A Phase 1/1B Study of ST-01156, a Small Molecule RBM39 Degrader, in Patients With Advanced Solid Malignancies

Prior treatment

• 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.

• 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.