MedPacto has announced the early termination of its phase 2 clinical trial of vactosertib combined with MSD’s Keytruda (pembrolizumab) for the first-line treatment of non-small cell lung cancer (NSCLC).

In a public disclosure on Monday, MedPacto said it has voluntarily dropped the phase 2 study evaluating the efficacy and safety of vactosertib in combination with Keytruda as a first-line treatment for patients with PD-L1-positive advanced NSCLC.

MedPacto received the protocol approval from the Ministry of Food and Drug Safety (MFDS) in August 2020 and has since conducted the trial at four hospitals, including Samsung Medical Center.

The trial’s objective was to evaluate the efficacy and safety of the combination of vactosertib and Keytruda as a first-line treatment for patients with NSCLC. The trial was an open-label, multicenter, single-arm, unblinded, open-label study in 55 patients scheduled for treatment for 24 months.

Beginning with the first patient dose in December 2020, MedPacto aimed to commercialize the combination therapy of vactosertib and Keytruda to target the 3.3 trillion won ($2.4 billion) NSCLC market.

The company expected the combo therapy to offer new therapeutic possibilities for patients with PD-L1 expression of 1 percent or more, a group of patients who have been difficult to treat with Keytruda alone.

However, MedPacto said it has revised its development strategy due to changes in the business and development environment.

The company said that due to positive results from the phase 2 study of the combination of AstraZeneca’s Imfinzi (durvalumab) and vactosertib as a second-line treatment for patients with advanced NSCLC, it has decided to change its development strategy to the combination with durvalumab.

In November 2020, MedPacto presented interim results from a phase 2a clinical trial of the combination with durvalumab at the U.S. Society for Immunotherapy of Cancer (SITC).