Ascendis Pharma A/S (Nasdaq: ASND) released Week 52 data from the open-label sentinel cohort of its reACHin Trial, showing that once-weekly TransCon CNP (navepegritide) stabilized or improved foramen magnum stenosis and supported linear growth in infants aged 0 to under 2 years with achondroplasia. The data were presented at the annual meeting of the European Society for Paediatric Endocrinology (ESPE 2026).

The sentinel cohort enrolled seven infants with a mean age of 11.7 months prior to the double-blind portion of the trial. All children showed stable or improved Achondroplasia Foramen Magnum Score between baseline and Week 52. The mean change from baseline in sagittal diameter of the foramen magnum was +3.15 mm, and no decompression surgeries were required during the period.

On growth outcomes, the mean change from baseline in achondroplasia-specific supine length Z-score was +0.42, with a mean annualized growth velocity of 9.9 cm/year.

Pharmacokinetics were described as comparable to those observed in older children, which the company said supports the 100 μg/kg/week dose used in the broader trial.

No injection site reactions were reported over the 52-week period. Investigators reported no deaths, fractures, bone-related safety events, or symptomatic hypotension. No adverse events were assessed as treatment-related, and none led to treatment disruption, discontinuation, or trial withdrawal.

The reACHin Trial is a Phase 2, randomized, placebo-controlled study evaluating the safety, tolerability, and efficacy of TransCon CNP in at least 66 treatment-naïve infants with genetically confirmed achondroplasia, followed by a 52-week open-label extension. The double-blind portion of the trial is now fully enrolled.