STCube Starts Clinical Trial for Small Cell Lung Cancer... "Pioneering Treatment Area"

STCube, an immuno-oncology drug development company, has officially launched clinical trials for 'Nelmastovat (hSTC810)', the world's first anti-BTN1A1 immune checkpoint inhibitor with a novel therapeutic mechanism, targeting small cell lung cancer (SCLC). The goal is to rapidly proceed with clinical procedures as a second-line or later treatment for SCLC, which currently lacks effective therapies.

On the 14th, STCube announced that it has started dosing the first patient in the Phase 1b/2 clinical trial of the innovative drug Nelmastovat for SCLC.

SCLC is known as a type of lung cancer with poor prognosis, ranking first in cancer mortality. It progresses rapidly and is highly malignant, with over 70% of SCLC patients diagnosed with 'extensive-stage small cell lung cancer,' where tumors have metastasized to the opposite lung or other sites. The 5-year survival rate for patients with extensive-stage SCLC is less than 5%.

The problem lies in the low efficacy and limited options of first- and second-line standard treatments for SCLC. First-line standard treatment mainly involves platinum-based chemotherapy combined with immune checkpoint inhibitors such as Tecentriq (atezolizumab) or Imfinzi (durvalumab), but complete cures from first-line treatment alone are extremely rare. As the disease progresses, most patients receive second-line treatments, but the efficacy of these second-line therapies remains poor.

An STCube representative stated, "SCLC has a high failure rate in first-line treatment and most second-line therapies show low efficacy, creating a significant unmet need for new second- and third-line treatments. Even in the case of the PD-L1-based Tecentriq combination therapy used as first-line standard treatment, overall survival (OS) improves by only about two months compared to the control group, making second-line treatment essential."

They continued, "The core of this clinical trial is that BTN1A1 is expressed exclusively from the existing PD-L1 protein, offering a new therapeutic strategy. Especially since BTN1A1 expression is high in dormant cancer cells involved in recurrence and metastasis, excellent results are expected in the treatment of SCLC."

Through the Phase 1b/2 trial, STCube will evaluate the efficacy and safety of the combination therapy of paclitaxel and Nelmastovat in patients with recurrent or refractory extensive-stage SCLC who have not responded to existing standard treatments.

In Phase 1b, dose-limiting toxicity (DLT) rates of the combination therapy will be assessed in up to 12 patients. Subsequently, in Phase 2 with up to 118 patients, the objective response rate (ORR) at 12 weeks and progression-free survival (PFS) at 24 weeks will be evaluated.

The representative added, "Based on Nelmastovat's unique mechanism of action, which is exclusively expressed apart from existing anti-PD-L1 immuno-oncology therapies, the combination therapy of paclitaxel and Nelmastovat is expected to show a high response rate in SCLC patients who have failed standard treatments. This will offer new hope for the treatment of extensive-stage SCLC."