Ascendis posts ApproaCH Phase 3 growth data behind already-approved Yuviwel
Posted results show navepegritide beat placebo on growth velocity in children 5 and older, a subgroup result that lands after the drug's FDA approval and priority review.
Executive Summary
- Ascendis Pharma A/S disclosed results from its pivotal achondroplasia trial, and the growth-velocity advantage it reports is concentrated in an age-defined subgroup rather than confirmed across the full randomized population.
- The data post after the FDA already approved the drug for this indication under priority review, so the trial's job now is to support the label already granted, not to determine whether the drug reaches the market.
- The new result extends a Phase 2 finding from an earlier trial in the same program that already showed the same drug beating placebo on the same growth measure, making this a replication test rather than a first read.
- The open question is whether the full study population, not just the older-child subgroup, shows the same separation from placebo, since the sponsor's own data flag marks the current disclosure as subgroup-limited.
The disclosure
Ascendis Pharma A/S (Ascendis) posted results for NCT05598320, the Phase 2/3 ApproaCH trial testing once-weekly subcutaneous navepegritide (TransCon CNP) against placebo in 84 children with achondroplasia. The trial's registered primary endpoint is annualized growth velocity at Week 52, measured as the change in height per year relative to baseline. The posted result the sponsor highlighted covers the subgroup of children age 5 and older at enrollment, a group of 53 of the 84 randomized participants, in which navepegritide showed a growth-velocity advantage over placebo at Week 52 sustained through as much as two years of follow-up, with a safety profile described as similar to the overall population. NCT05598320A Clinical Trial to Evaluate Efficacy and Safety of TransCon CNP Compared With Placebo in Children With AchondroplasiaNCT05598320
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
Already approved
The disclosure lands after the drug has already cleared FDA review. Navepegritide is approved under the brand name Yuviwel (NDA219164), and Ascendis received FDA priority review on the application before the agency granted the drug orphan drug exclusivity through February 27, 2033, for increasing linear growth in children 2 years and older with achondroplasia with open growth plates. A Marketing Authorisation Application is also under review at the European Medicines Agency, with a decision anticipated in the fourth quarter of 2026. That sequence means the ApproaCH result now functions as confirmatory clinical evidence behind a marketed product, not as the data package the approval decision itself turned on.
The design
ApproaCH randomized 84 children age 2 to 11 with genetically confirmed achondroplasia to weekly subcutaneous navepegritide at 100 micrograms per kilogram or placebo for a 52-week double-blind period, followed by a 52-week open-label extension in which all participants received the active drug. The trial ran across the United States, Australia, Canada, Denmark, Ireland, New Zealand, and Spain. Safety data covering adverse events showed 3 serious events among 57 participants on navepegritide and 3 among 27 on placebo during the double-blind period, with no deaths reported in either arm. NCT05598320A Clinical Trial to Evaluate Efficacy and Safety of TransCon CNP Compared With Placebo in Children With AchondroplasiaNCT05598320
Replication, not first evidence
The same drug already produced a positive readout on the identical endpoint in an earlier trial in the program. An earlier Phase 2 trial in the same program, also run by Ascendis, reported that navepegritide at the same 100-microgram weekly dose was superior to placebo on annualized growth velocity at 52 weeks among 57 randomized children. ApproaCH was designed to confirm that finding in a larger, registrational population; the subgroup result now disclosed extends it in the older-child cohort rather than establishing a new mechanism.
The field
Among trials sharing navepegritide's NPR-B agonist mechanism in achondroplasia, none of four completed Phase 2 studies has been reported as a failure, though the denominator is small. BioMarin's vosoritide, a direct comparator on target and modality, is in Phase 3 testing for the related condition hypochondroplasia and has additional Phase 2 and 3 programs running in achondroplasia itself, and BioMarin's next-generation NPR-B agonist BMN 333 has entered Phase 2/3 testing in the same indication. That keeps navepegritide inside a small but active NPR-B-targeted field rather than standing alone. [analogs]
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.