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RecruitingInterventionalPhase 1

An Open-label, Phase 1a/1b, Dose Escalation and Dose Expansion Study Investigating the Safety, Pharmacokinetics, Pharmacodynamics, and Antitumor Activity of PHST001 in Adult Patients With Advanced Relapsed and/or Refractory Solid Tumors

NCT ID: NCT06840886Sponsor: Pheast TherapeuticsLast updated: 2026-05-14

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 chemotherapy (Phase 1b) in adult participants with advanced relapsed and/or refractory solid tumors (including but not limited to CNS tumors in Phase 1a only). In Phase 1b cohort expansions, the study will focus on participants with advanced relapsed and/or refractory ovarian cancer, endometrial cancer, and cholangiocarcinoma. The study's primary objective is to evaluate the safety and tolerability of PHST001 and determine the RP2D (Recommended Phase 2 dose) of PHST001 monotherapy and in combination with chemotherapy as well as assess the anti-tumor activity of PHST001 and chemotherapy in Phase 1b.

Arms & interventions

  • BiologicalPHST001

    PHST001 is an anti-CD24 macrophage checkpoint inhibitor, administered as IV infusions every 3-weeks (Q3W) dosing intervals.

  • DrugChemotherapy per Standard of Care

    Participants will receive PHST001 at a dose level and schedule based on monotherapy data in Phase 1a. PHST001 will be combined with chemotherapeutic agents used as standard of care.

Outcome measures

Primary

  • Frequency of Dose-Limiting Toxicities (DLTs) to assess the safety and tolerability of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Based on toxicities observed

    Time frame: From first dose of PHST001 through 21 days after the first dose of PHST001

  • Frequency of Serious Adverse Events (SAEs) to assess the safety and tolerability of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Based on toxicities observed

    Time frame: From signed consent up to 90 days after the last dose of PHST001

  • Frequency of Treatment Emergent Adverse Events (TEAEs) to assess the safety and tolerability of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Based on toxicities observed

    Time frame: From first dose up to 90 days after the last dose of PHST001

  • Frequency of Treatment Related Adverse Events (TRAEs) to assess the safety and tolerability of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Based on toxicities observed

    Time frame: From first dose up to 90 days after the last dose of PHST001

  • Frequency of Adverse Events of Special Interest (AESIs) to assess the safety and tolerability of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Based on toxicities observed

    Time frame: From first dose up to 90 days after the last dose of PHST001

  • Frequency of AEs Leading to Dose Interruption or Treatment Discontinuation and AEs Leading to Death to assess the safety and tolerability of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Based on toxicities observed

    Time frame: From first dose up to 90 days after the last dose of PHST001

  • Overall Response Rate (ORR) based on RECIST v1.1 to assess the preliminary antitumor activity of PHST001 in combination with chemotherapy (Phase 1b)

    Defined as the proportion of subjects with confirmed complete response (CR) or partial response (PR); a confirmed response is a response that persists on repeat-imaging ≥ 4 weeks after initial documentation of response.

    Time frame: From screening and during treatment up to 2 years

  • Duration of Response (DOR) based on RECIST v1.1 to assess the preliminary antitumor activity of PHST001 in combination with chemotherapy (Phase 1b)

    Defined as time from date of first objective response (either CR or PR) to first documentation of radiographic disease progression.

    Time frame: From screening and during treatment up to 2 years

  • Best Overall Response (BOR) based on RECIST v1.1 to assess the preliminary antitumor activity of PHST001 in combination with chemotherapy (Phase 1b)

    Defined as the best response recorded for a participant across all time-point assessments from the start of treatment until disease progression or end of treatment.

    Time frame: From screening and during treatment up to 2 years

  • Progression-Free Survival (PFS) based on RECIST v1.1 to assess the preliminary antitumor activity of PHST001 in combination with chemotherapy (Phase 1b)

    Defined as the time from first dose of PHST001 to first documentation of radiographic disease progression or death, whichever occurs first.

    Time frame: From screening and during treatment up to 2 years

  • Overall Survival (OS) based on RECIST v1.1 to assess the preliminary antitumor activity of PHST001 in combination with chemotherapy (Phase 1b)

    Defined as the time from first dose of PHST001 to the date of death.

    Time frame: From screening and during treatment up to 2 years

Secondary

  • Overall Response Rate (ORR) based on RECIST v1.1 (or RANO for primary CNS Tumors) to assess the preliminary antitumor activity of PHST001 as monotherapy (Phase 1a)

    Time frame: From screening and during treatment up to 2 years

  • Duration of Response (DOR) based on RECIST v1.1 (or RANO for primary CNS Tumors) to assess the preliminary antitumor activity of PHST001 as monotherapy (Phase 1a)

    Time frame: From screening and during treatment up to 2 years

  • Best Overall Response (BOR) based on RECIST v1.1 (or RANO for primary CNS Tumors) to assess the preliminary antitumor activity of PHST001 as monotherapy (Phase 1a)

    Time frame: From screening and during treatment up to 2 years

  • Progression-Free Survival (PFS) based on RECIST v1.1 (or RANO for primary CNS Tumors) to assess the preliminary antitumor activity of PHST001 as monotherapy (Phase 1a).

    Time frame: From screening and during treatment up to 2 years

  • Overall Survival (OS) based on RECIST v1.1 (or RANO for primary CNS Tumors) to assess the preliminary antitumor activity of PHST001 as monotherapy (Phase 1a).

    Time frame: From screening and during treatment up to 2 years

  • Maximum Observed Concentration (Cmax) to characterize the serum PK of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b).

    Time frame: From treatment until 90 days after last dose of PHST001

  • Time to Maximum Concentration (tmax) to characterize the serum PK of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Time frame: From treatment until 90 days after last dose of PHST001

  • Concentration at the End of a Dosing Interval (Ctrough) to characterize the serum PK of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Time frame: From treatment until 90 days after last dose of PHST001

  • Area Under the Concentration-time Curve (AUC) to characterize the serum PK of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Time frame: From treatment until 90 days after last dose of PHST001

  • Volume of Distribution at Steady-state (Vss) to characterize the serum PK of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Time frame: From treatment until 90 days after last dose of PHST001

  • Clearance (CL) to characterize the serum PK of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Time frame: From treatment until 90 days after last dose of PHST001

  • Terminal Elimination Half-life (t½) to characterize the serum PK of PHST001 as monotherapy (Phase 1a) or in combination with chemotherapy (Phase 1b)

    Time frame: From treatment until 90 days after last dose of PHST001

Eligibility criteria

Sex: AllAge: 18 Years and olderHealthy volunteers: No
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 5 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, 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. Participants with previously treated CNS metastases may participate provided they are radiologically stable (i.e., 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 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.

Study locations (20)

Precision NextGen Oncology & Research Center

Beverly Hills, California, 90212

Not Yet Recruiting

USC Norris Comprehensive Cancer Center

Los Angeles, California, 90033

Recruiting

Stanford University School of Medicine

Palo Alto, California, 94304

Recruiting

Sarah Cannon Research Institute (SCRI) Oncology Partners - Denver Health One

Denver, Colorado, 80218

Recruiting

Yale Cancer Center

New Haven, Connecticut, 06520

Recruiting

University of Chicago Medical Center

Chicago, Illinois, 60637

Recruiting

Dana Farber Cancer Institute

Boston, Massachusetts, 02215

Recruiting

University of Michigan Rogel Cancer Center

Ann Arbor, Michigan, 48109

Recruiting

START Center for Cancer Research - Midwest

Grand Rapids, Michigan, 49546

Recruiting

START Center for Cancer Research - Long Island New York

Lake Success, New York, 11042

Recruiting

Mount Sinai

New York, New York, 10029

Not Yet Recruiting

Duke Cancer Institute

Durham, North Carolina, 27710

Recruiting

Sarah Cannon Research Institute (SCRI) Oncology Partners

Nashville, Tennessee, 37203

Recruiting

Vanderbilt-Ingram Cancer Center

Nashville, Tennessee, 37203

Recruiting

START Center for Cancer Research - Texas

Fort Worth, Texas, 76104

Recruiting

MD Anderson Cancer Center

Houston, Texas, 77030

Recruiting

NEXT Oncology - Dallas

Irving, Texas, 75039

Recruiting

South Texas Accelerated Research Therapeutics (START)

San Antonio, Texas, 78229

Recruiting

University of Texas (UT) Health

San Antonio, Texas, 78229

Not Yet Recruiting

NEXT Oncology - Virginia

Fairfax, Virginia, 22031

Recruiting