A Study of PHST001 in Advanced Solid Tumors

ID#: NCT06840886

Age: 18 years - 66+

Gender: All

Healthy Subjects: No

Study Phase: Phase 1

Recruitment Status: Recruiting

Start Date: March 31, 2025

End Date: April 01, 2031

Contact Information:
Raphaël Rousseau, Chief Medical Officer, PhD, MD
650-260-8443
Summary: This is a multi-center, first-in-human (FIH), open-label, Phase 1a/1b dose escalation and dose expansion study to assess the safety, PK, pharmacodynamics, and antitumor activity of PHST001 monotherapy (Phase 1a) or in combination with anticancer therapies (Phase 1b) in adult participants with advanced relapsed and/or refractory solid tumors (including but not limited to CNS tumors in Phase 1a only). Phase 1b will include the following cohorts 1) tumor-specific cohorts for participants with advanced relapsed and/or refractory ovarian cancer, endometrial cancer, and cholangiocarcinoma, 2) a randomized cohort for participants with ovarian cancer who will receive PHST001 in combination with mirvetuximab soravtansine, 3) a cohort for participants with advanced/metastatic breast cancer who will receive PHST001 in combination with trastuzumab deruxtecan and 4) a cohort of patients who consent to additional biomarker studies. The study's primary objectives are to evaluate the safety and tolerability of PHST001 and determine the RP2D (Recommended Phase 2 dose) of PHST001 as monotherapy and in combination with anticancer therapies, as well as to assess the anti-tumor activity of PHST001 in combination with anticancer therapies in Phase 1b.
Eligibility: Key

Inclusion Criteria:

- Histologically or cytologically confirmed advanced solid tumor which has relapsed from or been refractory to all locally available standard therapies.

- Adequate organ function per laboratory testing

- Pregnancy prevention requirements

- Measurable disease per RECIST v1.1 (or RANO) as assessed by the local site Investigator/radiology

- Performance status of 0 or 1 on Eastern Cooperative Oncology Group (ECOG) scale Key

Exclusion Criteria:

- Diagnosis of immunodeficiency

- History of a previous additional malignancy, unless potentially curative treatment has been completed, with no evidence of malignancy for 2 years. Participants with basal cell carcinoma of the skin, Stage I melanoma, melanoma in situ, squamous cell carcinoma of the skin, early-stage prostate cancer, low grade neoplasms, or carcinoma in situ, excluding carcinoma in situ of the bladder, who have undergone potentially curative therapy are not excluded and can be enrolled regardless of disease-free period following completion of potentially curative therapy. Participants with early-stage breast cancer who have undergone curative intent treatment and with no disease recurrence for 2 years after treatment are not excluded.

- Active known CNS metastases and/or carcinomatous meningitis from a systemic (non-CNS) primary malignancy. Participants with previously treated CNS metastases are eligible, provided they are radiologically and clinically stable (i.e., no evidence of progression for at least 2 weeks by repeat imaging performed during screening) and are not requiring systemic corticosteroids above the physiologic replacement for at least 7 days prior 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 study treatment. Participants must have recovered from all AEs due to previous therapies to Grade ≤1 or baseline. Participants with Grade ≤2 neuropathy may be eligible. Participants with endocrine-related AEs Grade ≤2 requiring treatment or hormone replacement may be eligible.

- Prior autologous or allogeneic hematopoietic stem cell transplant or solid organ transplant.

- Received previous treatment with another agent targeting CD24.
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