who entered with a baseline viral load between 500-3,000 copies/mL had only a 2.5-fold increased risk of AIDS progression or death over 10 years, when compared with those with a baseline viral load under 500 copies/mL.

Mellors provided new analyses indicating that higher baseline HIV RNA viral loads predicted a greater annual CD4 cell decline. For example, those with a baseline HIV viral load less than 500 copies/mL lose a mean of 36 CD4 cells/mm3 annually. Those with a baseline viral load greater than 30,000 copies/mL lose a mean 76 CD4 cells/mm3 annually. There were intermediate annual CD4 cell losses in those with baseline viral loads between 500-30,000 copies/mL.

Mellors cautioned that the exact RNA copy numbers from the MACS study are likely to be 30-50% lower than would be expected due to the use of heparin-containing tubes and processing delays when the blood samples were drawn in 1984-1985.

Five other gay/bisexual male cohort studies reported correlations between baseline viral load, HIV disease progression and mortality. Those studies included: San Francisco Men's Health Study, the Swiss HIV Cohort Study, the Vancouver Lymphadenopathy AI

DS Study, CPCRA 007 and NuCombo. The Swiss HIV Cohort Study found that in late stage HIV disease (AIDS), CD4 cell count is a better predictor of death, while HIV plasma viral load is a better predictor of HIV progression.

* Women

The ALIVE study from Baltimore included women, and 26% of the Swiss HIV Cohort are women.

* Injection drug users

The ALIVE study from Baltimore is comprised of injection drug users(IDU).

* Hemophiliacs

The Multicenter Hemophilia Cohort Study data was presented by Thomas O'Brien, MD, MPH, from the National Cancer Institute. The study was also published in the July 10, 1996 issue of the Journal of the American Medical Association. In addition, a report from Japan confirmed similar observations among hemophiliacs there.

* Infants and children

Lynne Mofenson, MD, from the National Institutes of Health, presented data demonstrating the predictive value of HIV viral load in infants and children infected during pregnancy and delivery. In children under age 1 year, HIV viral loads tend to be higher than in adults, with averages approaching 1 million copies/mL. Also, after initial infection, there is a much slower decline of viral load to the "set-point" in this group, when compared with adults. The set-point reached a plateau at age 2-3 years, whereas adults establish their set-point within 6-12 months after infection. Since enrollment in 1988-1991, only 3% of those with a baseline RNA level under 5 log copies/mL died, while 13% of those with levels between 5 and 6 log died, and 33% of those with a baseline over 6 log died.

Elaine Abrams, MD, from Harlem Hospital Center in New York City, reported that the HIV RNA viral load in infants at age 2-3 months was an excellent predictor of clinical outcome and death. A viral load above 1 million copies/mL (6 log) at age 2-3 months predicted a 50% mortality by age 1 year. She stated, "Effective interventions to lower viral load may therefore need to be initiated during infancy."

William Shearer, MD, from Texas Children's Hospital, reported that higher HIV RNA plasma viral loads in infancy were correlated with faster HIV disease progression in 102 infants from the Women and Infants Transmission Study. Shearer found that viral load peaked at 1-2 months of age for the infants.

Increased maternal viral load near the time of delivery also was found to be associated with rapid HIV progression in the infant when transmission did occur, according to a presentation by Jeremy Weedon, PhD, from Medical and Health Research Associates in New York City.

Abrams EJ and others. HIV viral load early in life as a predictor of disease progression in HIV-infected infants. Oral presentation and abstract We.B.311.

BETA 9-10, 41-42. June 1996

Craib KJP and others. Post-seroconversion HIV-1 viral load predicts progression to AIDS and death among seroconverters in a prospective study of homosexual men. Late breaker presentation and abstract Mo.C.902,

Galetto-Lacour and others. Prognostic value of viremia in patients with long-standing human immunodeficiency virus infection. The Journal of Infectious Disease 173:1388-1393(Swiss). June 1996.

Graham NMH and others. Infectious HIV viral load predicts clinical progression and survival among HIV infected adults. Oral abstract We.B.411.

Lambert G, Weedon J and others. The effect of maternal CD4 count, AIDS and viral load on disease progression in infacts with perinatally acquired HIV-1 infection. Poster presentation and abstract We.C.3461.

Mayers DL and others. Viral burden measurements in CPCRA 007. Late breaker presentation and abstract Th.B.911.

Mellors JW and others. Prognostic value of plasma HIV-1 RNA quantification in seropositive adult men. Oral presentation and abstract We.B.410.

Mellors JW and others. Prognosis in HIV-1 infection predicted by the quantity of virus in plasma. Science 272:1167-1170. May 1996.

Mofenson LM and others. Relationship between serum HIV-1 RNA copy number and mortality in HIV-infected children followed in the NICHD IVIG clinical trial. Oral presentation and abstract We.B.315.

O'Brien TR and others. HIV-1 RNA levels in early chronic infection: association with AIDS and long term non-progression. Oral presentation and abstract Mo.C.323.

O'Brien TR and others. Human immunodeficiency virus type-1 serum RNA levels and time to AIDS in the Multicenter Hemophilia Cohort Study. Journal of the American Medical Association 276(2):105-110. July 10,1996.

Schearer WT and others. Prospective evaluation of plasma HIV-1 RNA copy number in 106 HIV-infected children from the Women and Infants Transmission Study. Late breaker presentation and abstract Th.B.910.

Sheppard HW and others. Determinants of long-term non-progression: the relative contribution of viral burden and strain variation. Oral presentation and abstract Mo.A.390.

Yerly S and others. HIV viremia influences survival in HIV infected patients. Oral presentation and abstract We.B.413.

Yamamoto Y and others. A decade of HIV-infected hemophiliacs: low virus burden in non- and slow progressors of HIV infection in 1985. Poster presentation and abstract Mo.B.1259.

**Diagnosis of HIV Infection

* HIV RNA viral load may be the best way to diagnose HIV infection in infants and seroconverters

* RNA viral load tests turn positive before antigen, antibody or DNA PCR tests

Teresa Brown, MD, from the Centers for Disease Control and Prevention(CDC), presented a report indicating that HIV RNA viral load tests become positive before any other HIV tests in infants, including DNA tests using polymerase chain reaction (PCR). Due to the fact that a positive RNA viral load test represents active replication (transcription) of the virus, it may also be more specific than other tests. Positive HIV antibody tests in infants often reflect maternal antibodies that crossed the placent a during pregnancy. Thus, a positive RNA viral load in an infant may represent active and true HIV infection. However, this would not rule out the possibility of subsequently "clearing" the virus and the "seroreversion" that has been documented in a few HIV-infected infants.

Michael Busch, MD, PhD, from Irwin Memorial Blood Center in San Francisco, also reported on the order in which HIV blood tests turn positive, using stored samples from 376 adult seroconverters. The results were similar to Brown's report. Busch reported that RNA viral load tests become positive 3-4 days before p24 antigen and DNA PCR tests become positive. Five days after that, the first screening antibody test becomes positive.

These results indicate that the first test to turn positive is the RNA viral load test. This information has direct application for diagnosing people during their acute (primary) HIV infection with flu-like symptoms, diagnosing newborns, and even screening the blood supply and organ/tissue donors. Nonetheless, the p24 antigen test is less expensive than a viral load test.

Brown TM and others. Early diagnosis of perinatal HIV infection comparing DNA-polymerase chain reaction and plasma viral RNA amplification. Poster presentation and abstract Tu.B.2374.

Busch M, Schumacher RT and others. Consistent sequential detection of RNA, antigen and antibody in early HIV infection: assessment of the window period. Oral presentation and abstract Tu.A.153.

**Measuring Response To Anti-HIV Therapy

* Correlation with HIV progression

* Measuring HIV viral load in lymph organs

Several presentations documented that the decrease in HIV viral load due to the use of HIV therapies statistically correlates with a decrease in disease progression. A few showed that the same decrease in viral load correlates with increased survival. Those studies include ACTG 175 (disease progression or death); NUCA 3001 and 3002 (disease progression), VA 298 (disease progression), Delta 1 (disease progression) and CPCRA 007 NuCombo (disease progression or death). David Katzenstein, MD, of the ACTG 175 study, reported that for every 1 log copies/mL reduction in HIV RNA viral load, there is a 66% reduction in the risk of AIDS and death over time.

In several of the HIV combination treatment studies for early or acute HIV infection (see below), blood plasma HIV levels are driven to undetectable for months and even up to 1-2 years. In those situations, it will become necessary to determine the pres-ence of HIV RNA and DNA in the lymph organs after it has been eradicated from the blood. This is because approximately 98% of lymphocytes reside in lymph organs, compared with only 2% in the blood.

In a late breaker presentation John Todd, MD, of Chiron Corporation in Emeryville,CA, presented a method whereby lymph organs could be tested for HIV RNA viral load levels using branched-chain DNA(bDNA) technology. The authors tested lymph nodes, tonsils and spleen. Only 5-10 mg of tissue is needed. Todd noted that the average viral load in lymph organs ranges from 1 million to 1 billion HIV RNA copies per gram of tissue in untreated HIV positive people. This represents approximately 3 log copies/mL more than is present in the blood plasma.

Brun-Vezinet F and others. HIV viral load changes in Delta patients. Oral presentation and abstract Mo.B.292.

Harris M, Todd J and others. Quantification of HIV-1 RNA in lymphoid tissues: the next step. Late breaker presentation and abstract Th.B.915.

Katzenstein DA and others. Suppression of plasma HIV RNA by reverse transcriptase inhibitors prevents AIDS and death in ACTG 175: combination and monotherapy with ZDV, ddI, and ddC. Oral presentation and abstract Mo.B.293.

Mayers DL and others. Viral burden measurements in CPCRA 007. Late breaker presentation and abstract Th.B.911.

O'Brien WA. Changes in plasma HIV-1 RNA and CD4 lymphocyte counts and the risk of progression to AIDS. New England Journal of Medicine 334:426-431. February 15, 1996.

Phillips AN and others. Effects of nucleoside analog RT inhibitors on plasma HIV RNA and CD4 count as an indicator of clinical effect. Oral presentation and abstract Mo.B.290. Facilitating Diagnosis Of AIDS Dementia Complex

Bruce Brew, MD, from the University of South Wales, reported that worsened states of AIDS dementia complex statistically correlate with increasing levels of HIV RNA viral load in the cerebrospinal fluid (fluid around the brain and spinal cord), and are unrelated to blood plasma HIV viral burden.

Brew, BJ and others. Cerebrospinal fluid (CSF) HIV-1 RNA levels correlate with AIDS dementia complex. Oral presentation and abstract Mo.B.314.

**Early Treatment for HIV Infection

Several oral and poster presentations addressed trials that treat people with HIV shortly after infection, ranging from treatment during the acute (primary) flu-like illness during the months after becoming HIV positive to treatment within the first 1-2 years after infection. Currently, none of these studies is able to demonstrate a slower progression to AIDS or increased survival. However, all of them were able to demonstrate marked decreases in HIV viral load (often to undetectable levels) and, usually, increases in CD4 cell counts. Given the new understanding of the prognostic value of viral load, the beneficial effects on surrogate markers will likely translate into decreased HIV disease progression, increased survival and possibly a prolonged period of years to decades free from HIV disease.

Research has demonstrated that the treatment benefits of combination anti-HIV therapy (decreased HIV progression and increased survival) correlate with treatment-induced reductions in HIV viral load.

Some of the authors of the early treatment trial reports spoke of the possibility of an HIV "cure," or "complete eradication of the virus," if long-term suppression of HIV replication is accomplished. However, measuring the presence or absence of HIV genetic material in immunologically protected sites, including the brain, remains problematic. A healthy, asymptomatic HIV positive person probably would not want to undergo a spinal tap or brain biopsy to determine whether HIV has been eradicated from the brain.

Lange, J. Can HIV be eradicated from an (HIV) infected individual? Late breaker session 436.

**Triple Therapy with Nevirapine, AZT and ddI in Asymptomatic Individuals

* 60% have undetectable HIV viral loads after 1 year * CD4 cell counts increase a mean 120 cells/mm3 after 1 year * Non-compliance with dosing schedule is associated with nevirapine resistance

Impressive results of the BI 1046 (Incas) trial of drug combinations in 151 asymptomatic HIV positive people were presented by Julio Montaner, MD. Participants in the 1 year, randomized, placebo-controlled, international study had baseline CD4 cell counts between 200-600 cells/mm3. All had no prior HIV treatments.

The participants had been HIV positive for a mean of only 1.5 years. Baseline demographics, CD4 cell counts and viral loads were similar in the 3 treatment arms. For the triple therapy group, the mean baseline CD4 cell count and percentage were 367 cells/mm3 and 21%, respectively. The mean baseline HIV RNA viral load was 4.2 log copies/mL.

The 3 treatment arms were: (1) triple therapy with nevirapine (NVP) 200 mg twice daily plus AZT 600 mg daily and ddI 250 or 400 mg daily; (2) AZT plus ddI; and (3) NVP plus AZT.

After 1 year of treatment, the mean reduction in HIV viral load RNA was 1.5 log copies/mL for the triple therapy arm, 1 log for the AZT/ddI arm and a return towards baseline in the NVP/AZT arm. The results were statistically significant. In addition, HIV viral load was below the limit of detection (200 copies/mL using the Roche Amplicor test) in 60% of the triple therapy arm, in 30% of the AZT/ddI arm and in none of the NVP/AZT arm. Moreover, using an ultrasensitive viral load test, two-thirds of the triple therapy arm had an HIV viral load below 20 copies/mL. None in the other 2 arms had HIV RNA levels below 20 copies/mL.

The 1 year CD4 cell count changes were greatest in the triple therapy arm, with a mean increase of 120 CD4 cells/mm3, and counts are still increasing. The AZT/ddI arm sustained a 20 cell/mm3 increase, while the NVP/AZT arm had a CD4 cell count that returned towards baseline.

Interim results of the study also documented that maximum viral load suppression was not achieved in triple therapy enrollees who were not compliant in taking their medication. Moreover, no compliant triple therapy enrollees had NVP-resistant isolates.

Noncompliant triple therapy enrollees had documented NVP-resistant isolates after 6 months.

The most significant side effect of NVP was rash, which occurred in 30% in each of the 2 NVP arms (13% in the AZT/ddI arm). In both of the NVP arms, 8% discontinued therapy due to severe rash.

A similar trial using the same triple therapy in HIV positive people with 6 months or more of prior nucleoside analog therapy was published in the June, 1996 issue of Annals of Internal Medicine. The 398 enrollees from ACTG 241 had more advanced baseline disease, with a mean entry CD4 cell count of 139 cells/mm3. After 48 weeks of triple therapy, the mean HIV viral load was 0.25 log copies/mL lower and the mean CD4 cell count was 18% higher than in the double therapy arm of ddI plus AZT.

The Incas Trial and other studies presented in Vancouver suggest that the non-nucleoside reverse transcriptase inhibitors (NNRTIs), which include NVP, represent the "rising of the Phoenix," due to their significant beneficial anti-HIV effects, which are only evident when the drugs are used in combination therapies. NVP used as monotherapy leads to the rapid development of resistance to HIV.

NVP has distinct advantages over the currently available protease inhibitors (PIs) and the reverse transcriptase inhibitors (RTIs). Unlike the PIs and RTIs, NVP does not require any metabolism by human cells to become active. NVP is already in its active form after absorption. In addition, NVP readily crosses the blood-brain barrier into the brain (achieving even higher penetration levels than AZT), crosses the placenta to the developing fetus and is secreted in breast milk.

NVP was granted FDA approval on June 1, 1996 and became available in August. Other larger trials of NVP and other NNRTIs are ongoing. Other NNRTIs include loviride, delavirdine and atevirdine.

D'Aquila RT and others. Nevirapine, zidovudine, and didanosine compared with zidovudine and didanosine in patients with HIV-1 infection. Annals of Internal Medicine 124:1019-1030. June 15, 1996.

Montaner JG. NNRTIs (non-nucleoside reverse transcriptase inhibitors) in naive patients. Non-nucleoside reverse transcriptase inhibitors, the new class of antiretrovirals. Satellite symposium. Vancouver, B.C. July 9, 1996.

Myers MW, Montaner JG and others. A randomized, double-blinded comparative trial of the effects of zidovudine, didanosine and nevirapine combinations in antiviral-naive, AIDS-free, HIV-infected patients with CD4 counts between 200-600 cells/mm3. Oral presentation and abstract Mo.B.294.

**Triple Therapy for New HIV Infection in 12 Gay Men

* Ritonavir, AZT and 3TC started 65 days after acute HIV infection * After 4 months, HIV viral loads were undetectable * After 4 months, HIV cultures of mononuclear cells were negative * HIV cultures of blood mononuclear cells and plasma continue to show no growth for up to 9 months

Martin Markowitz, MD, from the Aaron Diamond AIDS Research Center in New York City, presented interim data on the treatment of 12 recently HIV-infected gay men with the triple therapy of ritonavir plus AZT plus 3TC (Epivir). All 12 men had had prior symptoms of acute (primary) HIV infection. A precise time of HIV infection that preceded the onset of flu-like symptoms by 15 days (range 6-20) was identified by 9 of the 12 men. Triple therapy was started a mean of 65 days after the onset of flu-like illness. All 12 had detectable HIV RNA at baseline, with a mean viral load of 4.9 log (91,389; range 1,420-953,200) copies/mL. The mean baseline CD4 count was 633 cells/mm3 (range 312-916 cells/mm3). The drug doses were: ritonavir, 600 mg twice daily, AZT, 200 mg 3 times daily, and 3TC, 150 mg twice daily.

Of the 10 patients who completed 3 months of triple therapy, 8 had undetectable HIV viral load (as measured by the Chiron second generation assay, which can detect as few as 500 copies/mL). Of the 3 patients who completed 7 months of therapy, all had undetectable viral load. All 9 patients who completed 4 months of uninterrupted triple therapy had undetectable viral load. Moreover, all 9 patients had undetectable HIV in cultures of blood mononuclear cells and plasma. HIV cultures continue to remain negative for the farthest collection points of the study (7 patients completing 5 months of therapy, 6 completing 6 months of therapy, 3 completing 7 months, 2 completing 8 months, and 1 who completed 9 months of triple therapy). Of the 4 patients who completed 6 months of triple therapy, the mean CD4 cell count was over 850 cells/mm3.

Three patients withdrew from the study, 1 due to intolerance of all 3 drugs and 2 due to non-compliance. Another patient developed an allergy to ritonavir and was switched to indinavir after 7 months. Lymph node biopsies will be performed after 12 months of triple therapy.

The study is ongoing and the researchers anticipate enrolling more patients close to the time of seroconversion to HIV, which is often accompanied by symptoms of acute HIV infection. Further study of the participants may determine whether HIV can be "eradicated" from their bodies, according to Markowitz.

Markowitz emphasized the rationale for very early treatment of HIV infection. He stated that therapy is more likely to be successful if started while the HIV viral population is relatively homogeneous and if the treatment consists of multiple drugs that do not share cross-resistance or overlapping toxicities. He added that early complete suppression of virus will likely prevent drug-resistant virus from emerging.

Markowitz M and others. Triple therapy with AZT, 3TC, and ritonavir in 12 subjects newly infected with HIV-1. Late breaker oral presentation and abstract Th.B.933.

Markowitz M. Treatment intervention in newly infected patients. Emergence of a new approach in HIV disease management. Satellite symposium. Vancouver, B.C.. July 10, 1996.

The Aaron Diamond AIDS Research Center. Norvir, AZT, 3TC regimen renders patients aviremic. News release. July 11, 1996.

**Four- and Five-Drug HIV Therapy for Newly HIV-Infected Men

* Mean HIV viral load reduction of 4.5 log copies/mL observed * No protease inhibitors used

Brad Saget, PhD, Steve Scheibel, MD, and colleagues from San Francisco authored an oral presentation about treating 6 gay men from San Francisco who had been HIV positive for less than 6 months. The treatment consisted of AZT plus ddI (Videx), ddC (Hivid), and interferon-alpha, with the subsequent addition of 3TC. The doses of AZT, ddI and ddC were reduced to 50-66% of the usual doses. The interferon-alpha dose was low, 2 million units self-administered 3 times weekly. Five of the 6 patients never had prior anti-HIV therapy. Baseline HIV viral load ranged from 17,000 to 227,000 copies/mL. Baseline CD4 cell counts ranged from 193 to 1,005 cells/mm3. Baseline HIV viral cultures were all positive.

There was an initial "precipitous drop" in HIV plasma RNA within the first 2 weeks of therapy, followed by a slower decline, resulting in an undetectable HIV viral load in all 6 patients (using the Roche "ultradirect" assay which can measure as few as 10 copies/mL). The maximum decline in HIV viral load was a mean 4.5 log copies/mL, which was sustained over a mean of 30 weeks. The CD4 cell count increased a mean of 121 cells/mm3 over a mean of 29 weeks. After therapy, cultures of blood mononuclear cells for HIV were negative in 5 of 6 patients.

The 1 patient who had had prior anti-HIV therapy sustained a total decline of 5.37 log copies/mL in HIV RNA. Another patient had been treated for over 2 years. A lymph node biopsy after 1.5 years of therapy was negative for HIV RNA and revealed normal lymph node architecture. Therapy was temporarily stopped, and HIV viral load increased again. When combination therapy was reintroduced, viral load returned to undetectable levels again. Ongoing observation of the patients is continuing. It should be noted that these impressive levels of HIV viral load reduction were accomplished without protease inhibitors or non-nucleoside reverse transcriptase inhibitors. The large log decreases in RNA levels achieved in this small study support the canon of several AIDS researchers, "treat early and treat hard." It also supports the concept that early in HIV infection, whole body HIV viral load (including all lymph organs) has not yet reached its peak. It may take many months or longer for the full comple-ment of HIV viral replication to reach a maximum in terms of HIV DNA and RNA. In addition, there have been fewer cycles of HIV replication to establish mutant or resistant viral strains.

Saget B and others. Dramatic suppression of HIV-1 plasma RNA using a combination of zidovudine, didanosine, zalcitabine, lamivudine, and interferon- alpha in subjects with recent HIV-1 infection. Oral presentation and abstract We.B.533.

Scheibel S and others. Extreme suppression of HIV-1 plasma RNA using a combination of zidovudine, didanosine, zalcitabine, lamivudine, saquinavir, and interferon-alpha in subjects with HIV-1 infection. Poster presentation and abstract We.B.3128.

**Combination Treatment During Acute HIV Infection

* Viral loads driven to undetectable in the majority of subjects * Protease inhibitors not always needed * Symptoms of acute infection resolve with treatment * One patient sustained a 6 log decrease in HIV viral load

Several presentations addressed the experimental treatment of primary HIV infection (PHI). Luc Perrin, MD, from University Hospital in Geneva, Switzerland, reported on using 2-5 different anti-HIV therapies for the very early manifestations of HIV infection. Most patients were treated with low dose AZT (250 mg every 12 hours) plus ddI (200 mg twice daily). Some were treated with the triple combination of AZT plus ddI plus 3TC, while others were treated with AZT plus 3TC plus indinavir. A total of 18 treated PHI patients were compared with untreated PHI patients and with AZT monotherapy-treated historical controls.

For the AZT/ddI combination therapy group, the mean baseline HIV RNA viral load was 5.1 log copies/mL, which decreased to a mean of 1.7 log copies/mL after 6 months and 1.3 log copies/mL after 1 year. Approximately 75% of the enrollees had undetectable HIV viral loads after 2-3 months that persisted for 1 year (using the Roche Amplicor research test, which can measure as few as 20 copies/mL. Undetectable viral loads were found in only 3% of the untreated or AZT monotherapy control groups. The CD4/CD8 ratio tended towards normal in the combination therapy arm.

Perrin noted that the glycoprotein (gp) 41 band on one patient's Western blot confirmatory antibody test began to diminish after combination therapy. He commented on another patient who discontinued therapy after 6 months, and whose viral load increased to baseline 2 weeks later. Twelve patients have continued combination therapy for 10 months.

Perrin stated that aggressive treatment during PHI is extremely important to limit HIV spread into the lymph nodes before it establishes itself. Perrin further believes that an aggressive therapy approach with 3 (or more) anti-HIV drugs for an unspecified time period starting with PHI might be able to be followed by a "maintenance" treatment period, in which fewer drugs could be used.

A second report about treating primary HIV infection was described by Brian Conway, MD, from the British Columbia Center for Excellence in HIV/AIDS. A vigorous campaign targeting emergency rooms and clinics for gay/bisexual men and injection drug users found 18 persons experiencing PHI. The researchers screened referrals with the HIV p24 antigen and enzyme-linked immunosorbent assay (ELISA) antibody tests. The 18 had positive antigen tests, usually with a negative antibody test.

Seven of 8 gay/bisexual men and 1 of 10 injection drug users consented to enroll in the pilot, open-label trial of combination therapy for PHI. Four were treated with AZT plus ddI, while 3 others were treated with AZT plus 3TC. The eighth subject remained on AZT monotherapy due to intolerance of other antiretroviral therapies. The mean CD4 cell count at baseline was 510 cells/mm3. The median baseline HIV RNA viral load was 139,305 copies/mL.

All participants demonstrated a marked reduction in viral load, with a mean decline of 3.7 log copies/mL for combination therapy patients. Half achieved an undetectable viral load after 8 weeks of treatment (using the Roche Amplicor test, which can measure as few as 500 copies/mL). At baseline, most patients had fatigue and loss of appetite. One had oral thrush (candidiasis), while another had cytomegalovirus (CMV) infection of the rectum. All patients experienced resolution of all PHI symptoms within 1-2 weeks after starting therapy. Conway and colleagues are continuing their study.

A late breaker poster described the resolution of severe PHI symptoms in a man after only 5 days of combination therapy. The lead author was Cassy Workman, MD, from Australia. The subject was a 35-year-old man who presented to Workman with a 4 day history of severe PHI symptoms. Combination therapy was started 26 days after his behavioral exposure to HIV. Therapy included AZT 500 mg daily, 3TC 600 mg daily, and saquinavir 7,200 mg daily. d4T (Zerit) 80 mg daily was added 53 days after the triple combination was started.

HIV RNA viral load decreased from over 3 million copies/mL at baseline to 2,000 copies/mL at week 4, to 400 copies/mL at week 7 and to undetectable from weeks 10-17. This represents a 6 log decrease in HIV viral load, the largest ever reported. The baseline CD4 count of 574 cells/mm3 increased by 220 cells/mm3 after therapy. Similar to the report by Perrin (above), Workman also reported that the antibody bands on the Western blot antibody test were very atypical, with many having decreased intensity or never developing. The patient in this report tolerated the therapy extremely well, according to Workman.

This series of reports describing treatments for PHI and early HIV infection represent major ground-breaking efforts in HIV/AIDS clinical care. Even though the numbers of patients in the studies are small, the emerging pattern is clear. Since treatment-induced reductions of viral load in other studies have translated into slower HIV progression and increased survival, it is likely that early treatments for HIV will accomplish the same thing. Therefore, it is extremely likely that early treatments for HIV will one day become the standard of care. This is particularly the case for primary HIV illness, when the virus has not yet seeded the entire lymph system. Otherwise, during early HIV infection (after PHI), an elevated viral load represents a clear indication for early intervention with combination therapy. (See BETA, June 1996, pages 10, 39-41 for new SFGH/SFDPH Guidelines).

New public information campaigns in all urban areas should be undertaken to find people in the midst of seroconversion illness and give them combination HIV therapy. (These seroconverters should be followed in observational studies so that the best drug combinations can be determined and long term outcomes can be documented. The pharmaceutical industry should provide financing for the drugs used until FDA approves the drugs for PHI.) A few years or more of combination therapy after PHI will decrease the transmission of HIV, slow the epidemic, decrease HIV progression, save lives and save money in the long run by avoiding the high cost of AIDS care and drugs for opportunistic infections, cancers and wasting.

Azar R, Conway B and others. Combination antiretroviral therapy for the treatment of acute HIV infection. Oral presentation and abstract We.B.531.

BETA 10, 39-41. June 1996.

Holodniy M and others. A pilot study to evaluate the efficacy of zidovudine versus placebo in primary HIV infection (Datri 002): a preliminary analysis. Late breaker poster and abstract LB.B.6022.

Perrin L and others. Reduced viremia and increased CD4/CD8 ratio in patients with primary HIV infection treated with AZT-ddI. Oral presentation and abstract We.B.532.

Workman, C and others. Rapid viral load decrease in primary infection associated with aggressive therapy. Late breaker poster and abstract LB.B.6021.

**Triple Therapy with Nevirapine, AZT and ddI in Infants

* 2 infants become negative for HIV in viral load assays, cultures and ELISA antibody tests

A most interesting report on the beneficial effects of triple therapy with nevirapine plus AZT plus ddI was presented by John Sullivan, MD, from the University of Massachusetts. A subset analysis of HIV positive infants from ACTG 180 was presented. Eight HIV-infected infants aged 2-16 months were treated with the triple therapy. Two of those infants were twins who started the triple therapy at age 2 months. Their baseline HIV RNA viral loads were 295,000 and 331,036 copies/mL, respectively.

After 22 weeks of triple therapy, both of their viral loads were undetectable (less than 200 copies/mL). Testing of the twins after 11 months of triple therapy revealed that both infants had negative HIV cultures from their blood plasma and blood mononuclear cells. Their ELISA HIV antibody blood tests became negative and their confirmatory Western blot antibody tests became indeterminate (loss of several antibody bands). In addition, the twins blood immunoglobulin type G (IgG) levels normalized (most infants with HIV have abnormally high IgG levels). Lastly, the twins had normal antibody responses to standard infant vaccinations. However, a sensitive research PCR test for HIV genetic material remained positive. The infants were healthy and thriving, without any signs or symptoms of HIV disease.

Sullivan believes that the impressive results indicate that here was not enough HIV genetic material present in the twins to stimulate an antigenic response by their immune systems to make enough HIV antibodies, leading to the lack of measured HIV antibodies on the ELISA tests. In addition, the results represent evidence of a sustained reduction of HIV viral replication. Sullivan indicated that only time will tell whether the twins will be "cured" of their HIV infection.

Sullivan J. NNRTI (non-nucleoside reverse transcriptase inhibitor) pediatric experience. Non-nucleoside reverse transcriptase inhibitors, the new class of antiretrovirals. Satellite symposium. Vancouver, B.C. July 9, 1996.

**Can HIV be Eradicated from HIV Positive Persons?

* One and a half to 3 years of complete HIV inhibition necessary to eradicate HIV from latently infected cells, excluding sanctuary sites * HIV drugs in liposomes may help target lymph organs

David Ho, MD, from the Aaron Diamond AIDS Research Center in New York, summed up current dogma regarding HIV and disease:

* No HIV - No AIDS * Attenuated (weakened) HIV - No progression * Constant HIV replication - Constant CD4 cell destruction * Increased HIV replication - Fast progression * Decreased HIV replication - Slow progression * No HIV replication - No progression

Ho also commented that therapies to treat HIV during acute or primary HIV infection may be different from those used during later stage HIV disease. The latter group of patients may also need immune modulation therapy in addition to combination anti-HIV therapies. During PHI, perhaps only antiretroviral therapies are needed, as already suggested by the above studies. This is probably the case, because during PHI the immune system is still intact.

In a separate presentation, Ho addressed the issue of how long combination anti-HIV therapy would need to be given before HIV "eradication" would be possible. Ho and his colleagues used mathematical models to make predictions. One assumption is that combination HIV therapy would need to drive HIV viral replication to zero, i.e., zero viral load, and keep it there for an extended time period.

Ho remarked that combination therapy leads to a fast decline in viral load (days to weeks), followed by a slower decline (weeks to months). He believes that the first decline represents the loss of activated lymphocytes that produce HIV particles. Those lymphocytes have a mean half-life of 1.25 days. The second, slower decline probably represents persistent viral production from long-lived cells, i.e., macrophages, infected before HIV therapy was started. He calculated that these long-lived cells have a mean half-life of 13.3 days.

Using the estimates that a person has approximately 1 trillion (1012) lymphocytes and 100-300 billion (1011) macrophages, Ho estimated that 30-120 weeks is the minimum time needed to eradicate HIV from those 2 groups of cells. Therefore, he hypothesizes that completely inhibitory treatment using combination therapy would need to be given for approximately 1.5 to 3 years. He adds that the calculations do not consider a possible, even slower, third phase of viral decay, or the "possibility of a sanctuary site," such as the brain.

Ho's hypothesis also assumes that all latently infected cells eventually divide, reproduce or die. The current combination therapies merely block HIV infection of new cells and do not "seek out" or target all HIV-infected cells. Central nervous system cells are not known to divide or reproduce.

The prospect of eradicating HIV from infected persons clearly involves targeting the virus in many different organs, particularly the lymph organs (lymph nodes and spleen), as well as immunologically protected sites like the brain. Harvie Pierrot, from Universite Laval in Quebec, presented a paper entitled, "Targeting Lymphoid Organs in HIV Disease." He stated that incorporating antiretroviral drugs in liposomes (fat globules) improves drug accumulation in lymph nodes and spleen, associated with a longer drug half-life. This also allows for less frequent dosing of drugs. Liposomal drugs have already been approved by FDA for AIDS-related Kaposi s sarcoma (see BETA, June 1996, pages 7 and 11).

In a related late breaker presentation, John Todd, from Chiron Corporation in Emeryville, CA, presented a method whereby lymph organs could be tested for their HIV RNA viral load levels using bDNA technology. The authors tested lymph nodes, tonsils and spleen. Only 5-10 mg of tissue is needed. They noted that the average viral load in lymph organs ranges from 1 million to 1 billion HIV RNA copies per gram of tissue in untreated HIV positive people. This represents approximately 3 log copies/mL more than in the blood plasma.

BETA, pages 7 and 11, June 1996.

Harris M, Todd J and others. Quantification of HIV-1 RNA in lymphoid tissues: the next step. Late breaker presentation and abstract Th.B.915.

Ho DD. Pathogenesis: resolved that viral factors, and not host factors, are the primary determinants of pathogenesis, affirmative. Plenary session 400.

Perelson AS, Ho DD and others. How long should treatment be given if we had an antiretroviral regimen that completely blocks HIV replication? Late breaker presentation and abstract Th.B.930.

Pierrot H and others. Targeting lymphoid organs in HIV disease. Oral presentation and abstract Th.A.155.

Protease Inhibitors with or without Reverse Transcriptase Inhibitors

**Saquinavir plus Ritonavir Combination Shows Synergy

In patients with past therapy with reverse transcriptase inhibitors:

* 6 week viral load reduction of 2.4 log copies/mL * 6 week viral load undetectable in 86% * 6 week CD4 cell count increase of 98 cells/mm3 and increasing

D. William Cameron, MD, from the University of Ottawa, presented interim results of an open-label, multicenter, dose-ranging study in the U.S. and Canada using the protease inhibitors saquinavir and ritonavir. A total of 120 HIV positive patients with CD4 cell counts ranging between 100-500 cells/mm3 received 1 of 4 regimens combining saquinavir plus ritonavir. Data were presented for 43 patients who received 6 weeks of therapy with either saquinavir 400 mg twice daily plus ritonavir 400 mg twice daily, or saquinavir 400 mg twice daily plus ritonavir 600 mg twice daily. The mean baseline HIV RNA viral load was 4.6 log copies/mL, while the mean baseline CD4 cell count was 268 cells/mm3. All enrollees were required to discontinue their reverse transcriptase inhibitor therapy before starting the study. None of the patients had prior therapy with PIs.

After 6 weeks of therapy, the median reduction of HIV viral load was 2.4 log copies/mL of RNA, with a median increase of 98 CD4 cells/mm3. Moreover, 86% of participants had an HIV viral load below detection (200 copies/mL). These changes are greater than would be expected from either drug alone (synergy). Only 3% of patients discontinued treatment due to adverse effects, mostly gastrointestinal. The study will continue for a total of 1 year.

The 2 other doses in the study are saquinavir 600 mg twice daily plus ritonavir 600 mg twice daily, and saquinavir 400 mg 3 times daily plus ritonavir 400 mg 3 times daily. Results from these latter 2 dosing groups were not presented. Saquinavir and ritonavir are the 2 protease inhibitors that have independently demonstrated decreased HIV disease progression and increased survival. Their resistance patterns are somewhat different. Combining the 2 appears to allow for twice daily dosing with saquinavir. Observation is continuing.

Cameron DW and others. Combination use of ritonavir and saquinavir in HIV-infected patients: preliminary safety and activity data. Oral presentation and abstract Th.B.934.

Cameron DW. Synergistic action between ritonavir and saquinavir: implications for treatment. Emergence of a new approach in HIV disease management. Satellite symposium. Vancouver, B.C. July 10, 1996.

**Triple Therapy: Indinavir, AZT and 3TC

After 11 months (48 weeks) in AZT-experienced subjects:

* HIV viral load reduced by 2.3 log copies/mL (7 patients) * 86% have undetectable viral loads in blood (7 patients) * CD4 cell counts increase by a median of 218 cells/mm3 (at 44 wks) * HIV resistance occurs least often with triple therapy

Condra JH and others. Bi-directional inhibition of HIV-1 drug resistance selection by combination therapy with indinavir and reverse transcriptase inhibitors. Oral presentation and abstract Th.B.932.

Emini EA and others. Maintenance of long-term virus suppression in patients treated with the protease inhibitor Crixivan (indinavir). Oral presentation and abstract Mo.B.170.

Gulick R and others. Potent and sustained antiretroviral activity of indinavir, zidovudine and lamivudine. Oral presentation and abstract Th.B.931.

Merck and Company, Inc. Late breaker abstracts for protease inhibitor Crixivan. News information. July 1996.

**Indinavir Monotherapy: Continued Benefits at 48 Weeks

* 54% have undetectable HIV RNA viral loads (63 patients) * Viral load reductions greater than 2.3 log copies/mL * CD4 counts increase over 80 cells/mm3 * Daily doses greater than 2.4 grams provide no added benefits

Steigbigel R and others. Extended follow-up of patients in a study of indinavir at 800 mg every 8 hours (2.4 grams per day), 1000 mg every 8 hours (3 grams per day) and 800 mg every 6 hours (3.2 grams per day). Oral presentation and abstract Mo.B.412.

**Triple Therapy: Ritonavir, AZT and ddC

After 14 months in 17 subjects without prior HIV treatment:

* HIV viral load reduced by 1.9 log copies/mL * 59% have undetectable HIV viral loads in blood * 60% have negative HIV blood cultures * CD4 cell counts increase by a mean of 180 cells/mm3

Katlama C. Triple therapy with ritonavir, ddC, and AZT: study update. Emergence of a new approach in HIV disease management. Satellite symposium. Vancouver, B.C. July 10, 1996.

Mathez D and others. A triple combination of ritonavir plus AZT plus ddC as a first line treatment of patients with AIDS: update. Oral presentation and abstract Mo.B.175.

Abbott Laboratories. Triple therapy benefits with Norvir sustained at 60 weeks. News release. July 8, 1996.

**Ritonavir Plus Other Anti-HIV Treatments Increases Survival

* After 1 year, 33% reduction in deaths * After 1 year, 55% decreased HIV disease progression or death * Increased quality of life

BETA, page 44, June 1996 and pages 7-8, March 1996.

Cameron W and others. Prolongation of life and prevention of AIDS complications in advanced HIV immunodeficiency with ritonavir: update. Oral presentation and abstract Mo.B.411.

Danner S. Ritonavir Phase III studies: overview. Emergence of a new approach in HIV disease management. Satellite symposium. Vancouver, B.C. July 10, 1996.

Heath-Chiozzi M and others. Ritonavir clinical benefit correlates with HIV RNA and CD4 cell levels in advanced HIV illness. Poster presentation and abstract We.B.3127.

Nabulsi A and others. The use of Euroqol preference scale in AIDS; results from two clinical trials. Late breaker poster and abstract LB. B.6046.

Nabulsi A and others. Quality of life consequences of adding Ritonavir to current

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Copyright © 1996 - San Francisco AIDS Foundation. Reproduced by permission. Reproduction of this article (other than one copy for personal reference) must be cleared through BETA: PO Box 426182, San Francisco, CA 94142-6182. Tel: 415 487 8060 Fax: 415 487 8069 URL: http://www.sfaf.org/beta E-mail: beta@sfaf.org

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