STCube Begins Phase 2 Trial for Non-Small Cell Lung Cancer: "First Patient Dosed"

STCube announced on January 22 that the first patient has been dosed in the Phase 2 clinical trial of its anti-BTN1A1 immune checkpoint inhibitor, Nelmastobart, for advanced and metastatic non-small cell lung cancer.

This Phase 2 clinical trial is designed to enroll patients with non-small cell lung cancer whose disease has progressed after first-line therapy and who exhibit high BTN1A1 expression (tumor proportion score [TPS] ≥ 50%). These patients will receive a combination treatment of Nelmastobart 800 mg and docetaxel 75 mg/m². The trial is being conducted at five university hospitals in Korea, with the first patient enrolled at Kangbuk Samsung Hospital.

For non-small cell lung cancer, targeted therapies are applied in the first-line treatment phase depending on the presence of gene mutations such as EGFR, KRAS, or BRAF. If major mutations are absent, immune checkpoint inhibitors are used either as monotherapy or in combination, depending on the level of PD-L1 expression. However, once patients move on to second-line or later treatment stages, they have essentially had to rely on docetaxel-based chemotherapy regimens.

Currently, the most widely used monotherapy with docetaxel in Korea offers a progression-free survival (PFS) of only about 3 months and an overall survival (OS) of about 6 months. Taking this treatment environment into account, STCube aims to provide a new therapeutic alternative for patients whose disease has progressed even after prior treatment with targeted or immune therapies.

According to STCube, BTN1A1 is observed to be highly expressed in approximately 50% of all non-small cell lung cancer patients. Therefore, not only does non-small cell lung cancer represent a potentially high-value market for BTN1A1-targeted therapies, but the ability to clearly observe differences in actual treatment response through biomarker-based patient selection also enhances both the clinical and business value.

Jung Hyunjin, CEO of STCube, stated, "This clinical trial in non-small cell lung cancer is not merely an expansion of indications, but a meaningful step in applying the biomarker standard of BTN1A1 expression to real-world patient treatment." He added, "In the subsequent treatment setting where options are limited, Nelmastobart offers a differentiated therapeutic approach for patients who have not responded sufficiently to standard treatments such as PD-1, PD-L1 inhibitors, and targeted therapies."

He continued, "With the addition of the non-small cell lung cancer indication to our BTN1A1-targeted strategy, the scope of clinical application and business development discussions surrounding Nelmastobart has expanded to a new level. As these changes are directly influencing the structure and depth of our ongoing technology transfer negotiations, we plan to rigorously manage both the pace of clinical progress and the completeness of our data."

STCube has already confirmed, through Phase 1b/2 clinical trials and investigator-initiated studies in metastatic colorectal cancer, that survival is significantly prolonged in patients with high BTN1A1 expression. The company believes that if this trend is replicated in non-small cell lung cancer, BTN1A1 is highly likely to be established as a novel biomarker for predicting immune-oncology treatment response.

Furthermore, by applying the clear criterion of BTN1A1 expression, the reliability of efficacy assessment and the clarity of result interpretation are both enhanced compared to non-selective trials. This is a key competitive advantage of biomarker-based clinical trial design.