Study of PBI-200 in Subjects With NTRK-Fusion-Positive Solid Tumors

Key Inclusion Criteria:

   - 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.

Key Exclusion Criteria:

   - Cytotoxic chemotherapy, biologic agent, investigational agent, or radiation therapy ≤
   3 weeks prior to the first dose of PBI-200 (6 weeks for nitrosoureas).

      - Subjects with either primary brain tumors or brain metastasis must have completed
      brain radiation therapy 12 weeks prior to the brain MRI obtained within 4 weeks
      of the first dose of PBI-200.

   - Small-molecule kinase inhibitors or hormonal agents ≤ 14 days and within 5 half-lives
   prior to the first dose of PBI-200.