CROCuS, a Phase II Study Evaluating the Antiviral Activity, Clinical Outcomes, and Safety of Rilematovir in Children Aged ≥ 28 Days and ≤ 3 Years with Acute Respiratory Tract Infection Due to Respiratory Syncytial Virus

BACKGROUND

Respiratory syncytial virus (RSV) causes significant morbidity and mortality in children aged ≤ 5 years and adults aged ≥ 60 years worldwide. Despite this, RSV-specific therapeutic options are limited. Rilematovir is an investigational, orally administered inhibitor of RSV fusion protein-mediated viral entry.

OBJECTIVE

To establish the antiviral activity, clinical outcomes, safety, and tolerability of rilematovir (low or high dose) in children aged ≥ 28 days and ≤ 3 years with RSV disease.

METHODS

CROCuS was a multicenter, international, double-blind, placebo-controlled, randomized, adaptive phase II study, wherein children aged ≥ 28 days and ≤ 3 years with confirmed RSV infection who were either hospitalized (Cohort 1) or treated as outpatients (Cohort 2) were randomized (1:1:1) to receive rilematovir (low or high dose) or placebo. Study treatment was administered daily as an oral suspension from days 1 to 7, with dosing based on weight and age groups. The primary objective was to establish antiviral activity of rilematovir by evaluating the area under the plasma concentration-time curve of RSV viral load in nasal secretions from baseline through day 5. Severity and duration of RSV signs and symptoms and the safety and tolerability of rilematovir were also assessed through day 28 (± 3).

RESULTS

In total, 246 patients were randomized, treated, and included in the safety analysis population (Cohort 1: 147; Cohort 2: 99). Of these, 231 were included in the intent-to-treat-infected analysis population (Cohort 1: 138; Cohort 2: 93). In both cohorts, demographics were generally similar across treatment groups. In both cohorts combined, the difference (95% confidence interval) in the mean area under the plasma concentration-time curve of RSV RNA viral load through day 5 was - 1.25 (- 2.672, 0.164) and - 1.23 (- 2.679, 0.227) log10 copies∙days/mL for the rilematovir low-dose group and the rilematovir high-dose group, respectively, when compared with placebo. The estimated Kaplan-Meier median (95% confidence interval) time to resolution of key RSV symptoms in the rilematovir low-dose, rilematovir high-dose, and placebo groups of Cohort 1 was 6.01 (4.24, 7.25), 5.82 (4.03, 8.18), and 7.05 (5.34, 8.97) days, respectively; in Cohort 2, estimates were 6.45 (4.81, 9.70), 6.26 (5.41, 7.84), and 5.85 (3.90, 8.27) days, respectively. A similar incidence of adverse events was reported in patients treated with rilematovir and placebo in Cohort 1 (rilematovir: 61.9%; placebo: 58.0%) and Cohort 2 (rilematovir: 50.8%; placebo: 47.1%), with most reported as grade 1 or 2 and none leading to study discontinuation. The study was terminated prematurely, as the sponsor made a non-safety-related strategic decision to discontinue rilematovir development prior to full recruitment of Cohort 2.

CONCLUSIONS

Data from the combined cohort suggest that rilematovir has a small but favorable antiviral effect of indeterminate clinical relevance compared with placebo, as well as a favorable safety profile. Safe and effective therapeutic options for RSV in infants and young children remain an unmet need.

CLINICAL TRIAL REGISTRATION

EudraCT Number: 2016-003642-93; ClinicalTrials.gov Identifier: NCT03656510. First posted date: 4 September, 2018.

Ex situ conservation of Ruscus aculeatus L. - ruscogenin biosynthesis, genome-size stability and propagation traits of tissue-cultured clones

Ruscus aculeatus L. is a perennial semi-shrub with distinctive leaf-like branches (cladodes). Rhizomes and roots contain steroidal saponins (ruscogenins) that are used in medicine and cosmetics for their anti-inflammatory, venotonic and antihaemorroidal activity. Problematic cultivation of the species causes in many countries unsustainable over-collection from the wild. Tissue culture propagation of R. aculeatus was carried out for conservation and propagation purposes. The impact of the clonal origin (genotype) on the ruscogenin biosynthesis, genome-size stability and propagation traits and morpho-physiological response to long-term cultivation in vitro was studied. Production of ruscogenins in fully developed regenerants was quantified by high-performance liquid chromatography (HPLC). Genome-size stability of the clones was assessed by flow cytometry. Slow growth and prolonged lag-phase were characteristic for the whole propagation cycle. Produced plantlets with well-defined organs were suitable for direct ex vitro planting. Genome DNA content of all clones was stable and comparable to native plants. Ruscogenin biosynthesis was clone-specific, presenting distinctive profiles of the cultures. Our results imply that clone origin and culture type might influence saponin biosynthesis in Ruscus. These traits should be considered in the ex situ conservation of the genetic diversity of this species and by production of planting material as well.

Influence of plant origin on propagation capacity and alkaloid biosynthesis during long-term in vitro cultivation of Leucojum aestivum L

The investigation deals with in vitro clonal propagation of L. aestivum L. (summer snowflake), a threatened Amaryllidaceae plant species in Bulgaria used in the pharmaceutical industry as raw material for production of galanthamine-based medicines. Plants of known origin and with different alkaloid profile were taken from the living collection of the Institute of Botany, Sofia. Bulbs were used to initiate in vitro cultures and 24 clones were multiplied. The influence of the clone origin on the propagation coefficient, shoot and bulblet morphology, alkaloid profile and content of galanthamine, lycorine, and four related alkaloids was evaluated. Clones kept stable alkaloid profiles and for most of them, high regeneration rates were noted. Galanthamine content of some clones was commensurable with that of Bulgarian populations of L. aestivum of commercial importance. Five clones: four galanthamine-type and one lycorine-type were selected as promising for further investigation.

Clonal spread of carbapenem-resistant OXA-23-positive Acinetobacter baumannii in a Bulgarian university hospital

From October 1999 to September 2006, 29 carbapenem-resistant isolates of Acinetobacter baumannii were collected consecutively from patients hospitalized in different wards of the University Hospital in Pleven, Bulgaria. The bla(OXA-23) gene, associated with the upstream-located ISAba1, was identified as the mechanism responsible for carbapenem resistance in all isolates. The isolates belonged to two different clonal groups, indicating a sustained hospital outbreak. This study demonstrates both the epidemic potential of carbapenem-resistant A. baumannii and its longevity in the hospital environment.

The essential oil composition of Thymus tosevii and Thymus macedonicus from Bulgaria

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