Ascendis scores in phase 3 trial as it looks to expand endocrine-focused portfolio

Ascendis Pharma checked off its top boxes in a phase 3 hypoparathyroidism trial, improving calcium levels in nearly 80% of patients treated and lessening disease severity.

Hypoparathyroidism (hypopara) is the underactivity of one or more parathyroid glands, which are responsible for producing calcium in the blood. Symptoms include muscle aches, twitching or spasms and a burning sensation in the toes, feet or lips. 

The PaTHway trial's primary endpoint was a composite measure of serum calcium levels and independence from conventional therapy with no increase in the study drug, TransCon PTH, within the four weeks prior to the week 26 visit. In the study, 78.7% of patients treated with the experimental drug achieved this primary goal, according to an announcement from the company Monday. By week 26, 95% of treated patients were able to shed conventional treatments.

The company also reported that there were no discontinuations due to treatment and only one treatment-emergent adverse effect in the treated arm as a result of a dosing error.

It’s the kind of data Ascendis was banking on as it looks to tack on to its endocrine-focused portfolio. In August 2021, the company won FDA approval for Skytrofa, its treatment for pediatric patients with an endogenous growth hormone deficiency. This January, the therapy got the greenlight from European regulators as well.

But it hasn’t been all peaches for the company looking to ride the momentum of its recent approvals, with the timeline of its phase 3 trial in adults with growth hormone deficiency thrown up in the air due to the ongoing war in Ukraine. The company is just one of a number of companies whose work and clinical trials have been impacted. 

The results do, however, bring the Danish pharma’s treatment for hypopara one step closer to the U.S. market, with the plan to apply for an NDA in the third quarter of this year. The company subsequently plans to apply for European authorization by the fourth quarter, in addition to launching a trial in kids with pediatric hypoparathyroidism.

The data reported today followed a 26-week blinded portion of the phase 3 trial that now embarks on an open-label extension study that will run for three years. 

In addition to improvements in calcium levels, the company reported that treated patients had a reduction in disease-related symptoms and disease impact compared to the control group. The treatment arm also had improved physical function. 

TransCon PTH is a hormone replacement therapy intended to boost parathyroid hormones. It acts as a prodrug, meaning it begins to take effect after its metabolized. 

On deck for Ascendis is top-line data from the company's phase 2 achondroplasia trial in children ages 2-10 expected sometime in the fourth quarter, the third of three endocrine-focused therapies in its pipeline, with plans to apply for human trials in kids ages 0-2 in the second quarter.