Results from a Joined Prospective Study to Evaluate the Sensitivity of the In Vivo Dog QT Assay in Line with the ICH E14/S7B Q&A Best Practices.

The ICH E14/S7B Q&As highlighted the need for best practices concerning the design, execution, analysis, interpretation, and reporting of the in vivo non-rodent QT assay as a component of the integrated risk assessment to potentially support a TQT waiver or substitute. We conducted a dog telemetry study to assess the effects on QTc of six reference compounds (five positive and one negative) previously evaluated by Darpo et al. (2015) in humans. The sensitivity of the assay to detect QTc increases was determined, and exposure-response analysis was performed, as done in clinical practice. By-timepoint analysis showed QTc prolongation induced by moxifloxacin, dofetilide, dolasetron, ondansetron, and quinine within human relevant plasma exposures ranges. Moreover, a hysteresis was observed for quinine. As expected, levocetirizine showed no statistically significant effect on QTc across a range of exposure, well exceeding the therapeutic Cmax. Power analyses confirmed the study ability to detect statistically significant QTc changes of less than 10 milliseconds with 80% probability, even with a sample size as low as n = 4 animals. Finally, concentration-QTc modeling enabled to predict the minimal plasma concentration needed to detect a 10 milliseconds QTc prolongation, including for quinine. The comparison with clinical available data supported the relevance of dogs under these experimental conditions as a robust translational predictor of drug-induced QTc prolongation in humans as a key pillar of the integrated risk assessment.

Pharmacokinetics, safety, and tolerability of the 2- and 3-direct-acting antiviral combination of AL-335, odalasvir, and simeprevir in healthy subjects.

This Phase I, open-label, two-group, fixed-sequence study evaluated the pharmacokinetics and safety of AL-335, odalasvir, and simeprevir in healthy subjects. Group 1 (n = 16) received AL-335 800 mg once daily (QD) (days 1-3, 11-13, and 21-23), simeprevir 150 mg QD (days 4-23), and odalasvir 150 mg (day 14) followed by 50 mg QD (days 15-23). Group 2 (n = 16) received the same AL-335 regimen as in Group 1 plus odalasvir 150 mg (day 4) followed by 50 mg QD (days 5-23) and simeprevir 150 mg QD (days 14-23). Blood samples were collected to determine plasma concentrations of AL-335 (prodrug) and its metabolites, ALS-022399 (monophosphate precursor) and ALS-022227 (parent nucleoside), odalasvir, and simeprevir. Thirty-two subjects were enrolled. Odalasvir and simeprevir given alone, or in combination, increased AL-335 area under plasma concentration-time curve over 24 hours (AUC 0-24 h) 3-, 4-, and 7- to 8-fold, respectively; ALS-022399 AUC 0-24 h increased 2-, 2-, and 3-fold, respectively. Simeprevir had no effect on ALS-022227 AUC 0-24 h, whereas odalasvir with/without simeprevir increased ALS-022227 AUC 0-24 h 1.5-fold. AL-335 had no effect on odalasvir or simeprevir pharmacokinetics. Odalasvir and simeprevir AUC 0-24 h increased 1.5- to 2-fold for both drugs when coadministered irrespective of AL-335 coadministration. Study medications were well tolerated with no serious adverse events. One subject prematurely discontinued study drugs (unrelated event). This study defined the preliminary pharmacokinetic and safety profiles of the combination of AL-335, odalasvir, and simeprevir in healthy subjects. These data support the further evaluation of this combination for the treatment of chronic hepatitis C virus infection.

Predictive values of the human immunodeficiency virus phenotype and genotype and of amprenavir and lopinavir inhibitory quotients in heavily pretreated patients on a ritonavir-boosted dual-protease-inhibitor regimen.

The inhibitory quotient (IQ) of human immunodeficiency virus (HIV) protease inhibitors (PIs), which is the ratio of drug concentration to viral susceptibility, is considered to be predictive of the virological response. We used several approaches to calculate the IQs of amprenavir and lopinavir in a subset of heavily pretreated patients participating in the French National Agency for AIDS Research (ANRS) 104 trial and then compared their potentials for predicting changes in the plasma HIV RNA level. Thirty-seven patients were randomly assigned to receive either amprenavir (600 mg twice a day [BID]) or lopinavir (400 mg BID) plus ritonavir (100 or 200 mg BID) for 2 weeks before combining the two PIs. The 90% inhibitory concentration (IC(90)) was measured using a recombinant assay without or with additional human serum (IC(90+serum)). Total and unbound PI concentrations in plasma were measured. Univariate linear regression was used to estimate the relation between the change in viral load and the IC(90) or IQ values. The amprenavir phenotypic IQ values were very similar when measured with the standard and protein binding-adjusted IC(90)s. No relationship was found between the viral load decline and the lopinavir IQ. During combination therapy, the amprenavir and lopinavir genotypic IQ values were predictive of the viral response at week 6 (P = 0.03). The number of protease mutations (< 5 or > or = 5) was related to the virological response throughout the study. These findings suggest that the combined genotypic IQ and the number of protease mutations are the best predictors of virological response. High amprenavir and lopinavir concentrations in these patients might explain why plasma concentrations and the phenotypic IQ have poor predictive value.

Salvage therapy with amprenavir, lopinavir and ritonavir is durably potent in HIV-infected patients in virological failure: 1-year results.

We report the results of the extended follow-up at one year of a randomized trial evaluating the virological efficacy of a salvage therapy combining lopinavir and amprenavir with either 200 or 400 mg/day ritonavir, along with optimized nucleoside reverse transcriptase inhibitors, in patients carrying multidrug-resistant isolates. The combination of amprenavir, lopinavir and ritonavir (400 mg/day) is durably potent, yielding a sustained virological response (HIV RNA < 50 copies) in 39% of cases.

Long-term outcome of AIDS-associated cryptococcosis in the era of combination antiretroviral therapy.

BACKGROUND: Immune restoration following combination antiretroviral therapy (cART) questions the maintenance of prophylaxis among HIV-infected patients with cryptococcosis. OBJECTIVE: To describe the long-term outcome after the diagnosis of cryptococcosis at the cART era. DESIGN: Multicentre cohort of patients with a diagnosis of cryptococcosis between 1996 and 2000, follow-up until December 2002. Comparison with a historical cohort (1990-1994) for survival. SETTING: Eighty-four French AIDS clinical centres. PATIENTS: Two-hundred and forty HIV-infected adult patients at the cART era and 149 at the pre-cART era experiencing a first episode of culture-confirmed cryptococcosis. RESULTS: In the cART era, 82/189 patients surviving more than 3 months after initiation of antifungal therapy had their maintenance therapy interrupted with a subsequent median follow-up of 19 months. Their relapse rate per 100 person-years was 0.9 [95% confidence interval (CI),0.0-2.0]. When considering the whole cART cohort, probability of reaching negative serum cryptococcal antigen was 71% after 48 months of follow-up. A CD4 cell count < 100/microl [relative risk (RR), 5.5; 95% CI, 1.3-22.2], antifungal therapy < 3 months over the past 6 months [RR, 5.0; 95% CI, 1.1-22.3] and serum cryptococcal antigen titre > or = 1/512 [RR, 3.5; 95% CI, 1.1-10.8] were associated with a higher rate of cryptococcosis relapse. The mortality rate per 100 person-years was 15.3 [95% CI,12.2-18.4] in the cART era versus 63.8 [95% CI,53.0-74.9] in the pre-cART era although early mortality did not differ between the two periods. CONCLUSION: Overall survival after cryptococcosis has dramatically improved at the cART era. Immune restoration and low serum cryptococcal antigen titres are associated with lower cryptococcosis relapse rates.

Low genetic barrier to large increases in HIV-1 cross-resistance to protease inhibitors during salvage therapy.

HIV-1 resistance to protease inhibitors (PIs) is characterized by extensive cross-resistance within this drug class. Some PIs, however, appear less affected by cross-resistance and are often prescribed in salvage therapy regimens for patients who have failed previous PI treatment. To examine the capacity of HIV-1 to adapt to these treatment changes, we have followed the evolution of HIV-1 protease genotypes and phenotypes in 21 protease-inhibitor-experienced patients in whom 26 weeks of an aggressive salvage regimen associating lopinavir, amprenavir and ritonavir failed to suppress viral replication. Baseline genotypes exhibited a median of seven resistance mutations in the protease. After 26 weeks of treatment, changes in protease genotypes were seen in 13/21 patients. The evolution of these protease genotypes was rapid, with more than one-third of the changes occurring during the first 6 weeks. Although the mean number of additional mutations was small (2.15 new mutations at week 26) these mutations were sufficient to promote remarkable changes in resistance phenotype. In several patients, some of the new mutations were found to exist before salvage treatment as part of minority quasi-species. Thus, in the face of the strong pharmacological pressure exerted by combinations of PIs to which it has never been exposed, and in spite of limited cross-resistance to these drugs before salvage therapy, HIV-1 can rapidly adapt its resistance genotype and phenotype at a minimal evolutionary cost.

Biases in observational studies of the effect of prenatal treatment for congenital toxoplasmosis.

The paper reviews methodological difficulties that arise when using observational studies to evaluate the effect of prenatal screening and treatment. The principle of each difficulty is described and then illustrated by a clinical example of toxoplasmosis in pregnancy and its consequences. Methods to deal with these difficulties are described. Given the limitations of existing observational studies and lack of randomised controlled trials, a systematic review of cohort studies offers the best approach for exploring potential biases.