A Phase 1/1B Study of ST-01156 in Patients with Advanced Solid Malignancies

This Phase 1/1b study is evaluating the safety, tolerability, and preliminary anticancer activity of ST-01156 in participants with advanced solid malignancies. The study will be conducted in 2 parts. Part 1 (Dose Escalation) will assess the safety, tolerability, pharmacokinetics (PK) and preliminary anticancer activity of SD-01156 in participants with advanced solid malignancies, many of whom have a biological rationale to be targeted with an inhibitor of RBM39. Part 1 will also seek to determine the maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of ST-01156.

Inclusion Criteria:

• Age ≥ 18 years on the day of signing the consent form, except for adolescents with Ewing Sarcoma or other malignancies for which there is a biological rationale to support participation, in which case the participant is ≥ 16 years old.
• Has a metastatic or locally advanced and unresectable solid tumor.
• Has at least 1 measurable lesion or evaluable disease per RECIST v1.1.
• Has an ECOG performance status ≤ 2 at screening.
• Has adequate organ function as defined in the protocol.

Exclusion Criteria:

• Has received prior radiotherapy within 2 weeks of treatment.
• Has known active CNS metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate, provided they are radiologically stable
• Has received treatment with any local or systemic anticancer therapy or investigational anticancer agent within 14 days or 5 half-lives, whichever is shorter.
• Had major surgery within 28 days before study therapy administration
• Has toxicities from previous anticancer therapies that have not resolved to baseline levels, with the exception of alopecia and peripheral neuropathy.
• Has previously received a RBM39 inhibitor/degrader.