[Severe lactic acidosis in HIV-infected patients treated with nucleosidic reverse transcriptase analogs: a report of 9 cases]

Severe Lactic Acidosis Due to Inappropriate Use of Biktarvy in a Patient With AIDS

Bictegravir-emtricitabine-tenofovir alafenamide is an approved medication for the treatment of acquired immunodeficiency syndrome (AIDS). This medication, also called Biktarvy, includes an integrase strand inhibitor combined with nucleoside reverse transcriptase inhibitors (NRTIs) to prevent viral DNA synthesis and lead to improvements in disease progression and mortality in patients with AIDS. A rare but previously documented adverse effect of NRTIs present in Biktarvy is lactic acidosis. NRTIs can cause lactic acidosis through mitochondrial impairment, as mitochondria depend on DNA polymerase gamma for replication. This enzyme is very similar to HIV's reverse transcriptase. Inhibition of mitochondrial production results in increased anaerobic metabolism and lactic acid production. We present a case where an inappropriately high dosage of Biktarvy in a patient with septic shock led to persistent lactic acidosis despite clinical improvement. After a thorough medication review, Biktarvy was temporarily held, and the lactic acidosis resolved. This clinical presentation stresses the importance of maintaining wide differentials for lactic acidosis and thorough medication reconciliation.

Blood lactate monitoring in critically ill patients: a systematic health technology assessment

OBJECTIVE

To decide whether the use of blood lactate monitoring in critical care practice is appropriate. We performed a systematic health technology assessment as blood lactate monitoring has been implemented widely but its clinical value in critically ill patients has never been evaluated properly.

DATA SOURCE

PubMed, other databases, and citation review.

STUDY SELECTION

We searched for lactate combined with critically ill patients as the target patient population. Two reviewers independently selected studies based on relevance for the following questions: Does lactate measurement: 1) perform well in a laboratory setting? 2) provide information in a number of clinical situations? 3) relate to metabolic acidosis? 4) increase workers' confidence? 5) alter therapeutic decisions? 6) result in benefit to patients? 7) result in similar benefits in your own setting? 8) result in benefits which are worth the extra costs?

DATA EXTRACTION AND SYNTHESIS

We concluded that blood lactate measurement in critically ill patients: 1) is accurate in terms of measurement technique but adequate understanding of the (an)aerobic etiology is required for its correct interpretation; 2) provides not only diagnostic but also important prognostic information; 3) should be measured directly instead of estimated from other acid-base variables; 4) has an unknown effect on healthcare workers' confidence; 5) can alter therapeutic decisions; 6) could potentially improve patient outcome when combined with a treatment algorithm to optimize oxygen delivery, but this has only been shown indirectly; 7) is likely to have similar benefits in critical care settings worldwide; and 8) has an unknown cost-effectiveness.

CONCLUSIONS

The use of blood lactate monitoring has a place in risk-stratification in critically ill patients, but it is unknown whether the routine use of lactate as a resuscitation end point improves outcome. This warrants randomized controlled studies on the efficacy of lactate-directed therapy.

Benefit of antiretroviral therapy on survival of human immunodeficiency virus-infected patients admitted to an intensive care unit

OBJECTIVE

To evaluate the impact of antiretroviral therapy (ART) and the prognostic factors for in-intensive care unit (ICU) and 6-month mortality in human immunodeficiency virus (HIV)-infected patients.

DESIGN

A retrospective cohort study was conducted in patients admitted to the ICU from 1996 through 2006. The follow-up period extended for 6 months after ICU admission.

SETTING

The ICU of a tertiary-care teaching hospital at the Universidade de São Paulo, Brazil.

PARTICIPANTS

A total of 278 HIV-infected patients admitted to the ICU were selected. We excluded ICU readmissions (37), ICU admissions who stayed less than 24 hours (44), and patients with unavailable medical charts (36).

OUTCOME MEASURE

In-ICU and 6-month mortality.

MAIN RESULTS

Multivariate logistic regression analysis and Cox proportional hazards models demonstrated that the variables associated with in-ICU and 6-month mortality were sepsis as the cause of admission (odds ratio [OR] = 3.16 [95% confidence interval [CI] 1.65-6.06]); hazards ratio [HR] = 1.37 [95% CI 1.01-1.88]), an Acute Physiology and Chronic Health Evaluation II score >19 [OR = 2.81 (95% CI 1.57-5.04); HR = 2.18 (95% CI 1.62-2.94)], mechanical ventilation during the first 24 hours [OR = 3.92 (95% CI 2.20-6.96); HR = 2.25 (95% CI 1.65-3.07)], and year of ICU admission [OR = 0.90 (95% CI 0.81-0.99); HR = 0.92 [95% CI 0.87-0.97)]. CD4 T-cell count <50 cells/mm(3) was only associated with ICU mortality [OR = 2.10 (95% CI 1.17-3.76)]. The use of ART in the ICU was negatively predictive of 6-month mortality in the Cox model [HR = 0.50 (95% CI 0.35-0.71)], especially if this therapy was introduced during the first 4 days of admission to the ICU [HR = 0.58 (95% CI 0.41-0.83)]. Regarding HIV-infected patients admitted to ICU without using ART, those who have started this treatment during ICU stay presented a better prognosis when time and potential confounding factors were adjusted for [HR 0.55 (95% CI 0.31-0.98)].

CONCLUSIONS

The ICU outcome of HIV-infected patients seems to be dependent not only on acute illness severity, but also on the administration of antiretroviral treatment.

[Mitochondrial cytopathies associated with HIV infection]

The tremendous progress achieved during the last few years with the use of highly active antiretroviral therapy in suppressing HIV replication together with improvements in immunity have been tempered by a growing number of new adverse effects. Mitochondrial toxicity is one aspect of these long-term toxicities of antiretroviral drugs, with the role of nucleoside analogs particularly underlined. Some cases of impaired mitochondrial function have been clearly identified, such as pancreatitis due to didanosine, neuropathy due to zalcitabine, myopathy due to zidovudine, and lactic acidosis due to stavudine. These mitochondrial toxicities can affect several organs, presenting different patterns of symptoms: from asymptomatic to states with few symptoms despite huge metabolic abnormalities whose prognosis is immediately life-threatening. Beyond the inhibition of DNA polymerase gamma using nucleoside analogs, responsible for decreasing mitochondrial DNA in certain targeted organs, it appears that several physiopathologic mechanisms interact to explain this observed toxicity, HIV itself plays a role, and the underlying genetic pool needs to be better identified. Such cases mean that, it is imperative to avoid cumulated toxicities caused by associated treatments. With serious cases, or persistent symptoms despite discontinuing the nucleoside analogs responsible for such toxicity, one must propose vitamins, mitochondrial co-factors, or anti-oxidants. However, the future lies in the use of potent, less toxic nucleoside analogs, and in developing compounds belonging to other classes of antiretrovirals.

Muscle and Liver Lactate Metabolism in Haart-Treated and Naive HIV-Infected Patients: The Mitovir Study

Objective

To assess the impact of nucleoside analogue reverse transcriptase inhibitor (NRTI) combination therapy on muscle and liver lactate metabolism in HIV-infected patients.

Methods

This cross-sectional study involved HIV-infected patients who were either antiretroviral-naive (Group 1) or were receiving either a stable triple-drug combination including at least one d-drug (zidovudine, zalcitabine, stavudine, didanosine; Group 2) or a backbone of abacavir and lamivudine (Group 3). Lactataemia was measured at rest. Muscle lactate metabolism was assessed during a standardized exercise test and liver lactate metabolism during intravenous lactate infusion. Mitochondrial DNA was quantified in peripheral blood mononuclear cells.

Results

A total of 65 patients were enrolled (16, 31 and 18 patients in Group 1, Group 2 and Group 3, respectively). None of the patients had symptoms of hyperlactataemia. Patients in Group 3 had received d-drugs for a median of seven years before switching to abacavir and lamivudine. Median baseline lactataemia, although within the normal range, was significantly higher in both treatment groups than in the naive patients (Group 2: 1.4, Group 3: 1.5, and Group 1: 1.0 mmol/l, P=0.005). Muscle lactate clearance was significantly lower in both treatment groups than in naive patients (Group 2: 1.6, Group 3: 1.8, and Group 1: 2.1, P=0.01). Lactate liver metabolism and mitochondrial DNA levels did not differ among the three groups.

Conclusions

In HIV-infected patients without symptomatic hyperlactataemia, all NRTI-containing HAART regimens appear to cause muscle mitochondrial damage but to spare the liver. Absence of difference between Group 2 and Group 3 raises questions about the potential reversibility of muscle mitochondrial dysfunction, and/or the ability of abacavir and lamivudine to induce such mitochondrial damage.

The Role of Hepatitis C Virus (HCV) in Mitochondrial Dna Damage in HIV/HCV-Coinfected Individuals

Oxidative stress accompanying hepatitis C virus (HCV) infection seems to result in mitochondrial (mt) dysfunction. In HIV/HCV-coinfected individuals, HCV-related mt damage could be further enhanced and clinical manifestations of mt damage may appear, particularly following exposure to some antiretroviral drugs. Furthermore, when HCV medications are used together with certain antiretrovirals, the risk of developing mt adverse events may be particularly frequent, such as development of pancreatitis when ribavirin and didanosine are coadministered. The management of HIV/HCV-coinfected individuals needs to consider the high risk of mitochondria-associated toxicities in this population, which may significantly influence treatment decisions and therapeutic modalities.

Peginterferon alfa-2b plus ribavirin compared with interferon alfa-2b plus ribavirin for treatment of HIV/HCV co-infected patients

BACKGROUND

Current therapies for chronic hepatitis C virus (HCV) in HIV co-infected patients have a low success rate and are poorly tolerated. We have evaluated the efficacy and safety of interferon alfa-2b (IFN) + ribavirin (RBV) versus pegylated interferon alfa-2b (PEG-INF) + RBV.

METHODS

Randomized, single-centre, open-label clinical trial including patients with: detectable HCV-RNA, alanine aminotransferase > 1.5-fold upper limit of normal, abnormal liver histology, CD4 cell count > 250 x 10/l and HIV RNA < 10 000 copies/ml. Patients were assigned to INF (3 x 10 units three times/week) or PEG-IFN (100-150 microg/week) plus RBV (800-1200 mg/day). Duration of treatment was 48 weeks (only 24 weeks for HCV genotypes 2 or 3 and baseline HCV RNA < 800 000 IU/ml). The primary endpoint was a sustained virological response (SVR).

RESULTS

Ninety-five patients were randomized (43 INF + RBV, 52 PEG-INF + RBV), 68% males, 82% injecting drug users; 63% genotypes 1 or 4 and 36% genotypes 2 or 3; 62% fibrosis index grade >/=2 and 30% bridging fibrosis/cirrhosis. SVR was significantly higher in the PEG-INF + RBV arm, 44% versus 21% (intent to treat; P = 0.017). Among patients with genotypes 1 or 4, SVR were 38% versus 7% (P = 0.007) and 53% versus 47% (P = 0.730) for genotypes 2 or 3. CD4 cell count but not its percentage dropped in both arms and HIV RNA viral load did not change from baseline. Side effects were very frequent in both arms leading to treatment discontinuation in 14 patients without statistical differences between arms (P = 0.565).

CONCLUSION

PEG-INF + RBV was significantly more effective than INF + RBV for the treatment of chronic hepatitis C in HIV co-infected patients, mainly of genotype 1 or 4.

The cellular pharmacology of nucleoside- and nucleotide-analogue reverse-transcriptase inhibitors and its relationship to clinical toxicities

Nucleoside- and nucleotide-analogue reverse-transcriptase inhibitors (NRTIs) require intracellular phosphorylation for anti-human immunodeficiency virus (HIV) activity and toxicity. Long-term toxicities associated with NRTIs may be related to overactivation of this process. In vitro experiments have shown increased rates of NRTI and endogenous nucleoside phosphorylation to be associated with cellular activation. Patients with advanced HIV disease often have overexpression of cytokines, which corresponds to an elevated cellular activation state. These patients also have higher rates of NRTI phosphorylation and NRTI toxicity, suggesting an interaction between a proinflammatory biological state, NRTI phosphorylation, and toxicity. Studies suggest that women may have higher rates of NRTI phosphorylation than do men, as well as increased risk for NRTI-induced toxicity. Future research is needed to understand the NRTI activation process and improve the long-term toxicity profile of NRTIs. Such research should include comparisons of NRTI phosphorylation according to sex and cellular activation state (i.e., elevated vs. low).