Severe anemia as a newly recognized side-effect caused by lamivudine

A case series of emtricitabine-induced pure red cell aplasia

Background

Anaemia is common in patients with retroviral disease. New or worsening anaemia after initiation of antiretroviral (ARV) treatment has a broad differential diagnosis.

Objectives

We describe six patients who developed transfusion-dependent anaemia on first-line therapy (tenofovir, emtricitabine and efavirenz) and, by exclusion, implicated emtricitabine in the aetiology of the anaemia.

Method

We conducted a retrospective chart review of patients seen at the Infectious Diseases specialist clinic at King Edward VIII Hospital in KwaZulu-Natal between 2014 and 2016. We focused on patients with isolated, refractory and transfusion-dependent anaemia occurring after initiation of ARVs, in whom bone marrow biopsies were consistent with pure red cell aplasia (PRCA) without an identifiable secondary cause.

Results

All the patients were female, with a median (range) age and baseline CD4 cell count of 42.5 (23–61) years and 237 (83–329) cells/mm³, respectively. Before presenting with symptomatic anaemia, the duration on emtricitabine was 4.5 (2–8) months. At presentation, all patients had an HIV viral load of < 1000 copies/mL and a CD4 cell count of 314 (213–389) cells/mm³. The median time to recovery following the discontinuation of emtricitabine was 2 (1–4) months. After a median of 12 months, all patients were successfully rechallenged with emtricitabine and remained well for a follow-up period of 24 (7–36) months.

Conclusion

This study provides strong circumstantial evidence that emtricitabine plays an important role in the pathogenesis of reversible PRCA. The mechanisms through which emtricitabine induces PRCA remain unclear and require further study.

Emtricitabine-associated red cell aplasia

: Emtricitabine is structurally similar to lamivudine, which has been associated with red cell aplasia. We describe four patients with severe anaemia presenting soon after starting emtricitabine-containing antiretroviral therapy. Bone marrow biopsy in three patients confirmed red cell aplasia. Anaemia resolved after emtricitabine withdrawal in three patients, one patient died, and anaemia recurred on rechallenge in one patient whose anaemia persisted on lamivudine, resolving when this was stopped, suggesting a possible cross-reaction between lamivudine and emtricitabine.

Pure red cell aplasia induced by lamivudine without the influence of zidovudine in a patient infected with human immunodeficiency virus

We herein report the case of a patient with human immunodeficiency virus infection and acquired immune deficiency syndrome who was diagnosed with drug-induced pure red cell aplasia consequent to lamivudine treatment. The patient was admitted to our hospital for treatment of increasing shortness of breath following physical effort. Upon admission, routine blood tests revealed a hemoglobin level of 7.6 g/dL and a hematocrit proportion of 21.2%, with normal leukocyte and platelet counts. After stopping the lamivudine treatment, the patient's hemoglobin concentration and hematocrit level returned to normal. A bone marrow examination showed an exclusive reduction in erythrocyte formation. This case indicates that lamivudine can induce severe anemia without the influence of zidovudine.

Increased risk of severe infant anemia after exposure to maternal HAART, Botswana

BACKGROUND

Maternal highly-active antiretroviral therapy (HAART) reduces mother-to-child HIV transmission but may increase the risk for infant anemia.

METHODS

The incidence of first severe anemia (grade 3 or 4, Division of AIDS 2004 Toxicity Table) was assessed among HIV-uninfected infants in the Mashi and Mma Bana mother-to-child HIV transmission prevention trials in Botswana. Severe anemia rates were compared between 3 groups: infants exposed to maternal HAART in utero and during breastfeeding (BF) and 1 month of postnatal zidovudine (ZDV) (HAART-BF); infants exposed to maternal ZDV in utero, 6 months of postnatal ZDV, and BF (ZDV-BF); and infants exposed to maternal ZDV in utero, 1 month of postnatal ZDV, and formula-feeding (ZDV-FF).

RESULTS

A total of 1719 infants were analyzed-691 HAART-BF, 503 ZDV-BF, and 525 ZDV-FF. Severe anemia was detected in 118 infants (7.4%). By 6 months, 12.5% of HAART-BF infants experienced severe anemia, compared with 5.3% of ZDV-BF (P < 0.001) and 2.5% of ZDV-FF infants (P < 0.001). In adjusted analysis, HAART-BF infants were at greater risk of severe anemia than ZDV-BF or ZDV-FF infants (adjusted odds ratios 2.6 and 5.8, respectively; P < 0.001). Most anemias were asymptomatic and improved with iron/multivitamin supplementation and cessation of ZDV exposure. However, 11 infants (0.6% of all infants) required transfusion for symptomatic anemia. Microcytosis and hypochromia were common among infants with severe anemia.

CONCLUSIONS

Exposure to maternal HAART starting in utero was associated with severe infant anemia. Confirmation of this finding and possible strategies to mitigate hematologic toxicity warrant further study.

Three generic nevirapine-based antiretroviral treatments in Chinese HIV/AIDS patients: multicentric observation cohort

Background

The purpose of this study was to evaluate the efficacy and safety of three nevirapine-based antiretroviral treatments for adult antiretroviral-naïve Chinese patients with HIV-1 infection.

Methodology

This was a prospective, multicenter study. 198 antiretroviral-naïve HIV-1 positive subjects with CD4 lymphocyte counts between 100/ul and 350/ul and plasma HIV-1 RNA levels more than 500 copies/ml were randomized to start three NVP-based antiretroviral treatments: group A, NVP+AZT+ddI; group B, NVP+3TC+d4T; group C, NVP+AZT+3TC. Viral responses, immunologic responses, adverse events and drug resistence were monitored at baseline and the end of week 4, 12, 24, 36, 52. Viralogical response and immunological response were also comparaed in different strata of baseline CD4 T lymphocyte counts and plasma HIV-1 RNA concentrations. At baseline, the plasma HIV-1 RNA was 4.44±0.68, 4.52±0.71 and 4.41±0.63 lg copies/ml in group A, B and C respectively (p = 0.628). At the end of the study, the plasma viral load reached 2.54±1.11, 1.89±0.46 and 1.92±0.58 lg copies/ml in group A, B and C respectively (p<0.001). At week 52, suppression of plasma HIV-1 RNA to less than 50 copies/ml was achieved in more patients in group B and C than in group A (68.2%, 69% vs. 39.7%; p<0.001). In planned subgroup analyses, the decrease of viral response rate was seen in group A when CD4 cell count >200/ul (subgroup H). But in subgroup L, viral response rate of three groups has no significant statistic difference. There were no statistically significant differences among three groups in immunological response wthin any of the CD4 or pVL strata. 3 out of 193 patients with available genotype at baseline showed primary drug resistant. Of 26 patients with virologic failure, 17 patients showed secondary drug resistant, 16 subjects in group A and 1 subject in group B. Logistic regression analysis indicated that presence of hepatotoxicity was associated with HCV-Ab positive (OR = 2.096, 95%CI: 1.106–3.973, P = 0.023) and higher CD4 baseline (CD4 count >250/ul)(OR = 2.096, 95%CI: 1.07–4.107, P = 0.031).

Conclusion

Our findings strongly support the use of 3TC+d4T and 3TC+AZT as the nucleoside analogue combination in NVP-based antiretroviral therapy. The regimen of AZT+ddI+NVP produced poor virological response especially in the stratum of CD4 count more than 200/ul. More patients showed secondary drug resistant in this arm too. Patients with HCV-Ab+ and CD4 count >250/ul appear to have significantly high risk of hepatoxicity.

Trial Registration

ClinicalTrials.gov NCT00618176

Effects of lamivudine therapy on the glucose metabolism in children with chronic hepatitis B: first year follow-up results

BACKGROUND AND AIM

Although the most common major toxicity of lamivudine has been pancreatitis, there is no report investigating possible impaired pancreatic functions, including glucose intolerance due to lamivudine therapy. The aim of this study was to evaluate the effects of lamivudine on the glucose metabolism in children.

METHOD

Twenty-three children were included: eight patients were treated with lamivudine, others with both lamivudine and interferon-alpha. An oral glucose tolerance test (OGTT) was performed before the treatment, and after 6 and 12 months.

RESULTS

After 6 and 12 months of the treatment four (18.4%) and eight (34.8%) patients had impaired OGTT, respectively. We did not find any relationship between impaired OGTT and age, gender, elevated amylase, abdominal pain and the mode of therapy (P>0.05). While mean glucose value after 2 h was higher than that of baseline, mean insulin concentrations and area under the curve values were not different (P<0.0001, P>0.05, and P>0.05, respectively).

CONCLUSION

This is the first report demonstrating that lamivudine may impair the OGTT. Since at least 8.7% of our patients had persistently impaired OGTTs during the first year of the therapy, it may be reasonable to screen children before lamivudine therapy is started.

Structure modifications of 6-aminoquinolones with potent anti-HIV activity

We have recently discovered that 6-aminoquinolone derivatives could be valid leads for the development of new anti-HIV agents because of their new and diversified mode of action. In fact, studies carried out on the lead WM5 showed that this derivative is able to inhibit the Tat-mediated long terminal repeat driven transcription, an essential step in the HIV-1 replication cycle. Thus, starting from lead WM5, we performed the design and synthesis of an enlarged series of 6-aminoquinolones, which permitted some very potent anti-HIV 6-amino derivatives to be obtained and the structure-activity relationship to be delineated. Some derivatives, 26c, 26e, 26i, and 26j, proved to be highly effective in inhibiting HIV replication at 50% inhibitory concentration in the range of 0.0087-0.7 microg/mL in MT-4, PBMCs and CEM cell lines coupled with positive selectivity indexes that reach values higher than 1000 on CEM cell lines for compounds 26e and 26i. Time-of-addition experiments clearly confirm that the new, potent 6-aminoquinolones interact at a postintegration step in the replication cycle of HIV.

Generation of predictive pharmacophore models for CCR5 antagonists: study with piperidine- and piperazine-based compounds as a new class of HIV-1 entry inhibitors

Predictive pharmacophore models were developed for a large series of piperidine- and piperazine-based CCR5 antagonists as anti-HIV-1 agents reported by Schering-Plough Research Institute in recent years. The pharmacophore models were generated using a training set consisting of 25 carefully selected antagonists based on well documented criteria. The activity spread, expressed in K(i), of training set molecules was from 0.1 to 1300 nM. The most predictive pharmacophore model (hypothesis 1), consisting of five features, namely, two hydrogen bond acceptors and three hydrophobic, had a correlation (r) of 0.920 and a root mean square of 0.879, and the cost difference between null cost and fixed cost was 44.46 bits. The model was cross-validated by randomizing the data using the CatScramble technique. The results confirmed that the pharmacophore models generated from the test set were not due to chance correlation. The best model (hypothesis 1) was validated using test set molecules (total of 78) and performed well in classifying active and inactive molecules correctly. The model was further validated by mapping onto it a diverse set of six CCR5 antagonists identified by five different pharmaceutical companies. The best model correctly predicted these compounds as being highly active. These multiple validation approaches provide confidence in the utility of the predictive pharmacophore model developed in this study as a 3D query tool in virtual screening to retrieve new chemical entities as potent CCR5 antagonists. The model can also be used in predicting biological activities of compounds prior to undertaking their costly synthesis.

Is AZT/3TC therapy effective against FIV infection or immunopathogenesis?

In vitro and in vivo prophylactic and therapeutic efficacy of AZT/3TC treatment was evaluated against feline immunodeficiency virus (FIV) infection. In vitro studies utilized FIV-infected peripheral blood mononuclear cells (PBMCs) or FIV-infected T-cell lines treated with AZT (azidothymidine) alone, 3TC alone, or AZT/3TC combination and tested for anti-FIV activity and drug toxicity. AZT/3TC combination had additive to synergistic anti-FIV activities in primary PBMC but not in chronically infected cell lines. In vivo studies consisted of four treatment groups (n=15) of SPF cats receiving AZT/3TC combination (5-75 mg/kg/drug PO BID for 8 or 11 weeks) and one control group (n=9) receiving oral placebo. Group I (n=6, 150 mg/kg/drug/day) was treated starting 3 days pre-FIV inoculation, whereas Group II (n=3, 150 mg/kg/drug/day) and Group III (n=3, 100 mg/kg/drug/day) treatments were simultaneous with FIV inoculation. Group IV treatment (n=3, 100 mg/kg/drug/day) was initiated 2 weeks post-FIV inoculation. All cats were monitored for drug toxicity and FIV infection. Eighty-three percent of cats in Group I and 33% of cats in Groups II and III were completely protected from FIV infection. A significant delay in infection and antibody seroconversion was observed in all unprotected cats from Groups I, II and III. Group IV cats had only a slight delay in FIV antibody seroconversion. Adverse drug reactions (anemia and neutropenia) were observed at high doses (100-150 mg/kg/drug/day) were reversible upon lowering the dose (20 mg/kg/drug/day). In contrast, AZT/3TC treatment had no anti-FIV activity in chronically infected cats. Furthermore, severe clinical symptoms caused by adverse drug reactions were observed in some of these cats. Overall, AZT/3TC treatment is effective for prophylaxis but not for therapeutic use in chronically FIV-infected cats.