Company strategy

The purpose of this clinical study is to assess the safety and efficacy of hSTC810 and paclitaxel combination therapy in patients with relapsed or refractory extensive stage small cell lung cancer.

The study will be conducted in 2 parts. Phase Ib will evaluate the safety of the combination of hSTC810 with a standard dose of paclitaxel using a 3+3 dose escalation design. Phase II will evaluate the efficacy of hSTC810 + paclitaxel combination therapy using a Simon 2-stage method.

Inclusion Criteria:

• Ability to understand and sign an informed consent form
• Male or female ≥ 18 years of age
• Histologically or cytologically confirmed SCLC
• R/R ES-SCLC on or after platinum-based chemotherapy for SCLC with documented disease progression
• At least 1 measurable lesion as defined by RECIST 1.1
• Eastern Cooperative Oncology Group Performance Score (ECOG PS) of 0 or 1
• Life expectancy of at least 3 months
• Adequate organ function as described in the protocol
• For female or male patients with reproductive potential: Agree to use contraception throughout the study and at least 5 months after the last dose.

Exclusion Criteria:

• Known active leptomeningeal disease (carcinomatous meningitis)
• Known active and uncontrolled central nervous system (CNS) metastases
• Treatment with immunotherapy, chemotherapy, targeted small molecule therapy, or any other investigational agent < 14 days prior to initiation of study treatment
• Treatment with radiation therapy < 14 days prior to initiation of study treatment
• Major surgery < 21 days prior to initiation of study treatment
• Received live vaccine < 30 days prior to initiation of study treatment, including intranasal influenza vaccine
• History of another primary malignancy with protocol-defined exceptions
• Active or history of autoimmune disease requiring systemic treatment
• Receiving high doses of steroids or other immunosuppressive medications
• Active hepatitis B or C infection
• Active or history of non-infectious pneumonitis requiring treatment with steroids
• Active uncontrolled viral, fungal, or bacterial infection including tuberculosis
• Pregnant or breastfeeding female patients
• History of severe hypersensitivity reaction to a monoclonal antibody treatment
• History of severe hypersensitivity reaction or ≥ Grade 3 adverse event (AE) to paclitaxel treatment
• History of cerebral vascular event, unstable angina, myocardial infarction, or cardiac symptoms within 6 months prior to screening
• QT Corrected for Fridericia's method (QTcF) > 470 ms at screening
• Lack of resolution of any toxicity to max Grade 1 (except alopecia)
• Active or history of any condition, therapy, or lab abnormality that may interfere with the patient participation for the full duration of the study
• Known psychiatric or substance use disorder
• Positive Coronavirus disease 2019 (COVID-19) test at screening