Safety, tolerability, and pharmacokinetics of casimersen in patients with Duchenne muscular dystrophy amenable to exon 45 skipping: A randomized, double-blind, placebo-controlled, dose-titration trial.

INTRODUCTION/AIMS: Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene resulting in the absence of dystrophin. Casimersen is a phosphorodiamidate morpholino oligomer designed to bypass frameshift DMD mutations and produce internally truncated, yet functional, dystrophin protein in patients amenable to exon 45 skipping. Our primary study objective was to evaluate safety and tolerability of casimersen; the secondary objective was to characterize the plasma pharmacokinetics. METHODS: This multicenter, phase 1/2 trial enrolled 12 participants (aged 7-21 years, who had limited ambulation or were nonambulatory) and comprised a 12-week, double-blind dose titration, then an open-label extension for up to 132 weeks. During dose titration, participants were randomized 2:1 to weekly casimersen infusions at escalating doses of 4, 10, 20, and 30 mg/kg (≥2 weeks per dose), or placebo. RESULTS: Participants received casimersen for a mean 139.6 weeks. Treatment-emergent adverse events (TEAEs) occurred in all casimersen- and placebo-treated participants and were mostly mild (over 91.4%) and unrelated to casimersen or its dose. There were no deaths, dose reductions, abnormalities in laboratory parameters or vital signs, or casimersen-related serious AEs. Casimersen plasma concentration increased with dose and declined similarly for all dose levels over 24 hours postinfusion. All pharmacokinetic parameters were similar at weeks 7 and 60. DISCUSSION: Casimersen was well tolerated in participants with DMD amenable to exon 45 skipping. Most TEAEs were mild, nonserious, and unrelated to casimersen. Plasma exposure was dose proportional with no suggestion of plasma accumulation. These results support further studies of casimersen in this population.

Population pharmacokinetics-based recommendations for a single delayed or missed dose of nusinersen.

Nusinersen is an antisense oligonucleotide approved for the treatment of spinal muscular atrophy. The drug is given intrathecally at 12 mg, beginning with 3 loading doses at 2-week intervals, a fourth loading dose 30 days thereafter, and maintenance doses at 4-month intervals. This population pharmacokinetic model was developed to clarify how to maintain targeted nusinersen exposure after an unforeseen one-time delay or missed dose. Simulations demonstrated that the impact of a one-time delay in dosing or a missed dose on median cerebrospinal fluid exposures depended on duration of interruption and the regimen phase in which it occurred. Delays in loading doses delayed reaching the peak trough concentration by approximately the duration of the interruption. Resumption of the regimen as soon as possible resulted in achieving steady state trough concentration upon completion of the loading phase. A short delay (30-90 days) during the maintenance phase led to prolonged lower median cerebrospinal fluid concentration if all subsequent doses were shifted by the same 4-month interval. However, administration of the delayed dose, followed by the subsequent dose as originally scheduled, rapidly restored trough concentration. If a dose must be delayed, patients should return to the original dosing schedule as soon as possible.

Raltegravir 1200 mg once daily versus raltegravir 400 mg twice daily, with tenofovir disoproxil fumarate and emtricitabine, for previously untreated HIV-1 infection: a randomised, double-blind, parallel-group, phase 3, non-inferiority trial.

BACKGROUND: Once daily regimens are preferred for HIV-1 treatment, to facilitate adherence and improve quality of life. We compared a new once daily formulation of raltegravir to the currently marketed twice daily formulation. METHODS: In this randomised, double-blind, parallel-group, phase 3, non-inferiority study, we enrolled participants aged 18 years or older with HIV-1 RNA of 1000 or more copies per mL and no previous antiretroviral treatment at 139 sites worldwide. We randomly assigned participants (2:1) via an interactive voice and web response system to raltegravir 1200 mg (two 600 mg tablets) orally once daily or raltegravir 400 mg (one tablet) orally twice daily, each with tenofovir disoproxil fumarate and emtricitabine orally once daily, for up to 96 weeks. A computer-generated allocation schedule stratified randomisation by screening HIV-1 RNA value and co-infection with hepatitis B or C. Participants, sponsor personnel, investigators, and study site personnel involved in the treatment or evaluation of the participants were unaware of the treatment group assignments. The primary endpoint was the proportion of participants with HIV-1 RNA less than 40 copies per mL at week 48 assessed with the US Food and Drug Administration Snapshot algorithm. Non-inferiority was concluded if the lower bound of the two-sided 95% CI was greater than -10%. We assessed efficacy and safety in all participants who received one dose or more of study treatment. This study is registered with ClinicalTrials.gov, number NCT02131233. FINDINGS: Between May 26, 2014, and Dec 5, 2014, 802 participants were enrolled and randomly assigned, 533 to once daily treatment and 269 to twice daily; 797 received study therapy, 531 once daily and 266 twice daily. At week 48, 472 (89%) of 531 once daily recipients and 235 (88%) of 266 twice daily recipients achieved HIV-1 RNA less than 40 copies per mL (treatment difference 0·5%, 95% CI -4·2 to 5·2). Drug-related adverse events occurred in 130 (24%) of 531 participants in the once daily group (one of which was serious; none led to treatment discontinuation) and 68 (26%) of 266 participants in the twice daily group (two of which were serious; two led to treatment discontinuation). The most common drug-related adverse events were nausea (39 [7%] vs 18 [7%]), headache (16 [3%] vs 12 [5%]), and dizziness (12 [2%] vs eight [3%]). No treatment-related deaths were reported. INTERPRETATION: A once daily raltegravir 1200 mg regimen was non-inferior compared with raltegravir 400 mg twice daily for initial treatment of HIV-1 infection. These results support the use of raltegravir 1200 mg once daily for first-line therapy. FUNDING: Merck & Co, Inc.

Efavirenz does not meaningfully affect the single dose pharmacokinetics of 1200 mg raltegravir.

Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice daily (BID). Raltegravir for once daily regimen (QD) at a dose of 1200 mg (2 x 600 mg) is under development and offers a new treatment option for HIV-1 infected treatment-naive subjects. Since raltegravir is eliminated mainly by metabolism via an UDP-glucuronosyltransferase (UGT) 1 A1-mediated glucuronidation pathway, co-administration of UGT1A1 inducers may alter plasma levels of raltegravir. Efavirenz, an UGT1A1 inducer, was used to assess the impact of altered UGT activity on a 1200 mg QD dose of raltegravir. An open label, randomized, 2-period fixed-sequence Phase 1 study was performed in adult healthy male and female subjects (non-childbearing potential) ≥ 19 and ≤55 years of age, with a body mass index (BMI) ≥ 18.5 and ≤32.0 kg/m2 . Subjects (n = 21) received a single oral dose of 1200 mg raltegravir at bedtime on an empty stomach on Day 1 in Period 1. After a washout period of at least 7 days, subjects received oral doses of 600 mg efavirenz QD at bedtime for 14 consecutive days in Period 2. Subjects received a single oral dose of 1200 mg raltegravir co-administered with 600 mg efavirenz on Day 12 of Period 2. Pharmacokinetic (PK) samples were collected for 72 hours following raltegravir dosing and analyzed using a validated bioanalytical method to quantify raltegravir plasma concentrations. PK parameters were estimated using non-compartmental analysis. Administration of single 1200 mg oral doses of raltegravir alone and co-administered with multiple oral doses of efavirenz were generally well tolerated in healthy subjects. Co-administration with efavirenz yielded geometric mean ratios (GMRs) and their associated 90% confidence intervals (90% CIs) for raltegravir AUC0-∞, Cmax , and C24 of 0.86 (0.73, 1.01), 0.91 (0.70, 1.17), and 0.94 (0.76, 1.17), respectively. The results show that efavirenz modestly reduced the exposure of raltegravir. The reduction in raltegravir exposure is not considered clinically meaningful. Copyright © 2016 John Wiley & Sons, Ltd.

Atazanavir increases the plasma concentrations of 1200 mg raltegravir dose.

Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice-daily (b.i.d.). Raltegravir 1200 mg once-daily (q.d.) (investigational q.d. formulation of 2 × 600 mg tablets; q.d. RAL) was found to be generally well tolerated and non-inferior to the marketed 400 mg b.i.d. dose at 48 weeks in a phase 3 trial. Since raltegravir is eliminated mainly by metabolism via a uridine diphosphate glucuronosyltransferase (UGT) 1A1-mediated glucuronidation pathway, co-administration of UGT1A1 inhibitors may increase the plasma levels of q.d. RAL. To assess this potential, the drug interaction of 1200 mg raltegravir using atazanavir, a known UGT1A1 inhibitor, was studied. An open-label, randomized, 2-period, fixed-sequence phase 1 study was performed in adult healthy male and female (non-childbearing potential) subjects ≥ 19 and ≤ 55 years of age, with a body mass index (BMI) ≥ 18.5 and ≤ 32.0 kg/m2 . Subjects (n = 14) received a single oral dose of 1200 mg raltegravir in period 1. After a washout period of at least 7 days, the subjects received oral doses of 400 mg atazanavir q.d. for 9 consecutive days, with a single oral dose of 1200 mg raltegravir co-administered on day 7 of period 2. Serial blood samples were collected for 72 h following raltegravir dosing and analysed using a validated bioanalytical method to quantify raltegravir plasma concentrations. Co-administration with atazanavir yielded GMRs (90% CIs) for raltegravir AUC0-∞ , Cmax and C24 of 1.67 (1.34, 2.10), 1.16 (1.01, 1.33) and 1.26 (1.08, 1.46), respectively. There was no effect of raltegravir on serum total bilirubin. In contrast, atazanavir increased the mean bilirubin by up to 200%, an effect that was preserved in the atazanavir/raltegravir treatment group. Administration of single q.d. RAL alone and co-administered with multiple oral doses of atazanavir were generally well tolerated in healthy subjects. The results show that atazanavir increased the PK exposure of raltegravir; therefore, co-administration of atazanavir with raltegravir q.d. is not recommended. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of metal-cation antacids on the pharmacokinetics of 1200 mg raltegravir.

OBJECTIVES: Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice daily (BID). Raltegravir for once-daily regimen (QD) at a dose of 1200 mg is under development. The effect of calcium carbonate and magnesium/aluminium hydroxide antacids on the pharmacokinetics of a 1200 mg dose of raltegravir was assessed in this study. METHODS: An open-label, four-period, four-treatment, fixed-sequence study in 20 HIV-infected patients was performed. Patients needed to be on raltegravir as part of a stable treatment regimen for HIV, and upon entry into the trial received 5 days of 1200 mg raltegravir as pretreatment, before they entered the four-period study: 1200 mg of raltegravir alone (period 1), calcium carbonate antacid as TUMS® Ultra Strength (US) 1000 and 1200 mg raltegravir given concomitantly (Period 2), magnesium/aluminium hydroxide antacid as 20 ml MAALOX® Maximum Strength substitute MS given 12 h after administration of 1200 mg raltegravir (period 3), and calcium carbonate antacid as TUMS® US 1000 given 12 h after administration of 1200 mg raltegravir (period 4). Patients received their dose of 1200 mg QD raltegravir during the intervals between periods to re-establish steady state. AUC0-24 , C24 , Cmax and Tmax were calculated from the individual plasma concentrations of 1200 mg QD raltegravir after administration alone or with a calcium carbonate antacid or with a staggered dose of a calcium carbonate antacid or magnesium/aluminium hydroxide antacid. Adverse events, in addition to laboratory safety tests (haematology, serum chemistry and urinalysis), 12-lead electrocardiograms and vital signs were assessed. KEY FINDINGS: All treatments were well tolerated in the study. Metal-cation antacids variably affected the pharmacokinetics of 1200 mg QD raltegravir. When calcium carbonate antacid was given with 1200 mg raltegravir concomitantly, the geometric mean ratio (GMR) and its associated 90% confidence interval (90% CI) for AUC0-24 , Cmax and C24 h were 0.28 (0.24, 0.32), 0.26 (0.21, 0.32) and 0.52 (0.45, 0.61), respectively. When calcium carbonate antacid and magnesium/aluminium hydroxide were given 12 h after raltegravir 1200 mg QD dosing, the GMR (90% CI) values for AUC0-24 and Cmax were 0.90 (0.80, 1.03), 0.98 (0.81, 1.17), and 0.86 (0.73, 1.03), 0.86 (0.65, 1.15), respectively. However, significant reduction in the trough concentrations of raltegravir was observed: C24 h 0.43 (0.36, 0.51) in the presence of calcium carbonate antacids and 0.42 (0.34, 0.52) in presence of magnesium/aluminium hydroxide, respectively. CONCLUSIONS: Overall, the use of metal-cation antacids with 1200 mg QD raltegravir is not recommended.