STCube Applies for IND for Innovative New Drug ‘hSTC810’ Phase 1 Clinical Trial

[Asia Economy Reporter Hyunseok Yoo] STCube, a bio company developing immune checkpoint inhibitors, announced on the 6th that it has submitted an Investigational New Drug application (IND) to the Ministry of Food and Drug Safety (MFDS) for Phase 1 clinical trial approval of its first-in-class drug candidate ‘hSTC810’.

‘hSTC810’ is an immune checkpoint inhibitor candidate targeting the ‘BTN1A1’ protein. The clinical trial application submitted by STCube to the MFDS is for a Phase 1, multinational, multicenter clinical trial to investigate the safety, tolerability, pharmacokinetics, and preliminary efficacy of ‘hSTC810’ monotherapy in patients with advanced solid tumors.

Through the clinical trial, STCube will evaluate the tolerability and safety of ‘hSTC810’ monotherapy and determine the maximum tolerated dose and maximum administered dose. Pharmacokinetic characteristics will be confirmed, and preliminary assessments of immunogenicity and anticancer effects will also be conducted. The clinical cohort will include up to 36 patients, with plans to increase the number of trial subjects through a backfill cohort depending on the results of the dose-escalation cohort.

The domestic clinical trial will be conducted at Severance Hospital in Sinchon. STCube plans to soon submit a global IND to the U.S. Food and Drug Administration (FDA), and multinational, multicenter clinical trials will be conducted at three globally prestigious cancer research institutions: MD Anderson Cancer Center, Yale Cancer Center, and Mount Sinai Hospital.

The target of ‘hSTC810’, ‘BTN1A1’, is an immune checkpoint protein first discovered worldwide by STCube. STCube discovered that ‘BTN1A1’ is expressed mutually exclusively with ‘PD-L1’, the target of existing immune checkpoint inhibitors, showing a synergistic effect. Additionally, ‘BTN1A1’ was found to act as an upstream regulator of ‘PD-L1’, which is used as a biomarker for existing immune checkpoint inhibitors.

In the tumor microenvironment, ‘BTN1A1’ shows a high expression rate in solid tumors where ‘PD-L1’ is poorly expressed. Experiments using STCube’s proprietary IHC antibodies demonstrated high expression of ‘BTN1A1’ in tumor cells of squamous cell lung cancer, head and neck cancer, bladder cancer, and breast cancer. Notably, it showed a high expression rate in several solid tumors known to have almost no expression of existing PD-L1.

STCube expects that the ‘hSTC810’ antibody targeting ‘BTN1A1’ will be a useful new immune checkpoint inhibitor for patients who are non-responsive to existing PD-1/PD-L1 therapies.

An STCube representative stated, “Although immune checkpoint inhibitors targeting ‘PD-1’ and ‘PD-L1’ have opened a new era in the anticancer drug market with excellent anticancer effects, only about 20-30% of patients benefit, and resistance issues have emerged, leaving unmet needs. We expect ‘hSTC810’ to help treat cancer patients who do not benefit from existing immune checkpoint inhibitors.”

He added, “Recently, various combination therapies have been attempted in clinical trials to overcome the limitations of therapies targeting ‘PD-1’ and ‘PD-L1’, but STCube is conducting monotherapy clinical trials with a novel target using a new biomarker. This clinical trial is expected to attract significant attention in the immune checkpoint inhibitor industry, and ‘hSTC810’ is anticipated to become another axis responding to existing ‘PD-1’ and ‘PD-L1’ therapies.”

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