STC-15 as a Part of Combination Therapy With Toripalimab in Selected Advanced Cancers and as Monotherapy in Participants With Selected Sarcomas

• STC-15 in combination with toripalimab (Drug): STC-15 in combination with toripalimab in 21-day cycles
• STC-15 monotherapy (Drug): STC-15 monotherapy in 21-day cycles

Primary outcomes

• Combination Cohorts: Safety and tolerability of STC-15 in combination with toripalimab [6 months]: Incidence of adverse events graded according to CTCAE v5.0
• Phase 2 Monotherapy Cohorts: Antitumor activity of STC-15 monotherapy [6 months]: ORR according to RECIST

Secondary outcomes

• Combination Cohorts: Anti-tumor activity [6 months]: To evaluate the antitumor activity of STC-15 in combination with toripalimab as per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 and immune RECIST (iRECIST) criteria
• Combination and Phase 2 Monotherapy Cohorts: Maximum observed plasma concentration of STC-15 (Cmax) [22 days]
• Combination and Phase 2 Monotherapy Cohorts: Calculated time to reach maximum observed plasma concentration (Tmax) [22 days]
• Combination and Phase 2 Monotherapy Cohorts: Calculated area under the plasma concentration-time curve of STC-15 (AUC0-t) [22 days]
• Phase 2 Monotherapy Cohorts: Safety and tolerability of STC-15 [6 months]: Incidence of adverse events graded according to CTCAE v5.0

Sex: All, ages: 18 Years to any

Key Inclusion Criteria:

* Estimated life expectancy ≥ 3 months.
* ECOG performance status 0 or 1.
* Measurable disease according to RECIST v1.1 as assessed by the local site investigator/radiology.
* Documented radiologic assessment of progression on the prior therapy before study entry.
* Have adequate organ function.
* Have the ability to swallow, retain, and absorb oral medication.

Inclusion Criteria (Phase 2 Monotherapy Cohorts):

* Have histologic or cytologic confirmation of advanced sarcoma of the selected histologic subtype that is not amenable to local curative therapy. Participant must have received at least 2, but no more than 4 prior lines of systemic therapy.
* Pre-treatment and on-treatment biopsy if medically feasible.

Key Exclusion Criteria:

* Pregnant and lactating women.
* Received prior systemic anticancer therapy including investigational agents within 4 weeks or 5 half-lives, whichever is shorter, prior to first IMP administration.
* Participants who have not recovered from all AEs due to previous therapies to Grade ≤ 1 or baseline, according to NCI-CTCAE v5.0. Exceptions include: alopecia, Grade ≤ 2 neuropathy, and endocrine-related AEs Grade ≤ 2 who are stable on treatment or hormone replacement.
* History of (non-infectious) pneumonitis/interstitial lung disease that required steroids or the presence of ongoing pneumonitis/interstitial lung disease).
* Clinically significant cardiovascular disease or condition.
* Known active CNS metastases and/or leptomeningeal disease.

• Sandra Tong, MD, Study director, Storm Therapeutics