Ascendis reports durable growth data from COACH and ApproaCH trials

Ascendis Pharma has released Week 78 data from its Phase 2 COACH trial and Week 104 data from the pivotal ApproaCH trial, reporting durable improvements in growth velocity and body proportionality in children with achondroplasia. The Copenhagen-headquartered biopharmaceutical company also updated investors on early commercial uptake of YUVIWEL, its once-weekly CNP prodrug approved by the FDA in February 2026.

In the COACH trial, children receiving combined TransCon CNP and TransCon hGH therapy maintained a mean annualised growth velocity (AGV) at or above the 97th percentile for children of average stature through 78 weeks. For the treatment-naïve cohort, mean AGV was 7.73 cm/year, with an ACH height Z-score rising from 0.46 to 1.75 over the period. In the previously TransCon CNP-treated cohort, mean AGV was 7.67 cm/year, with Z-score rising from 1.28 to 2.38. All 21 enrolled children completed Week 78 and remain on therapy, a retention rate the company described as consistent with prior readouts.

Monotherapy and pipeline milestones

The ApproaCH pivotal trial, evaluating TransCon CNP monotherapy in children aged 2 to 11, showed durable height improvements at Week 104 alongside benefits in lower-limb alignment and body proportionality. The company reported an injection-site reaction rate of 0.35 per person-year, all mild, and no treatment discontinuations. Carlos Bacino, Professor of Molecular and Human Genetics at Baylor College of Medicine and Texas Children's Hospital, said the data showed "positive effects compared to placebo on multiple aspects of skeletal growth, including statistically significant improvements in height and lower-limb alignment."

Ascendis also confirmed it has completed target enrolment for the pivotal reACHin trial, which evaluates TransCon CNP in infants aged under two years. That readout is expected to underpin planned regulatory filings for the youngest patient cohort. A Marketing Authorisation Application for TransCon CNP as monotherapy in children is under review in the European Union, with a decision anticipated in the fourth quarter of 2026.

Market context and competitive landscape

The achondroplasia treatment market has attracted meaningful competition over recent years. BioMarin's vosoritide (Voxzogo), a daily CNP analogue approved in the EU and U.S., remains the principal comparator for TransCon CNP. Ascendis's once-weekly dosing schedule differentiates YUVIWEL on convenience, which may influence both prescriber preference and adherence in a paediatric population. The COACH combination strategy, layering growth hormone on top of CNP pathway modulation, is a more ambitious approach with no direct approved comparator; the tripling-of-efficacy claim relative to monotherapy will attract scrutiny when full data are published.

Early commercial indicators are broadly positive. More than 170 patients have been enrolled by approximately 90 prescribing healthcare providers in the U.S., with over 65% securing reimbursement approval by 30 June 2026. Reimbursement access in rare paediatric conditions often starts slowly as payers assess health technology evidence; the rate seen here suggests payers are accepting YUVIWEL's clinical package, though the absolute number remains modest and the trajectory will be the key metric in coming quarters. The EU decision and an expanded label into the infant age group, if reACHin data support it, would represent material upside for the programme.