Immutep Limited (IMMP, IMM.AX) has reported encouraging outcomes from Cohort B of the TACTI-003 (KEYNOTE-PNC-34) Phase IIb trial. This study assessed the efficacy of eftilagimod alfa (efti) in combination with Merck & Co., Inc.'s (MRK) anti-PD-1 therapy, KEYTRUDA (pembrolizumab), as a first-line treatment for recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) patients, specifically those with negative PD-L1 expression.
On Thursday, IMMP's stock closed at $2.01, reflecting a modest increase of $0.01 or 0.50%. In after-hours trading, the stock saw a substantial rise, gaining $0.71 or 35.32%.
The investigational immuno-oncology combination of efti and KEYTRUDA achieved an objective response rate (ORR) of 35.5% and a disease control rate (DCR) of 58.1% according to RECIST 1.1 criteria, in 1L HNSCC patients whose tumors do not express PD-L1 (Combined Positive Score [CPS] less than 1). These results represent some of the highest recorded efficiencies for a chemotherapy-free approach in negative PD-L1 patients and compare favorably to historical control data, which showed an ORR of 5.4% and a DCR of 32.4% with anti-PD-1 monotherapy.
Additionally, the combination treatment also achieved a high complete response rate of 9.7%, significantly outperforming the historical control of 0% for anti-PD-1 monotherapy in 1L HNSCC patients with a CPS less than 1.
