A randomized trial comparing the introduction of ritonavir or indinavir in 1251 nucleoside-experienced patients with advanced HIV infection

ISS-IP1, a multicenter, randomized, 48-week open trial, was designed to compare the introduction of ritonavir or indinavir in patients with previous nucleoside experience and CD4+ cell counts below 50/mm3. Concomitant antiretroviral treatment with nucleoside analogs was allowed. Primary efficacy measures were survival and time to a new AIDS-defining event or death, analyzed through the whole period of observation by the intention-to-treat approach. Primary toxicity measures were time to treatment discontinuation and adverse events, grade at least 3/serious, analyzed by an on-treatment approach. Evaluation-of efficacy also included CD4+ cell and RNA response. The trial enrolled 1251 patients in 5 months. At baseline, mean CD4+ cell count was about 20 cells/mm3 and mean HIV RNA copy number was 4.9 log10/ml in both groups. Overall, 402 patients in the ritonavir group and 250 patients in the indinavir group permanently discontinued the assigned treatment (relative risk, 1.96; 95% CI, 1.68-2.30; p = 0.0001), with most of this difference dependent on a higher number of discontinuation for adverse events in the ritonavir group. After a mean follow-up of 307 days (ritonavir, 304; indinavir, 309), 124 deaths (ritonavir, 61; indinavir, 63; relative risk, 0.96; 95% CI, 0.67-1.36; p = 0.80) and 330 new AIDS-defining events (ritonavir, 170; indinavir, 160; relative risk, 1.05; 95% CI, 0.85-1.31; p = 0.60) were observed. CD4+ cell counts increased in both groups in patients still receiving treatment, with about 100 cells gained by week 24 and 150 cells gained by week 48. Body weight also increased over time in both groups. Analysis of RNA response showed a decrease of 1.5 log10 or higher in both treatment groups. Overall, 400 patients in the ritonavir group and 338 patients in the indinavir group developed at least one grade 3/serious new adverse event during follow-up (relative risk, 1.48; 95% CI, 1.28-1.72; p = 0.0001). Favorable CD4+ cell and RNA responses at 24 and 48 weeks were observed in both groups of patients remaining on treatment. Indinavir showed slightly better effects in sustaining RNA, CD4+ cell, and body weight responses. Ritonavir and indinavir results were comparable in terms of clinical outcome (survival and AIDS-defining events).

Delavirdine in combination with zidovudine in treatment of human immunodeficiency virus type 1-infected patients: evaluation of efficacy and emergence of viral resistance in a randomized, comparative phase III trial. The M/3331/0013B Study Group

We compared the activity of delavirdine (DLV) plus zidovudine (AZT) (n = 300) with that of AZT (n = 297) against human immunodeficiency virus type 1 in a randomized, double-blind, placebo-controlled trial. DLV exerted a transient antiviral effect, and mutations for resistance to DLV were found in more than 90% of subjects at week 12. The K103N mutation, which confers nonnucleoside reverse transcriptase inhibitor cross-resistance, was found in 85% of the patients.

Nosocomial candidemia in non-neutropenic patients at an Italian tertiary care hospital

In a retrospective study conducted in an Italian tertiary care hospital, the incidence of nosocomial candidemia was evaluated together with causative pathogens, treatment, and risk factors for death. Over a 6-year period (1992-1997), a total of 189 episodes of candidemia occurred in 189 patients (mean age 58+/-19 years), accounting for an average incidence of 1.14 episodes per 10,000 patient-days per year. The most common reasons for hospitalization were solid neoplasia (21%), trauma (17%), abdominal diseases requiring surgery (13%), and cardiovascular diseases (13%). No patient was neutropenic within 3 weeks prior to the onset of candidemia. One hundred thirty patients were hospitalized in intensive care units, 47 patients in surgical wards, and 12 patients in medical wards. Candida albicans was the most frequently isolated pathogen, accounting for 54% of fungal isolates, followed by Candida parapsilosis (23%), Candida glabrata (7%), Candida tropicalis (5%), Candida pelliculosa (4%), Candida lusitaniae (1%), Candida humicula (1%), and other non-albicans Candida spp. (5%). Seventy-six (41%) patients received adequate antifungal therapy. Seventy-one (58%) of the 123 evaluable patients with central venous catheters underwent line removal; 51 of them had catheter-related candidemia. The 30-day crude mortality rate was 45%. Older age, hospitalization in an intensive care unit, a longer duration of candidemia, retention of central lines, and inadequate antifungal therapy were significantly associated with poor outcome. In the present study, nosocomial candidemia was a frequent and relatively underestimated illness. Adequate antifungal therapy and central line removal independently reduced the high mortality of the disease.

Concentrations of single-dose meropenem (1 g iv) in bronchoalveolar lavage and epithelial lining fluid

The concentrations of meropenem were measured in plasma, bronchoalveolar lavage (BAL) and epithelial lining fluid (ELF) 0.5-8 h after the administration of a single 1 g iv dose of meropenem. Thirty-five patients undergoing bronchoscopy were studied. Mean concentrations in plasma, BAL and ELF, respectively, measured by high performance liquid chromatography, were as follows: 0.5 h: 25. 96, 0.14, 5.04 mg/L; 1 h: 14.98, 0.09, 7.07 mg/L; 2 h: 12.01, 0.06, 3.86 mg/L; 4 h: 2.51, 0.04, 2.20 mg/L; 6 h: 0.57, 0, 0.59 mg/L; 8 h: 0.29, 0, 0 mg/L. Throughout the 2 h following infusion, concentrations in ELF exceeded the MIC90 for all nosocomial and community-acquired respiratory pathogens, including Pseudomonas aeruginosa (3.05 mg/L), Haemophilus influenzae (0.16 mg/L) and penicillin-resistant Streptococcus pneumoniae (0.86 mg/L). These results support the clinical efficacy of meropenem in the treatment of a wide range of pulmonary infections.

Discontinuation of primary prophylaxis for Pneumocystis carinii pneumonia and toxoplasmic encephalitis in human immunodeficiency virus type I-infected patients: the changes in opportunistic prophylaxis study

A multicenter open, randomized, controlled trial was conducted to determine whether primary prophylaxis for Pneumocystis carinii pneumonia and toxoplasmic encephalitis can be discontinued in patients infected with human immunodeficiency virus type 1 (HIV-1) whose CD4+ T cell counts have increased to >200 cells/mm3 (and who have remained at this level for at least 3 months) as a result of highly active antiretroviral therapy (HAART). Patients were randomized to either the discontinuation arm (i.e., those who discontinued prophylaxis; n=355) or to the continuation arm (n=353); the 2 arms of the study were similar in terms of demographic, clinical, and immunovirologic characteristics. During the median follow-ups of 6.4 months (discontinuation arm) and 6.1 months (continuation arm) and with a total of 419 patient-years, no patient developed P. carinii pneumonia or toxoplasmic encephalitis. The results of this study strongly indicate that primary prophylaxis for P. carinii pneumonia and toxoplasmic encephalitis can be safely discontinued in patients whose CD4+ T cell counts increase to >200 cells/mm3 during HAART.

Pharmacokinetics and tissue penetration of vancomycin in patients undergoing prosthetic mammary surgery

Vancomycin concentrations in periprosthetic breast tissues were evaluated in 24 women undergoing reconstructive surgery after mastectomy for breast cancer. Patients were given a single prophylactic dose of vancomycin (1 g iv) 1-8 h before surgery, and mean capsular and pericapsular tissue concentrations were measured by HPLC. Vancomycin was not detectable in the majority of patients belonging to the 1-3 h post-dose groups, whereas in the 4-8 h post-dose groups, mean capsular and pericapsular concentrations were as follows: at 4 h, 4.0 mg/kg and 5.9 mg/kg; at 6 h, 4.1 mg/kg and 4. 8 mg/kg; at 8 h, 5.9 mg/kg and 11.1 mg/kg, respectively. Vancomycin tissue concentrations thus were equal to or exceeded the breakpoint of 4 mg/L in most samples collected 4-8 h after dosing. In conclusion, our data suggest that appropriate timing of vancomycin prophylaxis should be considered to allow the maintenance of adequate tissue concentrations throughout the surgical procedure.

Cellular proviral HIV-DNA decline and viral isolation in naïve subjects with <5000 copies/ml of HIV-RNA and >500 x 10(6)/l CD4 cells treated with highly active antiretroviral therapy

OBJECTIVE

To evaluate the decay rate of cellular proviral HIV-DNA and viral replication in patients receiving highly active antiretroviral therapy (HAART) in the very early phase of infection.

METHODS

Thirty-four patients treated with HAART and retrospectively selected for progressive decline of plasma viraemia up to undetectable levels (< 20 copies/ml), were stratified according to CD4+ cell count and plasma viraemia at base line: > 500 x 10(6) cells/l with < 5000 copies/ml (group 1) or with > 5000 copies/ml (group 2), > 5000 copies/ml with 300-500 x 10(6) cells/l (group 3) or with < 300 x 10(6) cells/l (group 4). Plasma HIV-RNA and proviral HIV-DNA were analysed at baseline and after 1, 2, 3, 6, 9 and 12 months of treatment.

RESULTS

After 1 year of treatment, a significant decrease of proviral DNA titre was observed in all patients and a decrease > 1 log was achieved in 24 of 29 subjects of the first three groups. The more pronounced decay of HIV-DNA (half-life 28 weeks) up to < 50 HIV-DNA copies/10(6) CD4+ cells was detected in patients of group 1. At the year's endpoint, five patients (four in group 1 and one in group 2) had < 20 HIV-DNA copies. However, HIV strains sensitive to antiretroviral drugs were isolated from peripheral lymphocytes of 16 out of 34 patients.

CONCLUSION

In patients with undetectable plasma viraemia after 1 year of HAART, the highest reduction of proviral DNA up to < 50 copies/10(6) CD4+ cells was obtained only in subjects in the early asymptomatic phase of infection. Nevertheless, a replication-competent virus can be detected in all phases of antiretroviral therapy.

Recovery of long-term natural protection against reactivation of CMV retinitis in AIDS patients responding to highly active antiretroviral therapy

OBJECTIVES

To see whether in severely immunosuppressed AIDS patients (with prior Cytomegalovirus retinal disease) who have significant increases in CD4+ lymphocytes following the initiation of highly active antiretroviral therapy (HAART) anti-Cytomegalovirus (CMV) maintenance therapy can be withdrawn with no subsequent progression of CMV retinitis.

METHODS

Eight patients with AIDS and one or more previous episodes of CMV retinitis interrupted anti-CMV maintenance therapy following the successful beginning of HAART. CD4 cell counts and HIV-RNA were monitored monthly while measurement of CMV antigenemia and ophthalmoscopy were carried every 2 weeks thereafter.

RESULTS

The HAART recipients in whom anti-CMV maintenance therapy had been interrupted had measureable increases of CD4+ T lymphocytes, substantial control of both HIV-RNA and CMV viraemia and did not show recurrence of retinitis during a mean follow-up of 98.4 weeks (range 78-120, SD 15.2).

CONCLUSIONS

Anti-CMV maintenance therapy can be interrupted with no subsequent progression of retinal damage over a long time in patients with AIDS who successfully respond to HAART with a significant increase in CD4 cell count.

Comparative evaluation of ligation-mediated PCR and spoligotyping as screening methods for genotyping of Mycobacterium tuberculosis strains

Spoligotyping has been suggested as a screening test in multistep genotyping of Mycobacterium tuberculosis strains. Relying on restriction fragment length polymorphism (RFLP) analysis with IS6110 (IS6110 RFLP analysis) as a "gold standard," we performed a comparative evaluation of spoligotyping and ligation-mediated PCR (LMPCR), a recently described PCR-based typing method, as rapid screening tests for fingerprinting of 158 M. tuberculosis strains collected in Verona, Italy. LMPCR seemed to be comparable to spoligotyping in terms both of feasibility with rapidly extracted DNA and of generation of software-analyzable images. Moreover, LMPCR grouped considerably fewer strains than spoligotyping (38 versus 67%) and was found to reduce the cluster overestimation rate (26.3 versus 58%) and to give a better discriminatory index (0.992 versus 0.970) compared to spoligotyping. In our geographical region, where there was no evidence of clustered strains carrying fewer than six IS6110 copies, LMPCR was found to be more discriminatory than spoligotyping. We also evaluated two models of three-step typing strategies, involving the use of spoligotyping and LMPCR as screening methods and IS6110 RFLP analysis as a further supporting test. LMPCR proved to be a more effective first-step test than spoligotyping, significantly reducing the need for subtyping. LMPCR should be considered an alternative to spoligotyping as a rapid screening method for M. tuberculosis fingerprinting, particularly in areas with a low prevalence of M. tuberculosis strains carrying few copies of IS6110.

Rapid absorption and clinical effectiveness of intragastric mefloquine in the treatment of cerebral malaria in African children

To obviate the lack of injectable quinine in a hospital in rural Burundi, mefloquine, only available as an oral formulation, was administered (25 mg/kg bodyweight) as a single dose by nasogastric tube to four small children with cerebral malaria. All patients recovered uneventfully after a mean coma duration of 20.5 h. Mefloquine was rapidly absorbed and therapeutic serum concentrations were achieved within a few hours in all subjects, with parasite reduction ratios after 48 h within the expected range for drug-sensitive parasites. These findings suggest that intragastric mefloquine deserves consideration whenever parenteral drugs are not available for the treatment of cerebral malaria.

Heteroresistance to fluconazole and voriconazole in Cryptococcus neoformans

Cryptococcus neoformans isolates that exhibited unusual patterns of resistance to fluconazole and voriconazole were isolated from seven isolates from two different geographical regions: one isolate from an Israeli non-AIDS patient and six serial isolates from an Italian AIDS patient who had suffered six recurrent episodes of cryptococcal meningitis. Each isolate produced cultures with heterogeneous compositions in which most of the cells were susceptible, but cells highly resistant to fluconazole (MICs, >/=64 microg/ml) were recovered at a variable frequency (7 x 10(-3) to 4.6 x 10(-2)). Evidence showed that this type of resistance is innate and is unrelated to drug exposure since the Israeli patient had never been treated with azoles or any other antimycotic agents. Analysis of clonal subpopulations of these two strains showed that they exhibited heterogeneous patterns of resistance. The number of subpopulations which grew on fluconazole or voriconazole agar declined progressively with increasing azole concentration without a sharp cutoff point. For the Italian serial isolates, the number of clonal populations resistant to fluconazole (64 microg/ml) and voriconazole (1 microg/ml) increased steadily, yielding the highest number for the isolate from the last episode. Attempts to purify a sensitive subpopulation failed, but clones highly resistant to fluconazole (100 microg/ml) and moderately resistant to voriconazole (1 microg/ml) always produced a homogeneous population of resistant cells. Upon maintenance on drug-free medium, however, the majority of the homogeneously resistant cells of these subclones lost their resistance and returned to the stable initial heteroresistant phenotype. The pattern of heteroresistance was not affected by the pH or osmolarity of the medium but was influenced by temperature. The resistance appeared to be suppressed at 35 degrees C and was completely abolished at 40 degrees C. Although heterogeneity in azole resistance among subpopulations of single isolates has been reported for Candida species, the transient changes in expression of resistance under different growth conditions reported here have not been observed in fungal pathogens.

Failure of prophylaxis against PCP in patients with HIV infection

Since the end of the 1980s, primary anti-Pneumocystis carinii pneumonia (PCP) prophylaxis has become a fundamental part of the global AIDS control strategy in industrialized countries. The widespread adoption of anti-PCP chemoprophylaxis has been a key element in prolonging the survival of patients with AIDS. There is general agreement on the need to begin chemoprophylaxis when individual CD4+ cell counts drop below the value of 200/microL. However, PCP still develops in up to 27% of susceptible HIV-infected patients despite regular prophylaxis intake. Failure of chemoprophylaxis may depend on different factors. The choice of the regimen and the patient's compliance to it have been the first variables to be identified, whereas the importance of the residual cellular immune function as complementary protective mechanism against PCP has emerged in subsequent clinical studies. Albeit of limited general concern, issues such as P. carinii drug resistance and defective drug absorption may play some role in prophylaxis failure in selected patients. Regarding the epidemiology of primary and recurrent episodes of PCP, recent studies based on genetic fingerprinting techniques revealed that interhuman transmission of the organism could be more relevant than so far expected, thus raising some concern of the possibility of nosocomial spread among susceptible individuals. The downgrading tendency of immune competence in HIV infection and the related increasing risk of developing PCP make it possible to envisage a two-step chemoprophylactic strategy, with the most effective compound, cotrimoxazole, to be reserved for the last and most risky disease stage, when immune response no longer provides any support for preventing the development of PCP.