Discordance between virological, immunologic, and clinical outcomes of therapy with protease inhibitors among human immunodeficiency virus-infected patients

HIV disease and advanced age: an increasing therapeutic challenge

The mean age of patients at both first HIV detection and AIDS diagnosis is progressively rising over time. However, reliable epidemiological estimates, clinical data or controlled therapeutic and outcome figures are lacking for elderly patients, especially with regard to laboratory and clinical response to antiretroviral therapy, treatment tolerability, drug-drug interactions, short- and long-term toxicity, and interactions with underlying illnesses and concurrent pharmacological treatment. In fact, the large majority of randomised, controlled trials evaluating and comparing new antiretroviral drugs or anti-HIV therapeutic strategies, as well as antimicrobial treatment or chemoprophylaxis of HIV-related complications, either excluded patients with advanced age and/or concurrent disorders or did not offer substudies or detailed data analysis focusing on older patients compared with younger ones. The life expectancy of HIV-infected persons receiving highly active antiretroviral therapy (HAART) is now extended (approaching that of the general population), so that the definition of AIDS has lost its epidemiological and clinical significance thanks to the immune reconstitution resulting from potent antiretroviral therapy. However, an ever-increasing number of individuals aged > or =50 years with HIV infection is expected in the coming years, as a result of both increased survival of patients with treated disease and delayed recognition of individuals with occult HIV disease. The limited data available about combined antiretroviral therapy in the elderly seem to show an overlapping virological success rate but a slower and blunted immune recovery compared with younger patients. Thymic output, however, seems somewhat preserved even in adulthood and may contribute to the reconstitution of most of the quantitative and functional T cell abnormalities caused by HIV disease. More attention must be paid to underlying end-organ disorders, as well as expected pharmacological interactions and combined drug toxicity that may interfere with HAART efficacy and patients' compliance with recommended regimens and could lead to increased adverse effects. The available guidelines for antiretroviral treatment and therapy and prophylaxis of AIDS-related illnesses should be regularly updated and should include problems related to HIV disease in an aging population. Specific trials or substudies focusing on older people are warranted to obtain controlled data on all issues of antiretroviral therapy in the elderly, including time and mode of initiation, and modification and salvage HAART regimens. Antiretroviral drug dosage adjustment to take into account underlying pathological conditions or other pharmacological treatments is another emerging issue.

Durability and predictors of success of highly active antiretroviral therapy for ambulatory HIV-infected patients

OBJECTIVE

To evaluate the durability and correlates of the effectiveness of highly active antiretroviral therapy (HAART) in terms of AIDS-related mortality and morbidity, HIV viremia, and CD4 cell count.

DESIGN AND SETTING

The HIV Outpatient Study (HOPS), a prospective observational cohort from eight clinics in the USA that has been running since 1994.

PARTICIPANTS

Mortality and opportunistic infection (OI) rates were calculated for 1769 HOPS patients with CD4 cell count ever < 100 x 106/l. Data from 1022 HAART recipients with CD4 cell count ever < 500 x 106/l were analyzed.

MAIN OUTCOME MEASURES

Mortality and AIDS-related OI rates. Treatment success was defined as a reduction in plasma HIV RNA copies/ml of 1.0 log10 or more, or to an undetectable level, with a stable or rising CD4 cell count. Durable success was a successful response lasting at least 12 consecutive months.

RESULTS

HAART use remained high; mortality and OIs low. Patients received a mean of 1.8 HAART regimens. Median time on first HAART (n = 1022) was 11.8 months; second HAART (n = 424) 7.4 months; and third HAART (n = 213) 7.2 months. Treatment success was most likely for pre-HAART treatment naive patients; durably successful first HAART most often contained one protease inhibitor, particularly indinavir or nelfinavir (P = 0.006, adjusted for prior antiretroviral therapy). Durable success was most likely with first (49.0%) than with second (29.6%, P = 0.013) or third or more HAART regimens (14.9%, P < 0.0001). Time to success with first HAART was shorter for durable than non-durable responders (3.6 versus 5.3 months, respectively; unadjusted P = 0.002).

CONCLUSIONS

Durable response to HAART was associated with being pre-HAART therapy naive, prompt response to HAART, and single protease inhibitor-based initial HAART (indinavir or nelfinavir). Sequential HAART regimens were of progressively shorter duration, demonstrated less viral suppression and CD4 cell count benefit, yet low morbidity and mortality rates were sustained.

Antiviral potency of HAART regimens and clinical success are not strictly coupled in real life conditions: evidence from the MASTER-1 study

PURPOSE

To compare in a real clinical setting the largely unknown midterm clinical effectiveness of two protease inhibitor (PI)-based highly active antiretroviral therapy (HAART) regimens with different potency and tolerability profiles in naïve patients.

METHOD

This study was a multicenter, open-label, randomized trial in naïve patients with less than 400 CD4+ cell count/microL, regardless of viral load. Treatment arms were hard gel capsule saquinavir (HGC-SQV)-based HAART (Arm A), with an expected more favorable tolerability profile, and indinavir (IDV)-based HAART (Arm B), with more potent virologic activity. While viro-immunological surrogate markers and World Health Organization (WHO) grade III toxicity (secondary endpoints) were regularly monitored, primary endpoints of the study were clinical and defined as any AIDS-defining event, AIDS-related death, WHO grade IV toxicity, drop outs, and protocol violations.

RESULTS

262 consecutive patients were enrolled in the study from March 1, 1997 to December 31, 1997, in 24 different Italian clinical centers (132, Arm A; 130, Arm B). After 24 months of follow-up, patients who were enrolled in Arm B showed a significantly higher rate of virological success (75% had viremia below 500 copies/mL, CI = 12.9%, in the on-treatment analysis) and immunological gain (mean CD4+ cell count increase of 274 CD4+ cells/microL, SD = 234) when compared to patients enrolled in arm A (57%, CI = 15.5% and 223 CD4+ cells/microL, SD = 192; p =.0353 and.026, respectively). Despite the significant difference observed in surrogate markers, the number of total primary endpoints did not differ in the two groups (55 out of 132 in Arm A vs. 58 out of 130 person-years in Arm B; p =.86).

CONCLUSION

Our results suggest that, after 24 months of follow-up in a real clinical setting, a PI-based HAART induces significant clinical benefits in naïve patients even in the absence of a complete suppression of viral replication. However, the long-term clinical impact of the possible accumulation of viral mutations in the presence of low-grade viral replication remains to be elucidated.