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Study of STRO-002, an Anti-Folate Receptor Alpha (FolRα) Antibody Drug Conjugate in Ovarian & Endometrial Cancers

A Phase 1 Open-Label, Safety, Pharmacokinetic and Preliminary Efficacy Study of STRO-002, an Anti-Folate Receptor Alpha (FolRα) Antibody-Drug Conjugate (ADC), in Patients With Advanced Epithelial Ovarian Cancer (Including Fallopian Tube or Primary Peritoneal Cancers) and Endometrial Cancers

Status
Completed
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03748186
Enrollment
136
Registered
2018-11-20
Start date
2019-02-01
Completion date
2024-06-04
Last updated
2025-08-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Endometrial Cancer, Endometrioid Adenocarcinoma, Fallopian Tube Cancer, Ovarian Cancer, Ovarian Carcinoma, Ovary Cancer, Primary Peritoneal Carcinoma

Brief summary

Phase 1 trial to study the safety, pharmacokinetics and preliminary efficacy of STRO-002 given intravenously every 3 weeks.

Detailed description

This study is a phase 1, open-label, multicenter, dose-escalation study with dose expansion to identify the maximum tolerated dose (MTD), the recommended phase 2 dose (RP2D) and to evaluate the safety, tolerability, and preliminary antitumor activity of STRO-002 in adult subjects with advanced epithelial ovarian cancer (EOC), including fallopian or primary peritoneal cancer, and endometrial cancer. Fallopian tube and primary peritoneal cancers are treated in the same manner as epithelial ovarian cancers and are thus included in this phase 1 study. Subjects enrolled in the study will be required to have progressive or recurrent disease after standard approved therapy as defined in the study eligibility criteria. The study has completed dose escalation and is currently in dose expansion, enrolling endometrial and ovarian cancer subjects. All subjects enrolled on the study are required to have tumor tissue for determining folate receptor alpha (FolRα) expression levels, either from a prior surgery or tumor biopsy or from a biopsy performed during study screening. The testing for FolRα is done via an ICH assay. A minimum level of FolRα expression is required for enrollment for endometrial cancer but not for ovarian cancer. Study drug, STRO-002, is administered by intravenous (IV) infusion on day 1 of 21-day cycles. Clinical evaluations and/or laboratory tests will be performed at a pre-specified schedule-weekly for cycles 1-4, and at the beginning of every cycle starting with cycle 5 as described in the schedule of assessments. Samples for PK analysis will occur at specific times on days 1, 8, and 15 of cycles 1 and 4, Day 1 of cycles 2, 3, and 5 and at the end of treatment (EOT) visit. The study requires imaging with a CT or MRI scan of the chest abdomen and pelvis at screening, every 6 weeks after enrollment for the first 18 weeks, then every 9 weeks, and at the end of treatment (EOT) visit. Additional X-rays may be required to confirm disease responses and per local institution standard of care. Additional clinical evaluations and lab testing may occur at the discretion of the investigator.

Interventions

intravenous antibody drug conjugate

Sponsors

Sutro Biopharma, Inc.
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

The study is a modified 3+3 dose escalation study with a dose expansion. Dose escalation is in advanced ovarian cancer patients with relapsed or refractory disease to standard approved therapy. Dose expansion includes 2 cancer populations, ovarian cancer and endometrial cancer. The ovarian cancer expansion cohorts are Cohort A and Cohort C. Cohort A is a dose ranging design with randomization into 2 dose levels of STRO-002, 4.3 mg/kg and 5.2mg/kg. Cohort C is a single dose cohort design, STRO-002 5.2 mg/kg with prophylactic pegfilgrastim. Dose expansion in endometrial cancer (Cohort B) is a single dose cohort design, STRO-002 5.2 mg/kg. Endometrial subjects with prior pelvic irradiation will start treatment of STRO-002 at 4.3 mg/kg with step up to 5.2 mg/kg.

Eligibility

Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

1. Age ≥ 18 years 2. Measurable disease per RECIST 1.1 3. ECOG performance status (0-1) 4. Life expectancy \> 3 months 5. Pathological confirmation of disease under study (historical information, diagnosis, pathology report, etc) 1. Expansion Cohorts A and C: High-grade serous EOC, fallopian tube cancer or primary peritoneal cancer 2. Expansion Cohort B: Histologically diagnosed epithelial endometrial cancer (endometrioid and serous adenocarcinomas; undifferentiated carcinoma; mixed epithelial carcinoma; or adenocarcinoma NOS) 6. Relapsed and/or progressive disease 1. Dose Expansion Cohorts A and C (Ovarian Cancer): * Platinum resistant and received 1-3 prior regimens or * Platinum sensitive and either: * Progressed after 2 prior lines of platinum therapy (regardless of platinum status)and received 2-3 prior regimens or * Progressed after 1 line of platinum therapy and 1 line of non-platinum therapy and received a total of 2-3 prior regimens if contraindicated to receive second platinum regimen. 2. Dose Expansion Cohort B (Endometrial Cancer): * Relapsed or progression after at least 1 platinum-based chemotherapy regimen or 1 immunotherapy-based regimen but not to exceed more than 3 prior regimens. 7. Fresh or archival tumor tissue samples

Exclusion criteria

1. Low grade (grade 1) ovarian carcinoma, clear cell, mucinous and sarcomatous ovarian carcinomas (Cohort A). 2. Endometrial carcinosarcomas, leiomyosarcoma and stromal sarcomas (Cohort B). 3. Prior treatment with a FolRα-targeting ADCs or FolRα-targeting vaccines 4. Platinum-refractory during frontline treatment (Cohorts A and C) 5. Greater than 3 lines of prior treatment 6. History of severe allergic or anaphylactic reactions to monoclonal antibody therapy or to antibody-related fusion protein treatment 7. Preexisting clinically significant ocular disorders, clinically significant pre-exisiting ocular disorders, severe chronic obstructive pulmonary disease or asthma, clinically significant cardiac or cerebrovascular disease, or other significant concurrent, uncontrolled medical condition 8. Metastatic central nervous system or meningeal disease 9. Concurrent participation in another therapeutic treatment trial

Design outcomes

Primary

MeasureTime frameDescription
Part 2: Evaluate preliminary anti-tumor activity (endometrial cancer patients)24 monthsObjective response rate per RECIST 1.1
Part 1: Incidence of Treatment-Emergent Adverse Events (Safety and Tolerability of STRO-002)18 monthsIncidence of adverse events (AEs) observed across STRO-002 dose levels
Part 1: Define the recommended phase 2 dose (RP2D) of STRO-00218 monthsFrequency of dose-limiting toxicity and exposure across STRO-002 dose levels
Part 1: Define the maximum tolerated dose (MTD) of STRO-00218 monthsFrequency of dose-limiting toxicity and exposure across STRO-002 dose levels
Part 2: Evaluate preliminary anti-tumor activity (ovarian, Fallopian and primary peritoneal cancer patients)24 monthsObjective response rate per RECIST 1.1

Secondary

MeasureTime frameDescription
Part 1: Characterize the PK of STRO-002 by measuring the the steady state volume of distribution (Vss)18 monthsMeasurement of steady state volume of distribution
Part 1: Assess the formulation of anti-drug antibodies to STRO-00218 monthsCirculating anti-drug antibodies (ADAs) formed to STRO-002
Part 2: Further evaluate the incidence of Treatment-Emergent Adverse Events (Safety and Tolerability of STRO-002)24 monthsNumber of patients with abnormal laboratory values and/or adverse events related to STRO-002 treatment
Part 2: Evaluate preliminary anti-tumor efficacy with a time-to-event analysis of duration of response (DOR) in patients treated with STRO-00224 monthsDuration of response per RECIST 1.1
Part 2: Evaluate preliminary effect of STRO-002 treatment on CA-125 levels24 monthsResponse assessment based on the Gynecologic Cancer Intergroup (GCIG) criteria
Part 2: Characterize the PK of STRO-002 by measuring the maximum plasma concentration (Cmax)24 monthsMeasurement of maximum plasma concentration (Cmax) after the administration of STRO-002
Part 2: Characterize the PK of STRO-002 by measuring the area under the plasma concentration versus time curve (AUC)24 monthsMeasurement of AUC to infinity (AUC inf)
Part 2: Characterize the PK of STRO-002 by measuring the clearance (CL)24 monthsMeasurement of total body clearance
Part 2: Evaluate preliminary anti-tumor efficacy with a time-to-event analysis of progression-free survival (PFS) in patients treated with STRO-00224 monthsProgression-free survival per RECIST 1.1
Part 1: Characterize the pharmacokinetics (PK) of STRO-002 by measuring the maximum plasma concentration (Cmax)18 monthsMeasurement of maximum plasma concentration after the administration of STRO-002
Part 1: Characterize the PK of STRO-002 by measuring the half-life (t1/2) of STRO-00218 monthsMeasurement of terminal half-life of STRO-002 after the administration of STRO-002
Part 1: Characterize the PK of STRO-002 measuring the total area under the concentration versus time curve from zero to infinity (AUCinf)18 monthsMeasurement of AUC to infinity (AUCinf)
Part 1: Characterize the PK of STRO-002 by measuring the clearance (CL)18 monthsMeasurement of total body clearance

Other

MeasureTime frameDescription
Part 1: Preliminary assessment of the anti-tumor activity of STRO-00218 monthsObjective response rate per RECIST 1.1

Countries

Spain, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 21, 2026