• Subject has one of the following solid tumors which has progressed on or following at least one systemic therapy regimen administered for advanced or metastatic disease or for which no approved therapy exists:

⁃ NTRK-fusion-positive, locally advanced (i.e., not amenable to surgical resection) or metastatic solid tumor Note: Subjects with any grade of malignant glioma previously treated with systemic therapy are eligible.

‣ Phase 1

• NTRK-gene amplified, locally advanced or metastatic solid tumor

• EWSR1-WT1-positive DSRCTs.

• Subjects with NTRK-fusion-positive solid tumors other than primary brain tumors must have previously received treatment with a TRK inhibitor, unless the subject does not have access to TRK-inhibitor therapy (e.g., no TRK inhibitor is marketed and available to the subject in the subject's country) or the subject has declined treatment with available marketed TRK inhibitors.

• Subjects with NTRK-gene amplified solid tumors, primary brain tumors or EWSR1-WT1-positive DSRCTs may have received prior treatment with a TRK inhibitor but this is not required.

‣ Phase 2

• Has measurable disease by RECIST v1.1 for subjects with non-brain primary tumors or RANO criteria for subjects with primary brain tumors.

• Subjects with non-brain primary tumors must have previously received treatment with a TRK inhibitor and a documented resistance mutation(s) (e.g., solvent front, gatekeeper or xDFG mutation). Archival tissue from a prior biopsy taken after the subject completed TRK inhibitor treatment but prior to additional systemic therapy may be used to meet this eligibility criterion with Medical Monitor approval.

• Subjects with primary brain tumors may have received prior treatment with a TRK inhibitor but this is not required. Biopsies of brain tumors are not required for eligibility.