The phase 2 clinical trial for preoperative adjuvant therapy, examining the Keytruda-GX-188E-GX-I7/NT-I7 triple combination in the treatment of HPV (human papillomavirus type)-positive head and neck cancer, initiated in 2022, is set to expand to include 56 patients this year.

Genexine and NeoImmuneTech said Monday that they had received protocol approval from the Ministry of Food and Drug Safety (MFDS) and institutional review board approval to initiate an additional cohort in the phase 2 clinical trial of GX-188E in head and neck cancer led by Professor Kim Hye-ryun of the Department of Medical Oncology at Severance Hospital.

GX-188E is a DNA-based therapeutic vaccine discovered by Genexine and developed in collaboration with the National Anticancer Drug and Therapy Development Corps, which works by inducing an antigen-specific T cell immune response against E6/E7, cancer-causing proteins produced by HPV types 16 and 18. It has an immuno-oncology mechanism that treats cancer cells by triggering a cytotoxic T lymphocyte response.

According to the results presented at the American Society of Clinical Oncology (ASCO) last year, all 11 patients in the trial did not experience any delay in surgery or increased complications. Seven (63.6 percent) and four (36.3 percent) patients with major pathologic response (MPR) and pathologic complete response (pCR) met the primary endpoint, confirming the primary efficacy and safety of the triple combination.

With support from Genexine and NeoImmuneTech, Professor Kim's team will add three cohorts, each comprising 15 patients to the existing 11, increasing the total to 56.

In each cohort, the dose and regimen of GX-188E 2 mg intramuscularly will remain the same. Still, the doses of Keytruda and GX-I7/NT-I7 will be changed in each cohort to explore further the role of each investigational drug in the triple combination therapy and their combined effects and to assess overall safety and major pathologic events.

The preoperative adjuvant therapy for head and neck cancer phase 2 study will evaluate the triple combination of GX-188E, GX-I7/NT-I7 (efineptakin alfa), and Keytruda in patients with HPV 16/18 positive, resectable, locally advanced squamous cell carcinoma of the head and neck. The mechanism of action is that GX-188E induces cancer cell-specific T-cell responses in HPV-16/18-induced head and neck cancer, GX-I7/NT-I7 amplifies the number of T-cells, and Keytruda blocks the immunosuppressive function of cancer cells against T-cells.

"Head and neck squamous cell carcinoma is a poor prognosis cancer arising from squamous epithelial cells of the head and neck, including the oral cavity, pharynx, and larynx, and is often associated with a high mortality rate," a company official said. "There are no immuno-oncology drugs for patients with HPV-positive head and neck cancer who are scheduled for surgery, and we hope that this trial will show that Keytruda can be effectively applied as an adjuvant therapy before surgery."