UNISUS study design: a phase 3 superiority study comparing the efficacy, safety, and tolerability of macitentan 75 mg vs macitentan 10 mg in patients with pulmonary arterial hypertension (PAH)

Background

While advances in PAH-specific therapies have substantially improved survival, there is still an unmet need to improve long-term outcomes in PAH.

Purpose

The UNISUS study is the first head-to-head superiority study in PAH, comparing the time to morbidity or mortality (M/M) with macitentan 75 mg vs macitentan 10 mg in PAH patients.

Methods

UNISUS, an ongoing multicentre, prospective, double-blind (DB), adaptive, event-driven superiority study randomises PAH patients 1:1 to receive macitentan 75 mg or macitentan 10 mg, with a target enrolment of ∼900 patients. Efficacy and safety are continuously assessed by an independent data monitoring committee (IDMC), who advises on pre-specified adaptive changes in study conduct, including expansion of the study population. An independent clinical event committee adjudicates all M/M events. The initial population was restricted to patients in functional class (FC) II/III, aged 18–75 years and excluded those with portopulmonary hypertension (PoPH) and those who were PAH treatment-naïve or receiving a prostanoid analogue. Stable (≥3 months) background PAH-therapy may be maintained, except for endothelin receptor agonists (ERAs), which must be stopped the day before initiating study drug. The study is comprised of a screening period, a 4-week run-in period (if ERA treatment-naïve or on sub-optimal ERA dose), and an event-driven DB treatment period, followed by a 2-year open-label extension with macitentan 75 mg. Initiation of macitentan 75 mg occurs after a 4-week up-titration step with macitentan 37.5 mg (Figure 1). The primary endpoint is time to first on-treatment M/M event, defined as first of: all-cause death, PAH-related hospitalisation, or PAH-related disease progression (confirmed ≥15% decrease in 6-minute walk distance (6MWD) and either FC worsening or addition of PAH therapy). Other endpoints include change from baseline to Week 24 in 6MWD and PAH-SYMPACT symptom scores; time to PAH-related hospitalisation or death; time to all-cause death (may be supplemented with data from an external control arm derived from the CARE PAH study [NCT04955990]); and the safety and tolerability of the study drugs. Figure 2 shows planned assessments and sub-studies. To maximise patient retention, add-on PAH therapies are allowed after a M/M event and, for patients at risk of withdrawing and unable to attend visits, the investigator may consider options for reduced follow-up.

Results

After 60 patients had been exposed for ≥8 weeks, the IDMC reviewed unblinded safety/tolerability data and recommended to expand recruitment from the restricted population to the target population (i.e., including patients: with PoPH, in FC II–IV, from any PAH therapy background [including naïve], aged ≥18 years).

Conclusion

UNISUS is the first head-to-head superiority study in PAH; with over 200 patients enrolled, it is currently recruiting the target population.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Actelion Pharmaceuticals Ltd., a Janssen pharmaceutical company of Johnson & Johnson.

Susceptibility of Clostridium difficile isolates from a Phase 2 clinical trial of cadazolid and vancomycin in C. difficile infection

Objectives

The aim of this study was to evaluate the susceptibilities of Clostridium difficile isolates to cadazolid, a novel antibiotic for the treatment of C. difficile infection.

Methods

Ribotyping and susceptibilities were determined for C. difficile isolates from a multicentre, double-blind, Phase 2 study of oral cadazolid in patients with C. difficile infection (NCT01222702, ClinicalTrials.gov; EudraCT 2010-020941-29, European Clinical Trials Database). Patients were randomized to receive 250, 500 or 1000 mg of cadazolid twice daily or 125 mg of vancomycin four times daily, for 10 days. MICs of cadazolid, vancomycin, fidaxomicin, linezolid and moxifloxacin were determined at baseline for all patients and post-baseline for patients with clinical failure or recurrence, using the agar dilution method.

Results

Seventy-eight of 84 patients had an evaluable toxigenic C. difficile isolate at baseline. The most frequent PCR ribotype was 027 (15.4%). Cadazolid MICs for baseline isolates (including epidemic strain 027) ranged from 0.06 to 0.25 mg/L. Baseline cadazolid MICs were similar to those of fidaxomicin and lower than those of vancomycin, linezolid and moxifloxacin. For each clinical outcome group (clinical cure, clinical failure, sustained clinical response and clinical failure or recurrence), the baseline cadazolid MIC range was 0.06–0.25 mg/L. Mean (min–max) cadazolid faecal concentration (μg/g) on day 5 was 884 (101–2710), 1706 (204–4230) and 3226 (1481–12 600) for the doses 250, 500 and 1000 mg, respectively.

Conclusions

For all cadazolid doses, the faecal concentration was in excess of several thousand-fold the MIC₉₀ for C. difficile. The MIC of cadazolid for all C. difficile isolates, including epidemic strains, was low and in the same narrow range regardless of treatment outcome.