Immutep (ASX:IMM) said its Phase II EFTISARC-NEO trial evaluating the therapy of the company's drug candidate eftilagimod alfa, in combination with prescription medicine Keytruda and radiotherapy as treatment for patients with resectable soft tissue sarcoma (STS), showed an increase in tumor fibrosis rate, according to a Monday filing with the Australian bourse.

The trial showed that the combination therapy exceeded the median tumor fibrosis rate of 35% compared to the historical median of 15% observed with radiotherapy alone, meeting the trial's primary endpoint, the filing said.

Tumor fibrosis is linked to improved overall and recurrence-free survival in patients with STS.