United Therapeutics has reported that Unituxin (dinutuximab) in combination with irinotecan failed to meet the primary endpoint in a Phase II/III DISTINCT clinical trial involving patients with small cell lung cancer (SCLC).

Unituxin combination did not extend overall survival when compared to irinotecan alone, which was the trial’s primary efficacy objective.

Data further showed that the safety profile of United Therapeutics’ drug was consistent with its previous data and the existing product label.

Unituxin is a monoclonal antibody designed to attach to a disialoganglioside, GD2. It is indicated to treat high-risk neuroblastoma in certain paediatric patients when given with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-2 (IL-2) and 13-cis-retinoic acid (RA).

The two-part, open-label, randomised, international, multi-centre Phase II/III DISTINCT trial assessed Unituxin plus irinotecan as second-line therapy in patients with relapsed or refractory SCLC.

DISTINCT was conducted at 198 centres in 22 countries in North America, Europe and Asia-Pacific. Data analysis showed a total of 312 deaths across both treatment groups.

United Therapeutics chief medical officer Gil Golden said: “We’re clearly disappointed with the DISTINCT results but we’ll continue to seek out underappreciated avenues in our core therapeutic areas addressing rare diseases in oncology and pulmonary hypertension.

“In addition, we look forward to announcing the results of our INCREASE study by the end of the first quarter or shortly thereafter.”

The company also intends to seek approval for Unituxin in combination with irinotecan and temozolomide to treat paediatric patients with relapsed or refractory neuroblastoma.

United Therapeutics will meet the FDA in the first half of this year to discuss the label expansion based on the ANBL1221 study data and plans to submit a supplemental biologics license application at a later date.