A Phase 2 Study of Mirvetuximab Soravtansine (IMGN853) and Pembrolizumab in Endometrial Cancer (EC)

A Phase 2, Two-stage, Study of Mirvetuximab Soravtansine (IMGN853) in Combination With Pembrolizumab in Patients With Microsatellite Stable (MSS) Recurrent or Persistent Endometrial Cancer (EC)

This research study is studying a drug combination as a possible treatment for endometrial cancer.

The drugs involved in this study are:

• mirvetuximab soravtansine (IMGN853)
• pembrolizumab

Study Overview

• Status: Active, not recruiting
• Conditions: Endometrial Cancer
• Intervention / Treatment: Drug: Pembrolizumab; Drug: IMGN853

Detailed Description

This research study is a Phase II clinical trial. Phase II clinical trials test the safety and effectiveness of an investigational drug to learn whether the drug works in treating a specific disease. "Investigational" means that the drug is being studied.

The FDA (the U.S. Food and Drug Administration) has not approved mirvetuximab soravtansine for this specific disease but it has been approved for other uses.

The FDA (the U.S. Food and Drug Administration) has not approved pembrolizumab for this specific disease but it has been approved for other uses.

In this research study, the investigators are studying the combination of mirvetuximab soravtansine and pembrolizumab. Pembrolizumab is an immunotherapy that activates a patient's own immune system to recognize and kill tumor cells. Pembrolizumab by itself may not be enough to kill cancer cells in all people with cancer. In this study, all patients will receive mirvetuximab soravtansine and pembrolizumab. Mirvetuximab soravtansine is an antibody-drug conjugate. That is a type of agent that attaches a chemotherapy drug to a molecule that binds a protein on the outside of cancer cells. The protein targeted by mirvetuximab soravtansine is called folate receptor-alpha (FRα). FRα is expressed on the surface of certain cancers, including endometrial cancer cells. Mirvetuximab soravtansine is expected to kill cancer cells by delivering chemotherapy to cells that have high levels of FRα. To participate in this study, a sample of your tumor was previously tested, and was found to have high levels of FRα. Mirvetuximab soravtansine also may also active immune cells and improve the response to immunotherapies like pembrolizumab.

In this study, the investigators expect to learn whether the combination of pembrolizumab and mirvetuximab soravtansine can shrink endometrial cancers or prevent their growth for at least 6 months. The investigators will also learn more about the side effects patients experience who receive this treatment. The investigators also plan to learn more about which patients are likely to benefit from this treatment

• Study Type: Interventional
• Enrollment (Actual): 18
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02215
      • Dana Farber Cancer Institute
    • Worcester, Massachusetts, United States, 01605
      • University of Massachusetts
  • New York
    • Lake Success, New York, United States, 11042
      • Northwell Cancer Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participants must have advanced or recurrent serous endometrial cancer. Patients with mixed histologies/tumors are eligible if the serous component is the dominant histological subtype. In addition, the tumors must be:
• microsatellite stable (MSS) as documented by either intact immunohistochemical (IHC) nuclear expression of the mismatch repair genes MSH2, MSH6, MLH1 and PMS2; or microsatelitte stable by polymerase chain reaction (PCR), next generation sequencing, or other CLIA-approved method;

AND

• FRα positive by central immunohistochemistry (IHC, Section 9.1). If archival tissue does not meet FRα criteria, a fresh biopsy tumor sample may be submitted and used to meet this criterium. If a fresh tumor biopsy cannot be done safely the patient will not be allowed to enroll on this study.

  • Participants must have measurable disease as defined by RECIST 1.1. Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions.
  • Prior therapy: Patients must have had one, but no more than three lines of chemotherapy for endometrial carcinoma.
• Prior hormonal therapy is allowed (no washout period is required after hormonal therapy) and does not count as a prior line of therapy. Hormonal therapy in combination with CDK4/6 inhibitors or mTOR or other PI3K-pathway inhibitors is allowed and does not count as a line of prior therapy.
• Prior IO therapy targeted to the PD-1/PD-L1 pathway is allowed in up to 19 patients of the total cohort.

• Patients must NOT have received prior therapy with any folate receptor ortholog agents.

  • Age 18 or greater years. Because insufficient dosing or adverse event data are currently available on the use of mirvetuximab soravtansine and pembrolizumab in participants <18 years of age, children are excluded. Endometrial cancer is rare in the pediatric population.
  • ECOG performance status 0 or 1
  • Participants must have normal organ and marrow function as defined below:
• leukocytes ≥3,000/mcL
• absolute neutrophil count ≥1,500/mcL
• platelets ≥100,000/mcL
• hemoglobin ≥ 9.0 g/dL
• total bilirubin ≤ 1.5 x institutional upper limit of normal
• AST(SGOT)/ALT(SGPT) ≤2.5 × institutional upper limit of normal
• creatinine ≤ institutional upper limit of normal OR

• creatinine clearance ≥40 mL/min/1.73 m2 for participants with creatinine levels above institutional normal.

  -Time from prior therapy:

• Systemic anti-neoplastic therapy: 5 half-lives or 4 weeks, whichever is shorter. Hormonal therapy is not considered anti-neoplastic therapy.

• Radiotherapy: wide-field radiotherapy (e.g. > 30% of marrow-bearing bones) completed at least 4 weeks, or focal radiation completed at least 2 weeks, prior to starting study treatment

  • The effects of agents used in this study on the developing human fetus are unknown. For this reason, women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, during study treatment, and for at least twelve weeks after the last dose of study treatment. Should a woman become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately.
  • Women of child-bearing potential must have a negative serum pregnancy test within 3 days prior to the first dose of study treatment.
  • Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

• Participants who have had chemotherapy within 5 half-lives or 4 weeks (whichever is shorter) or radiotherapy within 2 weeks prior to entering the study. Patients completing wide-field radiotherapy (e.g. >30% of marrow-bearing bones) must not have had treatment within 4 weeks prior to entering study. Participants must have recovered from all AEs due to previous therapy to Grade 1 ≤ or baseline, except alopecia. Participants with endocrine-related AEs who are adequately treated with hormone replacement are eligible.
• Participants who are receiving any other investigational agents.
• Participants with prior exposure to IO agents targeting the PD-1/PD-L1 pathway who discontinued therapy due to treatment-related toxicity deemed to be specifically related to IO therapy.
• Required use of folate-containing supplements (e.g. folate deficiency).
• Known active CNS metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate provided they are radiologically stable, i.e. without evidence of progression for at least 4 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 first dose of study treatment.
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to monoclonal antibodies (including antibody drug-conjugates or checkpoint inhibitors).
• Uncontrolled intercurrent illness including, but not limited to, any of the following within 6 months of first study treatment: symptomatic congestive heart failure, unstable angina pectoris, uncontrolled hypertension (≥ Grade 3), hypertensive crisis or hypertensive encephalopathy, uncontrolled cardiac arrhythmias, thrombotic or ischemic stroke, clinically-significant vascular disease (e.g. aortic aneurysm, or dissecting aneurysm), severe aortic stenosis, clinically significant peripheral vascular disease, or ≥ Grade 3 cardiac toxicity following prior chemotherapy, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
• Active or chronic corneal disorder, including but not limited to the following: Sjogren's syndrome, Fuchs corneal dystrophy (requiring treatment), history of corneal transplantation, active herpetic keratitis, and also active ocular conditions requiring on-going treatment/monitoring such as wet age-related macular degeneration requiring intravitreal injections, active diabetic retinopathy with macular edema, presence of papilledema, and acquired monocular vision.
• Serious clinically-relevant active infection, including known HIV infection, varicella-zoster virus, cytomegalovirus infection, has a known history of Hepatitis B (defined as Hepatitis B surface antigen [HBsAg] reactive) or known active Hepatitis C virus (defined as HCV RNA is detected) or any other known concurrent infectious disease requiring IV antibiotics with within 2 weeks of study enrollment are ineligible because of the potential for immune side effects.
• Has received a live vaccine within 30 days prior to the first dose of study drug. Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, varicella/zoster (chicken pox), yellow fever, rabies, Bacillus Calmette-Guérin (BCG), and typhoid vaccine. Seasonal influenza vaccines for injection are generally killed virus vaccines and are allowed; however, intranasal influenza vaccines (eg, FluMist®) are live attenuated vaccines and are not allowed.

• Current or prior use of immunosuppressive medication within 7 days prior to enrollment with the following exceptions to this exclusion criterion:

  • Intranasal, inhaled, topical steroids, or local steroid injections (eg, intra-articular injection);
  • Systemic corticosteroids at physiologic doses not to exceed 10 mg/day of prednisone or equivalent;
  • Steroids as premedication for hypersensitivity reactions (eg, CT scan premedication).
• Active autoimmune disease that might deteriorate when receiving an immunostimulatory agent. Patients with diabetes type I, vitiligo, psoriasis, hypo-or hyperthyroid disease not requiring immunosuppressive treatment are eligible.
• Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis.
• Pregnant or nursing women are excluded from this study because effects of agents used in this study on infants or the developing human fetus are unknown
• Presence of other malignancies unless they are considered cured by patient's oncologist

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: IMGN853 + Pembrolizumab; Pembrolizumab is administered intravenously once every 3 weeks; IMGN853 is administered intravenously once every 3 weeks	Drug: Pembrolizumab; Pembrolizumab is an immunotherapy that activates a patient's own immune system to recognize and kill tumor cells; Other Names: Keytruda; Drug: IMGN853; Mirvetuximab soravtansine is an antibody-drug conjugate.; Other Names: Mirvetuximab soravtansine; Elahere

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate	The objective response rate was determined by the frequency of patients who had objective tumor response, determined per Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1) for target lesions and assessed by CT or MRI, where objective response represents either a confirmed complete response (CR; disappearance of all target lesions) or a confirmed partial response (PR; at least a 30% decrease in the sum of the longest diameter of target lesions, taking as reference the baseline sum diameters); objective response = CR + PR. The ORR is therefore reported as the percentage of participants who achieved a CR or PR per RECIST v1.1.	6 months
Progression-Free Survival at 6 Months (PFS6)	Progression-free survival at 6 months was determined by the frequency of patients who survived progression-free for at least 6 months after initiating study treatment by Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1), where disease progression represents at least a 20% increase in the sum of diameters of target lesions, appearance of one or more new lesions, or unequivocal progression of existing non-target lesions.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall Survival	Overall survival (OS) is defined as the time from registration to death due to any cause, or censored at date last known alive. The distribution of overall survival times will be estimated using Kaplan-Meier analysis.	Participants are followed for survival status from registration through up to 3 years after removal from study intervention
Progression-free Survival	Progression-free survival was determined per Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1), where disease progression represents at least a 20% increase in the sum of diameters of target lesions, appearance of one or more new lesions, or unequivocal progression of existing non-target lesions. The distribution of progression-free times will be estimated using Kaplan-Meier analysis.	Interval from start of treatment to documented disease progression per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 or death from any cause, whichever occurs first.
Duration of Response	Duration of response (DoR) is defined as time from best overall response to the time of disease progression.	Interval from best overall response to documented disease progression per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 or death from any cause, whichever occurs first.

Collaborators and Investigators

• Sponsor: Dana-Farber Cancer Institute
• Collaborators: Merck Sharp & Dohme LLC; ImmunoGen, Inc.
• Investigators: Principal Investigator: Rebecca Porter, MD, PhD, Dana-Farber Cancer Institute

Study record dates

Study Major Dates

• Study Start (Actual): January 2, 2020
• Primary Completion (Actual): June 4, 2024
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: February 6, 2019
• First Submitted That Met QC Criteria: February 7, 2019
• First Posted (Actual): February 11, 2019

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Endometrial Cancer
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Uterine Diseases; Genital Diseases, Female; Genital Neoplasms, Female; Uterine Neoplasms; Endometrial Neoplasms; Antineoplastic Agents, Immunological; Immune Checkpoint Inhibitors; Antineoplastic Agents; Immunologic Factors; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Immunoconjugates; pembrolizumab; mirvetuximab soravtansine
• Other Study ID Numbers: 18-602

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The Dana-Farber / Harvard Cancer Center encourages and supports the responsible and ethical sharing of data from clinical trials. De-identified participant data from the final research dataset used in the published manuscript may only be shared under the terms of a Data Use Agreement. Requests may be directed to: [contact information for Sponsor Investigator or designee]. The protocol and statistical analysis plan will be made available on Clinicaltrials.gov only as required by federal regulation or as a condition of awards and agreements supporting the research
• IPD Sharing Time Frame: Data can be shared no earlier than 1 year following the date of publication
• IPD Sharing Access Criteria: BCH - Contact the Technology & Innovation Development Office at www.childrensinnovations.org or email TIDO@childrens.harvard.edu BIDMC - Contact the Beth Israel Deaconess Medical Center Technology Ventures Office at tvo@bidmc.harvard.edu BWH - Contact the Partners Innovations team at http://www.partners.org/innovation DFCI - Contact the Belfer Office for Dana-Farber Innovations (BODFI) at innovation@dfci.harvard.edu MGH - Contact the Partners Innovations team at http://www.partners.org/innovation
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No