Long-acting cabotegravir and rilpivirine dosed every 2 months in adults with HIV-1 infection (ATLAS-2M), 48-week results: a randomised, multicentre, open-label, phase 3b, non-inferiority study

BACKGROUND

Phase 3 clinical studies showed non-inferiority of long-acting intramuscular cabotegravir and rilpivirine dosed every 4 weeks to oral antiretroviral therapy. Important phase 2 results of every 8 weeks dosing, and supportive modelling, underpin further evaluation of every 8 weeks dosing in this trial, which has the potential to offer greater convenience. Our objective was to compare the week 48 antiviral efficacy of cabotegravir plus rilpivirine long-acting dosed every 8 weeks with that of every 4 weeks dosing.

METHODS

ATLAS-2M is an ongoing, randomised, multicentre (13 countries; Australia, Argentina, Canada, France, Germany, Italy, Mexico, Russia, South Africa, South Korea, Spain, Sweden, and the USA), open-label, phase 3b, non-inferiority study of cabotegravir plus rilpivirine long-acting maintenance therapy administered intramuscularly every 8 weeks (cabotegravir 600 mg plus rilpivirine 900 mg) or every 4 weeks (cabotegravir 400 mg plus rilpivirine 600 mg) to treatment-experienced adults living with HIV-1. Eligible newly recruited individuals must have received an uninterrupted first or second oral standard-of-care regimen for at least 6 months without virological failure and be aged 18 years or older. Eligible participants from the ATLAS trial, from both the oral standard-of-care and long-acting groups, must have completed the 52-week comparative phase with an ATLAS-2M screening plasma HIV-1 RNA less than 50 copies per mL. Participants were randomly assigned 1:1 to receive cabotegravir plus rilpivirine long-acting every 8 weeks or every 4 weeks. The randomisation schedule was generated by means of the GlaxoSmithKline validated randomisation software RANDALL NG. The primary endpoint at week 48 was HIV-1 RNA ≥50 copies per mL (Snapshot, intention-to-treat exposed), with a non-inferiority margin of 4%. The trial is registered at ClinicalTrials.gov, NCT03299049 and is ongoing.

FINDINGS

Screening occurred between Oct 27, 2017, and May 31, 2018. Of 1149 individuals screened, 1045 participants were randomised to the every 8 weeks (n=522) or every 4 weeks (n=523) groups; 37% (n=391) transitioned from every 4 weeks cabotegravir plus rilpivirine long-acting in ATLAS. Median participant age was 42 years (IQR 34-50); 27% (n=280) female at birth; 73% (n=763) white race. Cabotegravir plus rilpivirine long-acting every 8 weeks was non-inferior to dosing every 4 weeks (HIV-1 RNA ≥50 copies per mL; 2% vs 1%) with an adjusted treatment difference of 0·8 (95% CI -0·6-2·2). There were eight (2%, every 8 weeks group) and two (<1%, every 4 weeks group) confirmed virological failures (two sequential measures ≥200 copies per mL). For the every 8 weeks group, five (63%) of eight had archived non-nucleoside reverse transcriptase inhibitor resistance-associated mutations to rilpivirine at baseline. The safety profile was similar between dosing groups, with 844 (81%) of 1045 participants having adverse events (excluding injection site reactions); no treatment-related deaths occurred.

INTERPRETATION

The efficacy and safety profiles of dosing every 8 weeks and dosing every 4 weeks were similar. These results support the use of cabotegravir plus rilpivirine long-acting administered every 2 months as a therapeutic option for people living with HIV-1.

FUNDING

ViiV Healthcare and Janssen.

"I feel empowered": women's perspectives on and experiences with long-acting injectable antiretroviral therapy in the USA and Spain

Long-acting injectable antiretroviral therapy has been shown to be non-inferior to daily oral antiretroviral therapy in clinical trials and may soon become part of clinical care. While most trial participants to date have been men, approximately one quarter of ongoing Phase 3 trial participants are women offering an important opportunity to understand how long-acting antiretroviral therapy is perceived and experienced by women. We conducted in-depth interviews with 80 people living with HIV participating in Phase 2 and 3 clinical trials of long-acting antiretroviral therapy in the USA and Spain. Fifteen percent (12/80) of trial participants interviewed were women. Interviews were audio-recorded, transcribed and coded using content analysis, focused on gender-specific themes. Women shared many of the positive perceptions expressed by men but also had unique perspectives, including finding that long-acting antiretroviral therapy addressed the challenge of remembering pills amidst busy day-to-day realities including multiple roles and responsibilities, is less time consuming and creates less stress compared to oral antiretroviral therapy, and is emotionally freeing and empowering. The gendered nature of women's lives shaped why and how they were satisfied with long-acting antiretroviral therapy. Findings can inform interventions and support systems to facilitate uptake of and adherence to long-acting antiretroviral therapy in women.

New genetic predictors for abacavir tolerance in HLA-B*57:01 positive individuals

Abacavir hypersensitivity syndrome (ABC HSS) is strongly associated with carriage of human leukocyte antigen (HLA)-B*57:01, which has a 100% negative predictive value for the development of ABC HSS. However, 45% of individuals who carry HLA-B*57:01 can tolerate ABC. We investigated immune and non-immune related genes in ABC HSS (n = 95) and ABC tolerant (n = 43) HLA-B*57:01 + patients to determine other factors required for the development of ABC HSS. Assignment of phenotype showed that ABC HSS subjects were significantly less likely than tolerants to carry only ERAP1 hypoactive trimming allotypes (p = 0.02). An altered self-peptide repertoire model by which abacavir activates T cells is in keeping with observation that endoplasmic reticulum aminopeptidase 1 (ERAP1) allotypes that favour efficient peptide trimming are more common in ABC HSS patients compared to patients who tolerate ABC. Independently, non-specific immune activation via soluble cluster of differentiation antigen 14 (sCD14) may also influence susceptibility to ABC HSS.

Abacavir Use and Risk for Myocardial Infarction and Cardiovascular Events: Pooled Analysis of Data From Clinical Trials

Background

Some observational studies and randomized controlled trials (RCTs) have suggested an association between abacavir (ABC) use and myocardial infarction (MI), whereas others have not.

Methods

This pooled analysis of 66 phase II–IV RCTs estimates exposure-adjusted incidence rates (IRs) and relative rates (RRs) of MI and cardiovascular events (CVEs) in participants receiving ABC- and non-ABC-containing combination antiretroviral therapy (cART). The primary analysis of MI included ABC-randomized trials with ≥48-week follow-up. Sensitivity analyses of MI and CVEs included non-ABC-randomized and <48-week follow-up trials.

Results

In 66 clinical trials, 13 119 adults (75% male, aged 18–85 years) were on ABC-containing cART and 7350 were not. Exposure-adjusted IR for MI was 1.5 per 1000 person-years (PY; 95% confidence interval [CI], 0.67–3.34) in the ABC-exposed group and 2.18 per 1000 PY (95% CI, 1.09–4.40) in the unexposed group. The IR for CVEs was 2.9 per 1000 PY (95% CI, 2.09–4.02) in the exposed group and 4.69 per 1000 PY (95% CI, 3.40–6.47) in the unexposed group with studies of ≥48 weeks of follow-up, with an RR of 0.62 (95% CI, 0.39–0.98). The inclusion of nonrandomized and shorter-duration trials did not significantly change the RR for MI or coronary artery disease.

Conclusions

This pooled analysis found comparable IRs for MI and CVEs among ABC-exposed and -unexposed participants, suggesting no increased risk for MI or CVEs following ABC exposure in a clinical trial population. Modifiable risk factors for MI and CVEs should be addressed when prescribing ART.

Effect of Sorbitol on the Pharmacokinetic Profile of Lamivudine Oral Solution in Adults: An Open-Label, Randomized Study

In children aged ≤4 years, the relative bioavailability of lamivudine oral solution was 37% lower than that of a tablet formulation. An open-label, four-way crossover study was conducted in healthy adults to evaluate the effect of sorbitol, a common liquid excipient, on the pharmacokinetics of lamivudine oral solution (ClinicalTrials.gov identifier, NCT02634073). Sixteen subjects were randomized to one of four sequences consisting of four doses of lamivudine 300 mg (10 mg/mL) alone or with sorbitol 3.2, 10.2, or 13.4 g. Sorbitol 3.2, 10.2, and 13.4 g decreased lamivudine maximum concentration (C_max ) by 28%, 52%, and 55% and area under the concentration-time curve from time 0 to 24 h (AUC_0-24 ) by 20%, 39%, and 44%, respectively. Three subjects (19%) reported five nonserious adverse events (one drug-related). The dose-dependent effects of sorbitol on lamivudine C_max and AUC_0-24 reveal an absorption-based interaction that may decrease lamivudine exposure in patients coadministered sorbitol-containing medicines.

Hepatic safety profile of fosamprenavir-containing regimens in HIV-1-infected patients with or without hepatitis B or C coinfection

PURPOSE

This post hoc analysis investigated the hepatic safety profile of fosampre-navir (FPV) in patients monoinfected with HIV or coinfected with HIV and hepatitis B (HbsAg positive) and/or hepatitis C (anti-HCV antibody positive).

METHODS

Data were pooled from 7 prospective, randomized clinical trials of FPV.

RESULTS

Baseline demographics were generally well-matched between the 205 coinfected (72% HCV, 24% HBV, 3% both) and 1,114 monoinfected patients in this analysis. At baseline, most regimens included ritonavir 100 mg (58%) or 200 mg (38%), and 73% of subjects were ART-naïve. Over 48 weeks, the rate of treatment-related serious adverse events was similar between the coinfected (8%; 16/205) and monoinfected (6%; 62/1114) groups, and the rate of treatment-related grade 2-4 adverse events was higher in the coinfected (38%; 77/205) compared with the monoinfected (29%; 320/1114) group. The percentage of patients with grade 3/4 liver enzyme elevations at any time through week 48 was 14% (ALT) and 12% (AST) in the coinfected group and 1% (both ALT and AST) in the monoinfected group. Median AST to platelet ratio index (APRI) scores decreased by 29% in both groups.

CONCLUSION

Liver enzyme elevations in coinfected patients treated with FPV with or without ritonavir appear generally similar to those reported for other second-generation protease inhibitors.

A study of HIV provider attitudes toward HLA-B 5701 testing in the United States

Screening for HLA-B 5701 reduces the risk of developing an abacavir hypersensitivity reaction (ABC HSR) and is recommended in all patients before initiating highly active antiretroviral therapy (HAART) with abacavir. Between September 2007 and March 2008 we conducted a study of the attitudes and practice patterns of HIV providers in the United States to identify barriers to HLA-B 5701 testing in clinical practice. Study participants who completed an educational program could receive HLA-B 5701 test kits for use in their clinical practice. Surveys were administered before and after the educational program. A total of 477 HIV providers registered to participate in the survey, and 134 providers tested a total of 874 HIV-infected subjects, of which 6% (49/874) were HLA-B 5701 positive. Of 433 providers who completed the preeducation survey, 97% indicated that the test provided clinical value and 77% anticipated barriers to testing, with cost/reimbursement the most frequently cited. Among 202 providers who completed the posteducation survey, perceptions of the test's value remained largely unchanged while the proportion of providers who anticipated or encountered barriers to testing decreased. Of providers who used HLA-B 5701 test kits, 86% (115/134) found it "very easy" or "easy" to obtain test results, 95% (127/134) found it "very easy" or "easy" to interpret results, and 89% (119/134) indicated that they planned to continue HLA-B 5701 testing after the study. The results of this study suggest that HLA-B 5701 testing is easy to use in clinical practice and is a valuable tool to help reduce the risk of developing ABC HSR.

Prevalence of antiretroviral drug resistance and resistance-associated mutations in antiretroviral therapy-naïve HIV-infected individuals from 40 United States cities

BACKGROUND

Transmission of drug-resistant HIV strains to antiretroviral therapy (ART)-naïve subjects can negatively impact therapy response. As treatment strategies and utilization of antiretroviral drugs evolve, patterns of transmitted mutations may shift.

METHOD

Paired genotypic and phenotypic susceptibility data were retrospectively analyzed for 317 ART-naïve, HIV-infected subjects from 40 small and major metropolitan cities in the Northeastern, Midwestern, Southern, Southwestern, and Northwestern United States during 2003.

RESULTS

Using current (January 2007) PhenoSense cutoffs, HIV-from 8% of subjects had reduced susceptibility to > or = 1 drug. By class, < 1% had reduced susceptibility to protease inhibitors (PIs), and 1% had reduced susceptibility to nucleoside reverse transcriptase inhibitors (NRTIs); reduced susceptibility to > or = 1 non-nucleoside reverse transcriptase inhibitor (NNRTIs) was seen in 7% of subjects, with 4% of all subjects having reduced susceptibility to all NNRTIs. IAS-USA-defined NRTI, NNRTI, and/or major PI HIV-drug resistance-associated mutations were detected for 0% of the subjects. HIV risk factors included homosexual contact (74%), heterosexual contact (28%), and injectable drug use/transfusion/other (7%). Reduced susceptibility to > or = 1 drug was significantly higher (p = .034) for white subjects than African Americans and Hispanics/others.

CONCLUSION

The high prevalence of drug resistance in these ART-naïve subjects suggests that transmitted resistance is occurring widely within the United States. HIV genotyping and/or phenotyping for antiretroviral-naïve patients seeking treatment should be considered, especially if the therapy will include an NNRTI.

The KLEAN study of fosamprenavir-ritonavir versus lopinavir-ritonavir, each in combination with abacavir-lamivudine, for initial treatment of HIV infection over 48 weeks: a randomised non-inferiority trial

BACKGROUND

Lopinavir-ritonavir is a preferred protease inhibitor co-formulation for initial HIV-1 treatment. Fosamprenavir-ritonavir has shown similar efficacy and safety to lopinavir-ritonavir when each is combined with two nucleoside reverse transcriptase inhibitors. We compared the two treatments directly in antiretroviral-naive patients.

METHODS

This open-label, non-inferiority study included 878 antiretroviral-naive, HIV-1-infected patients randomised to receive either fosamprenavir-ritonavir 700 mg/100 mg twice daily or lopinavir-ritonavir 400 mg/100 mg twice daily, each with the co-formulation of abacavir-lamivudine 600 mg/300 mg once daily. Primary endpoints were proportion of patients achieving HIV-1 RNA less than 400 copies per mL at week 48 and treatment discontinuations because of an adverse event. The intent-to-treat analysis included all patients exposed to at least one dose of randomised study medication. This study is registered with ClinicalTrials.gov, number NCT00085943.

FINDINGS

At week 48, non-inferiority of fosamprenavir-ritonavir to lopinavir-ritonavir (95% CI around the treatment difference -4.84 to 7.05) was shown, with 315 of 434 (73%) patients in the fosamprenavir-ritonavir group and 317 of 444 (71%) in the lopinavir-ritonavir group achieving HIV-1 RNA less than 400 copies per mL. Treatment discontinuations due to an adverse event were few and occurred with similar frequency in the two treatment groups (fosamprenavir-ritonavir 53, 12%; lopinavir-ritonavir 43, 10%). Diarrhoea, nausea, and abacavir hypersensitivity were the most frequent drug-related grade 2-4 adverse events. Treatment-emergent drug resistance was rare; no patient had virus that developed reduced susceptibility to fosamprenavir-ritonavir or lopinavir-ritonavir.

INTERPRETATION

Fosamprenavir-ritonavir twice daily in treatment-naive patients provides similar antiviral efficacy, safety, tolerability, and emergence of resistance as lopinavir-ritonavir, each in combination with abacavir-lamivudine.

Abacavir and lamivudine fixed-dose combination tablet once daily compared with abacavir and lamivudine twice daily in HIV-infected patients over 48 weeks (ESS30008, SEAL)

BACKGROUND

Abacavir (ABC) and lamivudine (3TC) administered twice daily were compared with an ABC + 3TC fixed-dose combination (Epzicom, Kivexa; EPZ) administered once daily, both in combination with a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI).

METHODS

Two hundred sixty HIV-infected subjects with more than 6 months of ABC and 3TC administered twice daily plus a PI or NNRTI with an HIV-1 RNA level less than 400 copies/mL for more than 3 months and a CD4 count greater than 50 cells/mm were randomized 1:1 to ABC + 3TC administered twice daily or EPZ administered once daily.

RESULTS

At baseline, median time on ABC and 3TC administered twice daily was 22 months, and median CD4 count and HIV-1 RNA level were 554 cells/mm and <50 copies/mL, respectively. EPZ administered once daily was established as not inferior to ABC + 3TC administered twice daily based on the proportion of nonvirologic failures (confirmed HIV-1 RNA level > or =1265 copies/mL; 90% confidence interval: -3.4 to 6.4; (intent to treat [ITT]: missing [M] = failure [F]). Proportions with an HIV-1 RNA level <50 copies/mL were 81% of those taking EPZ once daily and 82% of those taking ABC + 3TC twice daily at week 48 (ITT: M = F). Virologic failure was rare (2 patients taking the once-daily regimen, 4 patients taking the twice-daily regimen). There was a low incidence of grade 2 through 4 adverse events (AEs) and no drug-related serious AEs or hypersensitivity reactions.

CONCLUSIONS

EPZ administered once daily was established as not inferior to ABC + 3TC administered twice daily in a regimen containing an NNRTI or a PI over 48 weeks. A dual-nucleoside backbone of ABC and 3TC administered once or twice daily is effective, durable, and well tolerated.

Induction With Abacavir/Lamivudine/Zidovudine Plus Efavirenz for 48 Weeks Followed by 48-Week Maintenance With Abacavir/Lamivudine/Zidovudine Alone in Antiretroviral-Naive HIV-1-Infected Patients

BACKGROUND

The ESS40013 study tested 4-drug induction followed by 3-drug maintenance as initial antiretroviral therapy (ART) to reduce HIV RNA rapidly and then to simplify to an effective yet more convenient and tolerable regimen.

METHODS

Four hundred forty-eight antiretroviral-naive adults were treated with abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) and efavirenz (EFV) for the 48-week induction phase. Two hundred eighty-two patients were randomized in a 1:1 ratio to continue ABC/3TC/ZDV+EFV or to simplify to ABC/3TC/ZDV for the 48-week maintenance phase.

RESULTS

The baseline median HIV RNA level and CD4 cell count were 5.08 log10 copies/mL (56%>or=100,000 copies/mL) and 210 cells/mm (48% <200 cells/mm), respectively. No significant differences were noted between ABC/3TC/ZDV+EFV and ABC/3TC/ZDV for an HIV RNA level <50 copies/mL (79% vs. 77% [intent to treat (ITT), missing=failure]; P=0.697) or time to treatment failure (P=0.75) at week 96. Drug-related adverse events were more commonly reported for ABC/3TC/ZDV+EFV than for ABC/3TC/ZDV (15% vs. 6%). Improvements in total cholesterol, low-density lipoprotein cholesterol, and triglycerides were observed in the ABC/3TC/ZDV group. Virologic failure occurred in 22 patients during induction and in 24 patients (16 in ABC/3TC/ZDV group and 8 in ABC/3TC/ZDV+EFV group; P=0.134) during maintenance. A greater proportion of patients receiving ABC/3TC/ZDV than ABC/3TC/ZDV+EFV reported perfect adherence at week 96 (88.8% vs. 79.6%; P=0.057).

CONCLUSIONS

After induction with ABC/3TC/ZDV+EFV, simplification to ABC/3TC/ZDV alone maintained virologic control and immunologic response, reduced fasting lipids and ART-associated adverse events, and improved adherence.

Genotypic and phenotypic cross-resistance patterns to lopinavir and amprenavir in protease inhibitor-experienced patients with HIV viremia

Genotypic correlates of reduced phenotypic susceptibility to amprenavir (APV) and lopinavir (LPV) were examined in 271 HIV isolates from 207 protease inhibitor (PI)-experienced subjects. All samples were from LPV-naive subjects; two were from APV-experienced subjects. Using a fold resistance (FR) of <2.5, 179 (66%) were APV susceptible. Using FRs of <2.5 and <10, 107 (39%) and 194 (72%), respectively, were LPV susceptible. The I84V mutation was the strongest APV resistance marker in PI-experienced subjects in both univariate and multivariate analyses, with an increased relative incidence (RI) of 6.9 with >2.5 FR. Mutations L10I (RI, 1.7), M46I (RI, 2.3), and L90M (RI, 1.9, but 65% linked with the I84V) were associated with decreased APV susceptibility in the univariate analysis (p < 0.001). Mutations L10I, G48V, I54T, I54V, and V82A were significantly associated with decreased LPV susceptibility (p < 0.001 for each) and had increased RIs of 2.2, 4.4, 13, 4.6, and 3.2, respectively. Decreased susceptibility to LPV (FR, >or=10) was significantly associated with prior exposure to the following PIs: ritonavir (RTV) (p < 0.001), saquinavir (SQV) (p < 0.001), nelfinavir (NFV) (p = 0.008), and indinavir (IDV) (p = 0.028). Decreased APV susceptibility (FR, >or=2.5) was significantly associated with prior exposure to RTV (p = 0.009), NFV (p = 0.003), and IDV (p = 0.021) but not with prior SQV (p = 0.103). These results suggest that APV and LPV have different cross-resistance mutation patterns that may help determine choice of PI therapy after therapy failure.

Thymidine-analog and multi-nucleoside resistance mutations are observed in both zidovudine-naive and zidovudine-experienced subjects with viremia after treatment with stavudine-containing regimens

OBJECTIVE

The type and frequency of mutations in the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase coding region observed in virus from antiretroviral therapy (ART)-experienced, zidovudine (ZDV)-naive subjects receiving stavudine (d4T)-based therapies were compared with mutations observed in virus from ART-experienced subjects with previous ZDV exposure.

METHODS

Plasma HIV-1 RNA was isolated from 67 ART-experienced subjects. Reverse transcriptase mutations were assessed by sequencing polymerase chain reaction products.

RESULTS

Thirty-four subjects (51%) were ZDV-experienced (Z(exp)) and 33 (49%) were ZDV-naive and d4T-experienced (d(exp)Z(naive)). Human immunodeficiency virus type 1 from 16 of 33 (48%) d(exp)Z(naive) subjects and from 16 of 34 (47%) Z(exp) subjects had thymidine analog mutations (TAMs). Multi-nucleoside resistance (MNR) mutations were observed in virus from 5 of 33 (15%) d(exp)Z(naive) subjects and 3 of 34 (9%) Z(exp) subjects. At least one TAM or MNR mutation was identified in 18 of 33 (55%) of the former and in 19 of 34 (56%) of the latter group.

CONCLUSIONS

These results confirm recent reports that TAMs and MNR mutations can arise in subjects receiving d4T-based therapy who are naive with respect to ZDV.

Viral genetic heterogeneity in HIV-1-infected individuals is associated with increasing use of HAART and higher viremia

OBJECTIVE

To assess the correlation between the outgrowth of mutant viruses (viral genetic heterogeneity), highly active antiretroviral therapy (HAART), and plasma HIV-1 RNA in a population-based observational cohort study.

DESIGN

The study population consisted of 42 HIV-1-infected individuals receiving at least two nucleotide reverse transcriptase (RT) inhibitors and one or more protease inhibitors at study entry. There were no restrictions on antiretroviral therapy after enrollment.

METHODS

Plasma samples were obtained from subjects at baseline, at therapy changes, and at quarterly intervals for quantitation of HIV-1 RNA levels and for sequence determination of the entire protease coding region and the first 235 codons of the reverse transcriptase coding region. Data were analyzed using the generalized estimating equation method for longitudinal data and using linear regression analysis.

RESULTS

With increased time on HAART there were significant increases in the number of total HIV-1 mutations in the regions sequenced (P = 0.010). There were significant correlations between the increases in the plasma HIV-1 RNA levels and the numbers of total mutations and reverse transcriptase mutations (P = 0.007 and 0.021, respectively).

CONCLUSIONS

The number of HIV-1 mutations increased over time. Failure of HAART in this study population was correlated with outgrowth of virus with numerous mutations in the reverse transcriptase and protease coding regions. Phenotypic results correlated with genotypic results, showing decreased susceptibility to antiretrovirals over time in the majority of this population during HAART. Both synonymous and non-synonymous mutations were observed, with a higher incidence of non-synonymous mutations occurring at codons associated with drug resistance.

Deletions in the beta3-beta4 hairpin loop of HIV-1 reverse transcriptase are observed in HIV-1 isolated from subjects during long-term antiretroviral therapy

OBJECTIVES

To examine the effect of in-frame deletions in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) on plasma viremia and phenotypic resistance to antiretroviral drugs.

STUDY DESIGN/METHODS

Plasma HIV-1 RNA was isolated from 168 antiretroviral therapy-experienced subjects for quantification of plasma viremia, RT sequence analysis, and phenotypic resistance assays.

RESULTS

Four patients were found to harbor HIV-1 strains possessing in-frame, 3-nucleotide deletions at RT codons 67, 69, and 70. In these subjects, phenotypic resistance and high plasma viremia were observed only in a background of multiple resistance mutations. A recombinant virus engineered with an in-frame deletion of RT codon 67 did not have increased resistance to nucleoside reverse transcriptase inhibitors (NRTIs).

CONCLUSIONS

Selection for deletions within the beta3-beta4 hairpin loop of the HIV-1 RT is an uncommon event most likely to occur in subjects with long-term antiretroviral experience. The codon 67 deletion does not appear to cause increased phenotypic resistance or increased viremia in the absence of concomitant RT mutations.

The reverse transcriptase codon 69 insertion is observed in nucleoside reverse transcriptase inhibitor-experienced HIV-1-infected individuals, including those without prior or concurrent zidovudine therapy

OBJECTIVES

This study was undertaken to examine 6-bp insertions following codon 69 in the reverse transcriptase (RT) coding region of human immunodeficiency virus type 1 (HIV-1) mutations in terms of incidence, presence of additional RT mutations, phenotypic drug resistance, HIV-1 RNA levels, and antiretroviral treatment history.

STUDY DESIGN/METHODS

A retrospective study of 121 nucleoside reverse transcriptase inhibitor (NRTI)-experienced subjects infected with HIV-1 was performed. Methods included quantitation of HIV-1 RNA levels, genotypic analyses of the RT and protease coding regions, and determination of phenotypic drug resistance.

RESULTS

A 6-bp insertion following RT codon 69 was observed in viral isolates from 4 subjects. Two subjects had a history of zidovudine (ZDV)-based therapy, and two subjects had a history of stavudine (D4T)-based therapy without prior exposure to ZDV. The T69S mutation and the 6-bp insertion following RT codon 69 were the only RT mutations observed in the 2 subjects with a history of D4T-based therapy.

CONCLUSIONS

Six-basepair insertions occurred in virus from 4 of 121 (3%) NRTI-experienced subjects, including those without prior ZDV treatment, and was observed in the absence of the T215Y mutation. There was no apparent correlation between insertion incidence and HIV-1 viremia.

Nursing implications of immunosuppression in transplantation

The numbers and survival rates of patients undergoing solid organ transplantation have increased over the past decade. The use of immunosuppressive drugs has contributed greatly to the success of transplantation. Drugs such as cyclosporine, steroids, azathioprine, ATG/ALG, OKT3, and new drugs under investigation such as FK506 are being used on a daily basis by nurses who care for organ transplant patients. This article reviews these medications and the implications for nurses administering these drugs.