Efavirenz, nelfinavir, and stavudine rescue combination therapy in HIV-1-positive patients heavily pretreated with nucleoside analogues and protease inhibitors

Tolerability, activity, and pharmacokinetic parameters of a combination therapy with efavirenz (EFV), nelfinavir (NFV), and stavudine (d4T) were evaluated in this study. Forty-seven HIV-1-infected study subjects, naive to NFV and nonnucleoside reverse transcriptase inhibitors (NNRTIs), who had experienced virologic failure while being treated with combination antiretroviral therapies including protease inhibitors (PIs), were enrolled. At baseline, HIV-1 viral load in plasma was 4.8 log10, CD4+ count was 204 cells/microl (both mean values); patients had received a mean of 3.1 different treatments (range, 2-5 treatments). Study medications were generally well tolerated; 7 of 47 patients (14.8%) were dropped from the study because of related drug toxicity. At week 24, mean plasma viral load (pVL) was reduced by 1.9 log10, with mean CD4+ count increased to 324 cells/microl (+/-59% from baseline); pVL was below the limit of detection (500 copies/ml) in 46.1% of patients. An extended follow-up study was performed at 12 months. Results showed a reduction of 1.7 log10 in pVL from basal values that was consistent with values observed at months 3 and 6. A history of previous use of PIs represented a negative prognostic marker. Sequencing analysis, performed in a subset of patients, showed the presence of multiple point mutations associated with PI resistance. Pharmacokinetic analysis demonstrated a marked interindividual variability in NFV plasma concentrations, producing in 4 of 18 patients (22%) trough concentrations lower than minimum effective concentration. In pretreated patients, further studies are needed to characterize the pharmacokinetic factors that affect response to therapy and the association of these results with the 95% inhibitory concentration (IC95) determined by phenotyping.

Incidence and predictors of virologic failure of antiretroviral triple-drug therapy in a community-based cohort

Highly active antiretroviral therapy fails to reach its recommended goal of sustained suppression of viral replication in a substantial proportion of patients. We analyzed incidence and predictors of virologic failure of the first regimen of a triple-drug combination therapy, including a protease inhibitor and two nucleoside analog reverse transcriptase inhibitors (NRTIs), in 274 HIV-infected patients. Long-term virologic response to combination therapy including salvage regimens was assessed 2.5 years after treatment initiation. During an initial observation period of up to 1.8 years (median, 0.8 years) 152 patients (55%) experienced sustained suppression of HIV-1 RNA to <500 copies/ml. Failure to reduce viral load to <500 copies/ml within 6 months (initial failure) was observed in 51 patients (19%). Independent risk factors for initial failure included higher baseline viral load; addition of a protease inhibitor to an unchanged NRTI regimen; use of saquinavir hard-gel capsules; and longer duration of prior NRTI treatment. Within a median of 7 months viral load rebound above 500 copies/ml occurred in 71 of 223 patients (32%) whose viral load had initially decreased below this threshold. In proportional hazard analysis none of the potential risk factors was significantly associated with viral load rebound. However, in 40 patients (56%) with viral load rebound, incomplete adherence to therapy or treatment interruptions preceded the rebound. Virologic outcome after 2.5 years correlated with initial response to the first regimen: viral load was <500 copies/ml in 88, 55, and 21% of patients with sustained suppression, viral load rebound, and initial failure, respectively.

A randomized study comparing triple versus double antiretroviral therapy or no treatment in HIV-1-infected patients in very early stage disease: the Spanish Earth-1 study

BACKGROUND

Most current guidelines state that antiretroviral therapy should be considered for HIV-infected patients with plasma HIV RNA > 5000-10000 copies/ml and CD4 cells > 500 x 10(6) cells/l. However, there is increasing concern about whether this is the optimal point to begin treatment or whether it is better to delay the initiation to more advanced stages.

OBJECTIVE

To study the immunological and virological benefits of starting antiretroviral therapy at these early stages.

METHODS

A total of 161 HIV-infected asymptomatic patients with CD4 cell count > 500 x 10(6) cells/l and viral load > 10000 copies/ml were randomly assigned to one of five treatment groups: no treatment, twice daily zidovudine and thrice daily zalcitabine (ZDV-ddC), twice daily zidovudine and didanosine (ZDV-ddI), twice daily stavudine and didanosine (D4T-ddI), or a twice daily three-drug regimen with stavudine and lamivudine and ritonavir. The endpoints were progression to < 350 x 10(6) cells/l CD4 cells, to < 500 x 10(6) cells/l with either two Centers for Disease Control class B symptoms or an increase of viral load > 0.5 log10 copies/ml above baseline, or to AIDS or death. In various substudies, the lymphoid tissue and cerebrospinal fluid viral load, development of genotypic resistance, proliferative responses to mitogens and cytomegalovirus, and HIV-1 specific antigens and other immunophenotypic markers were also analysed.

RESULTS

Progression rates to study endpoints within 1 year were greater in the control group (31%) than in all groups receiving antiretroviral therapy pooled together (5%; estimated hazard ratio 7.41; 95% confidence interval 5.72-74.55; P < 0.001). The peak mean viral load decrease was greater in the three-drug group when compared with any of the three groups with a two-drug regimen (2.32, 1.65, 1.72 and 1.84, respectively; P < or = 0.001). At 1 year, viral load remained below 20 copies/ml in 30 out of 33 patients in the three-drug group (91%) and in only eight out of 94 patients (9%) in two-drug groups (P = 0.001). The peak mean increase in CD4 cells was also greater in the three-drug group than in the double treatment arms (259 versus 85, 144 and 145 x 10(6) cells/l, respectively; P = 0.001). By comparison, 36% of patients in the three-drug group regimen had to change the therapy as a result of adverse events. Substudies were performed in 60 patients recruited at two sites. Tonsillar tissue HIV RNA was measured in seven patients (two in the two-drug groups and five in the three-drug group) in whom plasma HIV RNA was < 20 copies/ml at 1 year. It was 15151 and 133333 copies/mg tissue in the two patients from the two-drug group, < 40 copies/mg tissue in four patients in the three-drug group, and 485 copies/mg in one patient in the three-drug group. At 1 year there was a mean increase of 4.21+/-2.94% in CD8+CD38+ cells in the control group and a decrease of 9.48+/-3.36% in the two-drug groups (P = 0.01), and 19.87+/-3.64 in the three-drug group (P = 0.001 and P = 0.05, for comparisons with control group and two-drug groups, respectively). Although proliferative responses to cytomegalovirus antigens were significantly greater in those receiving antiretroviral therapy, response to HIV-1 p24 antigen was not detected in any patient in either treatment group.

CONCLUSIONS

This study supports the recommendation to start antiretroviral therapy with a three-drug combination during very early stages of HIV-1 disease, at least if viral load is above a cut-off point (10000 copies/ml in our study). The risk of progression was sevenfold higher in non-treated patients at 8 months of follow-up. Some immune system parameters improved toward normal values after 1 year of antiretroviral therapy, but the proliferative response of CD4 T lymphocytes against the p24 HIV-1 antigen was not recovered. Therapeutic approaches with more potent, better-tolerated and more convenient regimens will increasingly favour early intervention with antiretroviral t

Resolution of HIV-associated nephrotic syndrome with highly active antiretroviral therapy delivered by gastrostomy tube

There is no consensus regarding the specific management of HIV-associated nephrotic syndrome. We report a child whose first manifestation of human immunodeficiency virus type 1 (HIV-1) infection was nephropathy and wasting syndrome associated with profound immunodeficiency. The patient had a dramatic clinical and immunologic response to triple antiretroviral therapy delivered through a gastrostomy tube, with complete resolution of nephrotic syndrome. A 51/2-year-old African-American girl presented with a 2-week history of cough, chest pain, vomiting, loose stools, abdominal distention, anorexia, and fever. In addition, she had recurrent oral thrush. Her weight and height were below the 5th percentile. She was chronically ill, appearing with oropharyngeal thrush and pitting edema in lower extremities. She had scattered rhonchi and decreased breath sounds on both lung bases. Her abdomen was distended and diffusely tender. A chest radiograph showed consolidation of the right upper and left lower lobes with bilateral pleural effusion. Admission laboratories were consistent with nephrotic syndrome. Streptococcus pneumoniae grew from the blood culture and the child responded well to treatment with intravenous ceftriaxone. She was found to be HIV-infected, her CD4(+) cell count was 3 cells/mcL and her plasma HIV-1 RNA was >750 000 copies/mL. A percutaneous gastrostomy tube was placed for supplemental nutrition. She was treated with stavudine, lamivudine, and nelfinavir via gastrostomy tube with good clinical response. Twenty-one months after instituting antiretroviral therapy, her weight and height had increased to the 50th and 10th percentile respectively, and she had complete resolution of her nephrotic syndrome. Her CD4(+) cell count increased to 1116 cells/mcL and her viral load has remained undetectable. HIV-1 associated nephrotic syndrome has been described in children with profound immunodeficiency. The course of untreated HIV-associated nephrotic syndrome is rapid progression to renal failure in up to 40% of the children. Regardless of the presence of renal insufficiency, if untreated, it is uniformly fatal. A modest improvement of HIV-1 associated nephrotic syndrome has been observed in patients treated with zidovudine. Steroid and cyclosporine treatment have resulted in improved renal function but long-term use of immunosuppressive therapy has raised concerns about safety. We have described, to our knowledge, the first child with HIV-associated nephrotic syndrome who had a remarkable clinical, immunologic, and virologic response to triple-drug combination therapy given by gastrostomy tube, with complete resolution of proteinuria and normalization of the serum albumin. She also had a striking improvement in weight, height, and quality-of-life. Whether the presence of a gastrostomy tube contributed to the excellent response because of improved compliance is unknown, but warrants systematic evaluation.

[Fatal lactic acidosis in a patient with acquired immunodeficiency syndrome treated with stavudine, lamivudine and indinavir]

Recently, several class-related adverse events have been recognized with antiretroviral drugs. For nucleoside analogue reverse transcriptase inhibitors. (NRTI), lactic acidosis with hepatomegaly and hepatic steatosis have been reported. These appear to occur at a low frequency, but with a high fatality rate. We report a case of fatal lactic acidosis in a patient with acquired immunodeficiency syndrome (AIDS) treated with stavudine (d4T), lamivudine (3TC) and indinavir (IDV). A 48-year-old male AIDS patient was admitted with complaints of general fatigue and dyspnea. His medications at presentation included d4T, 3TC and IDV. Physical examination demonstrated icteric sclerae and abdominal tenderness with hepatomegaly. Laboratory data demonstrated a severe metabolic acidosis with an anion gap due to lactate accumulation. Despite intensive treatment, cardiorespiratory arrest occurred and this could not be resuscitated.

Emergence of zidovudine and multidrug-resistance mutations in the HIV-1 reverse transcriptase gene in therapy-naive patients receiving stavudine plus didanosine combination therapy. STADI Group

OBJECTIVE

Assessment of genotypic changes in the reverse transcriptase gene of HIV-1 occurring in antiretroviral naive patients treated by stavudine plus didanosine combination therapy.

METHODS

Sequence analysis (codons 1-230) was performed after amplification of the reverse transcriptase gene from plasma samples collected at baseline and at the end of treatment from 39 previously treatment-naive patients treated for 24-48 weeks.

RESULTS

At baseline, mutations associated with zidovudine resistance were detected in plasma from two patients: Asp67Asn/Lys219Gln and Leu210Trp. Among the 39 subjects, 18 (46%) developed mutations: one developed the Val75Thr/Ala mutation, four (10%) developed a Gln151Met multidrug-resistance mutation (MDR), associated in one of them with the Phe77Leu and the Phe116Tyr MDR mutations and 14 (36%) developed one or more zidovudine-specific mutations (Met41Leu, Asp67Asn, Lys70Arg, Leu210Trp, Thr215Tyr/Phe). The development of a Met41Leu zidovudine-specific mutation was associated with the development of a Gln151Met mutation in one patient. Other reverse transcriptase mutations known to confer resistance to nucleoside analogues were not detected. At inclusion, there was no statistical difference in HIV-1 load between patients who developed resistance mutations and those who did not. RNA HIV-1 load decrease was higher (P = 0.05) in patients who maintained a wild-type reverse transcriptase genotype (-2.22 log10 copies/ml) than in patients who developed resistance mutations (-1.14 log10 copies/ml).

CONCLUSION

Stavudine/didanosine combination therapy is associated with emergence of zidovudine-related resistance or MDR mutations in naive patients. These findings should be considered when optimizing salvage therapy for patients who have received a treatment including stavudine/didanosine combination.

Preliminary experiences with triple therapy including nelfinavir and two reverse transcriptase inhibitors in previously untreated HIV-infected children

OBJECTIVE

In an intent-to-treat study increase in CD4 cell count, reduction of viral load, clinical benefit and adverse reactions were examined in HIV-infected previously treatment-naive children taking triple therapy.

METHODS

sixteen HIV-infected children in category A or B on antiretroviral triple therapy were followed-up for a period of 12 months. In group I eight patients received zidovudine, lamivudine and nelfinavir; in group II eight patients received stavudine, didanosine and nelfinavir. Viral load and CD4 cell count were measured every 4-8 weeks. Plasma nelfinavir levels were assessed once in all patients at baseline and monitored in patients with increasing viral load.

RESULTS

No significant differences were observed between treatment groups in terms of CD4 cell counts and viral load. A median viral load reduction of 2.8 log10 (range, 1.4-4.2 log10) was achieved over a period of 12 months in both groups. Viral load < 500 copies/ml was found in 69% of patients and viral load < 50 copies/ml in 44% of patients after 12 months. Median CD4 cell count increased from 656 x 10(6) to 850 x 10(6) cells/l after 3 months and was maintained at 813 x 10(6) cells/l after 12 months of treatment. Main side-effects were diarrhoea, rash and hyperlipidaemia. Except for application problems, both regimens were well tolerated. Appropriate formula and individual counselling must be performed during the first weeks of treatment in order to achieve good compliance in paediatric patients.

CONCLUSION

Triple antiretroviral therapy shows a stronger and more sustained reduction of viral load in HIV-infected children compared with studies combining two nucleoside analogues.

Stavudine, lamivudine and indinavir in drug abusing and non-drug abusing HIV-infected patients: adherence, side effects and efficacy

OBJECTIVES

To compare adherence and clinical outcome with highly active antiretroviral therapy (HAART) in intravenous drug users (IDUs) and subjects with other HIV risk behaviours (non-IDUs).

METHODS

A total of 133 non-naive HIV-infected patients, 95 (71%) IDUs and 38 (29%) non-IDUs received triple drug therapy with stavudine, lamivudine, and indinavir. Adherence, side effects, and immunological and virological efficacy of treatment were assessed every 3 months.

RESULTS

During a median follow-up of 12 months, 43 patients (32% of the total) showed adequate adherence in all clinical appointments. Adherence was superior in non-IDUs than in IDUs in every visit, but a significant difference was found only at 6 months, when 22 (58%) non-IDUs versus 37 (39%) IDUs were adherent (P = 0.047). Mildly increased bilirubin was observed in 69 (52%) patients, and renal colic in 34 (26%). No difference in side effects was found between IDUs and non-IDUs. After 6 months of treatment, 35 (43%) participants presented a CD4 cell count increase >100x10(6)/l, and 47 (58%) achieved undetectable HIV RNA (lower limit of detection: 200 copies/ml). CD4 cell count and HIV RNA responses were similar in both groups.

CONCLUSIONS

Adherence to the employed HAART regimen was poor. Non-IDUs were more adherent than IDUs, but the difference between both groups was small. Side effects and efficacy were similar in IDUs and non-IDUs.

Virological and immunological responses to once-daily dosing of didanosine in combination with stavudine. AI454-143 Team

OBJECTIVE

To compare the antiviral activity of once-daily didanosine (ddI) and twice-daily ddI in combination with stavudine (d4T).

DESIGN

Randomized, double-blind, multicenter study.

SETTING

Twenty-one sites in the United States.

PATIENTS

Eighty-seven antiretroviral-naive, HIV-1-infected adults with baseline plasma HIV RNA counts of > or = 10,000 copies/ml and CD4 cell counts of > or = 100 cells/mm3 started study therapy.

INTERVENTIONS

Patients received once-daily ddI or twice-daily ddI, each combined with twice-daily d4T.

MAIN OUTCOME MEASURES

Plasma HIV-1 RNA levels, CD4 cell counts, and adverse events were regularly monitored. The primary efficacy analysis used was the time-averaged difference (TAD) between treatment regimens in change from baseline plasma HIV-1 RNA levels over the first 12 weeks of therapy.

RESULTS

At week 12, median log10 HIV-1 RNA changes were -1.83 log10 copies/ml in the once-daily ddI/d4T group and -1.80 log10 copies/ml in the twice-daily ddI/d4T group, and 18 out of 44 patients (41%) and 17 out of 43 patients (40%), respectively, had HIV-1 RNA levels below 400 copies/ml. Similar results were seen at week 24. The TAD between the two treatment groups (once-daily ddI/d4T minus twice-daily ddI/d4T) in change from baseline plasma HIV RNA levels over the first 12 weeks was 0.14 log10 copies/ml (95% CI: -0.11, 0.40). At week 12, subjects averaged an increase in CD4 cell count of over 140 cells/mm3. The TAD between the two treatment groups in change from baseline CD4 cell counts over the first 12 weeks was 2 cells/mm3 (95% CI: -40, 45).

CONCLUSION

Once-daily ddI plus d4T and twice-daily ddI plus d4T were similarly effective in reducing plasma HIV-1 RNA levels and increasing CD4 cell counts over 12-24 weeks of therapy.

Failure of double protease inhibitor therapy as a salvage therapy for HIV-infected patients resistant to conventional triple therapy

A therapeutic dilemma arises once HIV-infected patients develop a break-through of HIV-replication under potent antiretroviral therapy. Therefore, we studied whether patients (n = 12) who failed double nucleoside reverse transcriptase (NRTI) plus indinavir or ritonavir triple therapy can be rescued when therapy is switched to double protease inhibitor (PI) treatment (nelfinavir and hard gel saquinavir) and stavudine. With the rescue regimen HIV-RNA levels initially dropped from 148,571 +/- 45,258 copies/ml to 9,310 +/- 6, 965 copies/ml at week 4 (p = 0.0117). However, virus load subsequently increased to almost baseline levels (131,230 +/- 37,743 copies/ml) at week 12. Likewise, CD4-cell counts could only be stabilized initially (baseline 267 +/- 51; week 4 296 +/- 65 cells/microl), but gradually declined thereafter (216 +/- 34 cells/microl week 12). Before therapy was switched, the viral protease gene from 5 analyzed patients showed 3-5 amino acid substitutions. Moreover, 4 of these patients had one amino acid substitution associated with resistance to nelfinavir. Our data suggest that HIV-infected patients resistant to indinavir or ritonavir and double NRTI combination therapy respond to double PI nelfinavir/saquinavir and D4T rescue therapy only initially but have no sustained benefit.

[Focal mycobacterial lymphadenitis after starting highly active antiretroviral therapy]

HISTORY AND FINDINGS

A 30-year-old man with a known HIV infection for 7 years presented for treatment with antiretroviral drugs. He was known to have had herpes zoster, oral hairy leukoplakia and recurrent Candida stomatitis, but was otherwise without symptoms.

INVESTIGATIONS

The CD4 lymphocyte count was 19 cells/mm3 and there were 41,000 HIV-RNA copies/ml.

DIAGNOSIS, TREATMENT AND COURSE

The HIV infection was in CDC stage B3, indicating the need for combined antiretroviral treatment. A week after starting stavudine, saquinavir and ritonavir he had to be admitted because of nausea and vomiting, colicky abdominal pain, diarrhea, fever up to 39 degrees C and a rise of C-reactive protein to 207 mg/dl. Bacteriological examination of feces and biopsy of an enlarged retroperitoneal lymph node revealed atypical mycobacteria. Antituberculosis treatment was started. The CD4 cell count rose to 56/mm3 and the viral count fell to 11,000/ml. Each time after initiating a different antiviral regimen the symptoms recurred.

CONCLUSIONS

This case illustrates an atypical manifestation of on opportunistic infection: during combined antiviral treatment the CD4 cell count rose and thus precipitated an heretofore subclinical mycobacterial infection with focal lymphadenitis. If, on starting antiretroviral treatment at a late HIV stage, new symptoms develop within 1-3 weeks, one should consider drug-induced side effects or the onset of an opportunistic infection that has become manifest as the result of an improved immunological state.

Stavudine, lamivudine plus novel protease inhibitor therapy in antiretroviral-naive HIV-infected individuals treated for 24 weeks

Preliminary results are presented from a dose-comparison trial of the regimen stavudine/lamivudine plus the novel protease inhibitor, ABT-378/ritonavir, given to 101 antiretroviral-naive, human immunodeficiency virus (HIV)-infected subjects for > or = 24 weeks. The HIV-1 RNA had decreased to <400 copies/ml in 94% of patients and CD4 cell count had increased by approximately 160 cells/mm3 at 24 weeks. The regimen was well tolerated and merits further study.

Toxicokinetics of 2',3'-didehydro-3'-deoxythymidine, stavudine (D4T)

The toxicokinetic profile of D4T was assessed by conducting in vivo and in vitro studies. In the various studies, the i.v. and oral doses ranged from 12.5 to 600 and 5 to 2000 mg/kg, respectively. D4T was rapidly absorbed with an absolute oral bioavailability ranging from 77 to 100% in various species. The steady-state volume of distribution of D4T ranged from 0.50 to 1.12 liters/kg; radioactivity was distributed in all tissues, with the highest concentrations in the organs of excretion, liver and kidneys. D4T was eliminated from the body with a half-life of 0.30 to 1.23 h. Urinary recovery of unchanged drug was species-dependent and ranged from approximately 37 to 86%. In the mass balance studies, the recovery of total radioactivity at 96 h in rats and monkeys was approximately 85% and 50%, respectively; fecal recovery was <1.5% and approximately 14% was recovered as 14CO2 in expired air in rats. The in vitro protein binding of D4T was negligible (<10%) and D4T did not induce cytochrome P-450 in rats or monkeys. D4T was metabolized to thymine and polar metabolites by the S9 and liver slices in vitro. Significant interspecies correlations were found for total body clearance, steady state of volume of distribution, and T1/2 and species body weight. The multiples of exposure observed at the various no-effect doses in the drug safety evaluation studies (10x - 1102x) affirm that adequate doses of D4T were administered to laboratory animals to discern potential human risk.

Results of the ALBI trial: a randomized comparison of stavudine/didanosine, zidovudine/lamivudine and alternating treatment in antiretroviral-naive patients

In the ALBI trial, 151 antiretroviral-naive patients with plasma human immunodeficiency virus type 1 (HIV-1) RNA levels of 10,000 to 100,000 copies/ml and CD4 cell counts > or = 200 cells/mm3 received 24 weeks of treatment with stavudine/didanosine (n=51), zidovudine/lamivudine (n=51) or stavudine/didanosine for 12 weeks followed by zidovudine/lamivudine (n=49). Baseline plasma HIV-1 RNA and CD4 cell counts were comparable in the treatment groups. The mean decrease in plasma HIV-1 RNA at 24 weeks in the stavudine/didanosine group (2.26 log10) was significantly greater than that in either the zidovudine/lamivudine group (1.26 log10) or the alternating treatment group (1.58 log10) (P<0.0001 for both). Proportions of patients with plasma HIV-1 RNA level <500 copies/ml (91% vs 42% and 60%) and <50 copies/ml (47% versus 4% and 9%) were significantly greater in the stavudine/didanosine group (P<0.001 for pairwise comparisons). Stavudine/didanosine was associated with a mean increase in CD4 cell count (124 cells/mm3) significantly greater than that in the zidovudine/lamivudine group (62 cells/mm3, P<0.01) and comparable to that in the alternating group (118 cells/mm3). All study regimens were well tolerated. These findings, indicating superiority of stavudine/didanosine over zidovudine/lamivudine in virological and immunological response over 24 weeks, suggest that the combination should be considered as a basis for highly active antiretroviral therapy.

An open-label trial of stavudine, lamivudine and efavirenz in the treatment of HIV-positive, treatment-naive patients, and implications for clinical practice

A phase II, open-label study of stavudine, lamivudine and efavirenz resulted in significant reductions in plasma HIV-1 RNA over a 24 week period in human immunodeficiency virus (HIV)-infected individuals. The trial currently has 68 patients, and this presentation covers data on the first 42 patients enrolled for 24 weeks. The mean plasma HIV-1 RNA on entry was 75858 HIV RNA copies/ml, and the mean CD4 count was 380 cells/mm3. After 24 weeks, the CD4 count increased by 169 cells/mm3 above baseline. plasma HIV-1 RNA was markedly reduced: at 24 weeks, more than 97% of patients had <50 HIV RNA copies/ml based on observed data, and 89% of patients had <50 copies/ml based on strict intent-to-treat analysis (non-completer=failure). The favourable interactions of these agents resulted in no discontinuations owing to adverse effects. This regimen provides an important first-line treatment for antiretroviral-naive patients.

Stavudine, didanosine and nevirapine in antiretroviral-naive HIV-1-infected patients

In an ongoing, open-label, non-comparative study, the safety and efficacy of nevirapine/stavudine/didanosine were evaluated in 100 antiretroviral-naive adults with CD4 cell counts > or = 200 cells/mm3 and plasma HIV-1 RNA (pVL) > or = 5000 copies/ml. Sixty patients received nevirapine twice daily (VIRGO I) and 40 received nevirapine once daily (VIRGO II); all patients received didanosine once a day. After median follow-ups of 44 weeks in VIRGO I and 30 weeks in VIRGO II, the following virological results were observed (ongoing study): an intent-to-treat, non-completer equals failure analysis at week 24 showed the proportions of patients with pVL <500 copies/ml were 78% in VIRGO I (60% <50 copies/ml) and 75% in VIRGO II. An on-treatment analysis at week 52 showed 80% of patients with a pVL <500 copies/ml and 59% with <50 copies/ml in VIRGO I. The mean CD4 cell count increase was +171 cells/mm3 at week 24 and +218 cells/mm3 at week 52 in VIRGO I and +158 cells/mm3 at week 24 in VIRGO II. Cutaneous rash (grades 1 to 3) occurred in 24% of patients leading to nevirapine discontinuation in eight of 24 patients. Five other patients discontinued therapy during the first 24 weeks because of hepatic cytolysis, peripheral neuropathy or biological pancreatitis. The nevirapine/stavudine/didanosine combination is a convenient and safe regimen, with rapid and potent immunological and antiviral effects sustained over 12 months.

Treatment of primary HIV infection: a pilot study of stavudine and didanosine plus nevirapine with or without hydroxyurea

Treatment of primary human immunodeficiency virus (HIV) infection (PHI) may provide an opportunity to achieve a long lasting suppression of viral replication. Although there is growing evidence of the benefit of treating PHI, clinical data are still very limited. Special therapeutic considerations in this clinical setting include the prevalence of resistant viruses in the community, complexity of regimens and their long-term toxicity. In addition, adjunctive therapies aimed at exploring the role of immune modulation and intensification of antiretroviral therapy are becoming areas of great interest. In this regard, the role of hydroxyurea, a cytostatic agent that potentiates the antiviral effect of didanosine, and possibly of stavudine is being investigated. A pilot study to assess the antiviral effect of a combination of didanosine plus stavudine plus nevirapine with or without hydroxyurea in the treatment of PHI is currently under way. Preliminary results on 22 patients who completed at least 36 weeks of therapy suggest that the combination is safe, well tolerated and effective for the treatment of PHI.

Hydroxyurea: overview of clinical data and antiretroviral and immunomodulatory effects

Data from comparative trials involving more than 500 patients indicate that hydroxyurea is safe and augments suppression of HIV-1 replication when used in combination with didanosine or didanosine/stavudine as initial therapy or in patients without extensive antiretroviral experience. Additional studies will determine the optimum dosage and schedule for hydroxyurea and its effects when used with other agents and in patients with advanced disease or extensive pretreatment. Activities of hydroxyurea include inhibition of HIV-1 in active and resting CD4 lymphocytes and macrophages, potentiation of the activity of nucleoside reverse transcriptase inhibitors (NRTIs), compensation for resistance to adenosine analogue NRTIs, and potential increased phosphorylation of pyrimidine NRTIs. Recent attention, however, has focused on the potential immunomodulatory effects of hydroxyurea. The cytostatic effect of this agent on both CD4 and CD8 T cells may provide immunological benefits by reducing immune system overactivation, thus preventing both CD8 T cell exhaustion and CD4 T cell depletion. Accumulating evidence indicates that hydroxyurea-containing regimens may be associated with decreased levels of activated CD8 T cells, increased levels of naive CD4 and CD8 T cells, and preservation of the HIV-1-specific immune response. Further study of the potential for beneficial immunomodulation with hydroxyurea-containing regimens is needed to ascertain the clinical implications of these initial findings.