A Study of PHST001 in Advanced Solid Tumors

Key Inclusion Criteria:

• Histologically or cytologically confirmed advanced solid tumor which has relapsedfrom or been refractory to all locally available standard therapies.

• Adequate hepatic function:

• AST and ALT ≤ 2.5 × times ULN (≤ 5 × ULN if liver metastases)

• Total bilirubin ≤ 1.5 × ULN (<3 ×ULN for patients with elevations due to Gilbertsyndrome)

• Lipase and amylase ≤ 2×ULN

• Adequate renal function: calculated creatinine clearance of ≥ 30 mL/min calculatedper institutional standard

• Adequate bone marrow function without packed RBC transfusion within the prior 2weeks. Patients can be on a stable dose of erythropoietin (approximately ≥ 3months). Criteria must be met without platelet transfusion within 7 days ofscreening blood draw:

• Absolute neutrophil count (ANC) ≥1,500/µL

• Platelet count ≥100,000/µL

• Hemoglobin ≥9.0 g/dL or ≥5.6 mmol/La

Key Exclusion Criteria:

• History of a previous additional malignancy, unless potentially curative treatmenthas been completed, with no evidence of malignancy for 5 years. Patients with basalcell carcinoma of the skin, Stage I melanoma, melanoma in situ, squamous cellcarcinoma of the skin, early-stage prostate cancer, or carcinoma in situ, excludingcarcinoma in situ of the bladder, who have undergone potentially curative therapyare not excluded and can be enrolled regardless of disease-free period followingcompletion of potentially curative therapy. Patients with early-stage breast cancerwho have undergone curative intent treatment and with no disease recurrence for 2years after treatment are not excluded.

• Active known CNS metastases and/or carcinomatous meningitis. Patients withpreviously treated CNS metastases may participate provided they are radiologicallystable (ie, without evidence of progression for at least 2 weeks by repeat imaging [note that the repeat imaging should be performed during study screening]),clinically stable, and without requirement of steroid treatment for at least 14 daysprior to the first dose of study treatment.

• Received prior systemic anticancer therapy including investigational agents within 21 days or, if shorter, within 5 half-lives prior to the first dose of studytreatment. Patients must have recovered from all AEs due to previous therapies toGrade ≤1 or baseline. Patients with Grade ≤2 neuropathy may be eligible. Patientswith endocrine-related AEs Grade ≤2 requiring treatment or hormone replacement maybe eligible.

• Prior autologous or allogeneic hematopoietic stem cell transplant or solid organtransplant.

• Received previous treatment with another agent targeting CD24.