Novel IGSF8 Plus Keytruda Evaluated in Phase 1 Trial for Solid Tumors

A phase 1 trial is evaluating the safety and tolerability of two immune checkpoint inhibitors in patients with advanced solid tumors.

A combination of a novel checkpoint inhibitor IGSF8 plus Keytruda (pembrolizumab) is being evaluated in a phase 1 trial. Eligible patients in the trial have advanced solid tumors, according to a press release from GV20 Therapeutics, the manufacturer of IGSF8.

The investigational program called GV20-0251 included approximately 268 patients with advanced solid tumors, the listing on ClinicalTrials.gov stated. Specifically, patients included in the trial were refractory to approved treatments or standard-of-care.

Eligible conditions or disease types included solid tumors, refractory cancer, bladder cancer, cholangiocarcinoma (biliary tract cancer), colon cancer, endometrial cancer, head and neck cancers, cutaneous melanoma, non-small cell lung cancer and rectum cancer.

"We are excited to advance the development of GV20-0251 and explore its potential in combination with Keytruda," Dr. Shirley Liu, co-founder and CEO of GV20 Therapeutics, said in the press release.

READ MORE: 5 FDA Approvals for Solid Tumors in Early 2024

Immune checkpoint inhibitors are a type of drug that do not directly kill cancer cells, the American Cancer Society defines. Instead, these types of drugs stimulate the immune system so it can find and attack present cancer cells. Immune checkpoint inhibitors are typically received intravenously, or via an infusion in the vein.

The phase 1 trial is set to be conducted in two parts, ClinicalTrials.gov reported. Phase 1A of the trial will provide patients with a dose reduction to evaluate safety and to limit amounts of toxicities. This phase will also establish the maximum dose patients can tolerate or the recommended phase 2 dose of the novel drug.

During part A, the researchers will note the number of participants who experience dose-limiting toxicities and treatment-emergent side effects or serious side effects. According to the listing, the time frame will be one year.

In phase 1b of the trial, there will be expansion cohorts for eligible patients to be treated with the novel drug at the recommended phase 2 dose. The purpose will be to evaluate safety, tolerability, how well the drug is absorbed in the body and the physiologic actions of the drug. Researchers will also analyze the anti-tumor activity in the patient population, the listing stated.

Researchers in part B of the trial will review the overall response rate in a time frame of two years, ClinicalTrials.gov stated. The overall response rate is the percentage of patients whose tumors shrink or disappear after treatment, the National Cancer Institute defines.

The phase 1 trial is enrolling eligible patients with solid tumors who are refractory on standard-of-care, the press release noted. The trial began in March 2023 and is expected to be fully completed by mid-June 2026, according to ClinicalTrials.gov.

A representative of GV20 Therapeutics orally presented a session about IGSF8 as a novel immune checkpoint inhibitor and immunotherapy. The presentation was showcased at the American Association for Cancer Research (AACR) annual meeting 2024, the release stated.

"IGSF8 is a novel immune checkpoint target that inhibits the function of natural killer cells and dendritic cells,” Liu said. “By releasing this inhibition, the antagonistic antibody GV20-0251 has the potential to become another pillar in cancer immunotherapy and bring significant benefits to cancer patients."

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