Dr Doger de Spéville on Key Efficacy Findings From Part C of TACTI-002 in HNSCC

Bernard Doger de Spéville, MD, PhD, medical oncologist, member, Early Phase Clinical Trials Unit, START Madrid-Fundacion Jimenez Diaz, Madrid, Spain, discusses key findings from part C of the phase 2 TACTI-002 trial (NCT03625323) of eftilagimod alpha (efti; IMP321) plus pembrolizumab (Keytruda) as second-line treatment for patients with head and neck squamous cell carcinoma (HNSCC).

Part C of TACTI-002 investigated the ability of eftilagimod alpha, a first-in-class MHC class II agonist, to strengthen patients' antitumor responses when combined with pembrolizumab. The trial enrolled patients with HNSCC who were unselected for PD-L1 expression and experienced disease progression on or after platinum-based chemotherapy. A total of 39 patients were enrolled, and 37 were evaluable for efficacy.

Final results presented at the 2023 ASCO Annual Meeting showed that eftilagimod alpha plus pembrolizumab produced an overall response rate (ORR) of 29.7% per immune-modified RECIST criteria, including a complete response (CR) rate of 13.5%, and responseswere observed irrespective of PD-L1 expression. Patients with a PD-L1 combined positive score (CPS) of at least 1 (n = 25) experienced an ORR of 38.5%. In patients with a PD-L1 CPS of 20 or greater (n = 15) achieved an ORR of 60%. At median follow-up of 39 months, the median duration of response was not reached in the overall population or either PD-L1 subgroup. The ORR rates compared favorably to other reported results with anti-PD-1 monotherapy in platinum-refractory metastatic HNSCC, such as the phase 3 KEYNOTE-048 study (NCT02358031) of pembrolizumab, Doger de Spéville emphasizes.

Regarding safety, the combination was very well tolerated, and no new safety signals were observed in part C, Doger de Spéville continues. Since eftilagimod alpha is delivered subcutaneously, injection site reaction was a common adverse effect (AE), Doger de Spéville notes. However, these AEs were predominantly low-grade, he adds.

Further evaluation of the combination of eftilagimod alpha and pembrolizumab is being conducted in the ongoing phase 2 TACTI-003 trial (NCT04811027) in patients with recurrent or metastatic HNSCC.

Disclosures: Dr Doger de Spéville had no relationships to disclose.