Ascendis' Dual-Therapy Approach Shows Sustained Growth Benefits for Achondroplasia Patients

Ascendis Pharma A/S (ASND) released encouraging Week 52 data from its COACH Phase 2 trial, evaluating a combination regimen of once-weekly TransCon CNP paired with TransCon hGH injections in pediatric achondroplasia patients. The findings underscore how targeted combination therapy can achieve meaningful improvements in growth velocity while maintaining a robust safety profile throughout the treatment period.

Understanding Achondroplasia and the Clinical Need

Achondroplasia, accounting for the majority of dwarfism cases, stems from FGFR3 gene mutations that disrupt normal bone development. Beyond short stature, affected children contend with disproportionate limb-to-torso ratios and associated health complications. Current therapeutic options have been limited, making novel combination approaches a significant step forward in managing this rare genetic disorder.

Trial Results Paint a Compelling Picture

The COACH trial enrolled both treatment-experienced and treatment-naïve pediatric patients. At the 52-week checkpoint, therapy-naïve subjects achieved an annualized growth velocity of 8.8 cm annually—representing a 3.9 cm improvement over baseline measurements. Those previously exposed to TransCon CNP monotherapy reached 8.42 cm per year, with a 3.28 cm baseline gain. Enhanced height Z-scores across both cohorts validated that the combination approach outperformed single-agent therapy.

The safety data proved reassuring: the regimen was generally well-tolerated with predominantly mild adverse events. Notably, neither symptomatic hypotension nor fractures emerged as complications, and all enrolled children completed the full treatment duration without dropout.

Why Combination Therapy Matters

The synergistic effect of pairing TransCon CNP with intermittent hGH supplementation addresses achondroplasia’s multifaceted impact. Beyond incremental height gains, patients showed measurable improvements in body proportionality and arm span—metrics that translate to enhanced functional outcomes and quality of life, not merely growth metrics on a chart.

The consistency of results over 52 weeks suggests the benefits remain durable rather than transient, positioning this dual-therapy framework as a potential long-term management strategy for achondroplasia.

Looking Forward: Next-Generation Trials and Market Positioning

Ascendis has charted an ambitious regulatory roadmap. The company plans to launch a pivotal Phase 3 program comparing TransCon CNP monotherapy with the combination regimen, while concurrently advancing its standalone TransCon CNP U.S. and European regulatory submissions. A longer-term goal includes developing a single-injection formulation, streamlining administration for patients and caregivers alike.

Beyond achondroplasia, Ascendis intends to leverage its TransCon platform technology into adjacent endocrine and rare disease spaces, expanding the therapeutic footprint of this proprietary approach.

Financial Snapshot and Stock Performance

As of Q3, Ascendis maintained approximately €539 million in cash, cash equivalents, and marketable securities, providing runway for ongoing development initiatives. ASND stock has fluctuated between $118.03 and $229.94 over the trailing 12 months, closing the most recent session at $208.75, reflecting a 2.12% decline.

The COACH trial outcomes represent a pivotal moment for achondroplasia therapeutics, signaling that thoughtfully designed combination regimens can deliver tangible clinical progress for a patient population historically underserved by pharmaceutical innovation.