Immutep (ASX:IMM) has achieved 50% of its patient enrollment target in the TACTI-004 phase three trial, testing eftilagimod alfa in combination with Merck's Keytruda and chemotherapy as a first-line therapy for advanced or metastatic non-small cell lung cancer, according to a Friday Australian bourse filing.

The trial has enrolled 378 patients across more than 140 sites in 27 countries, per the filing.

It seeks to increase response rates to anti-PD-1 therapy across all PD-L1 levels while improving clinical outcomes and patient survival, the filing said.

Patient enrollment and the scheduled futility analysis are proceeding as planned, with complete enrollment anticipated by the third quarter, the filling added.