Consider a clinical trial for your patients with advanced or recurrent mismatched repair proficient (pMMR) endometrial cancer. Connect with a clinical trial site to learn more and see if your patients may be eligible.

Symbiotic-GYN-18 is a Phase 3, open-label, randomized clinical trial for women with advanced or recurrent pMMR endometrial cancer. This study is evaluating the efficacy and safety of the study medicine, PF-08634404, in combination with chemotherapy versus the comparator drug (pembrolizumab) in combination with chemotherapy.

Randomization will be 1:1

  • PF-08634404 + carboplatin and paclitaxel, followed by maintenance PF-08634404
  • Pembrolizumab + carboplatin and paclitaxel, followed by maintenance pembrolizumab

Participants may receive the study treatment for about 2 years, until radiological disease progression, or until they are no longer deriving clinical benefit as assessed by the Investigator. After the study treatment ends, there will be an in-person end-of-treatment visit, and a follow-up visit or phone call every 12 weeks for assessment of survival and documentation of anticancer treatment.

To view all Symbiotic clinical trials, click here

About the study medicine

The study medicine, PF-08634404, is a bispecific antibody drug that was designed to target both PD-1 and VEGF. This dual mechanism has the potential to achieve tumor immunosurveillance, while disrupting vascular support for tumor progression, compared with blocking either target alone in patients with solid tumors.

Preliminary clinical data with PF-08634404 as monotherapy and combined with chemotherapy shows encouraging results in patients with metastatic colorectal cancer and non-small cell lung cancer.1-3

Key eligibility criteria

Key inclusion criteria

  • Female, aged 18 years or older
  • Histologically or cytologically proven endometrial cancer (EC) that is:
    • Newly diagnosed Stage III (with measurable disease)
    • Newly diagnosed Stage IV (with or without measurable disease)
    • Recurrent (with or without measurable disease), where the potential for cure by surgery ± radiotherapy and/or chemotherapy is poor
  • For patients with recurrent disease, prior adjuvant systemic anti-cancer treatment must be >6 months from date of relapse
  • Participants must be willing and able to provide tumor tissue for prospective central assessment of MMR and p53 status, and retrospective biomarker analysis. Biopsy must provide adequate tissue for MMR and p53 testing
  • MMR proficient (pMMR)
  • Carcinosarcomas are allowed

Key exclusion criteria

  • Pure sarcomas
  • dMMR EC
  • Systemic therapy for advanced or recurrent EC
  • Prior use of immunotherapy including anti-PD(L)-1 or systemic antiangiogenic therapy

Additional requirements apply. Only Principal Investigators can determine eligibility.

Study endpoints

Primary endpoint

  • PFS using RECIST v1.1 as assessed by BICR

Secondary endpoints

  • OS
  • PFS, ORR, and DoR by investigator

Safety endpoints

  • AEs as characterized by type, frequency, intensity as graded by NCI CTCAE version 5.0, timing, seriousness, and relationship to study intervention(s)
  • Laboratory test abnormalities as characterized by type, frequency, and severity (as graded by NCI CTCAE version 5.0)

Note: This is not a complete list of study endpoints.

  • AE, adverse event; BICR, blinded independent central review; CTCAE, Common Terminology Criteria for Adverse Events; DoR, duration of response; NCI, National Cancer Institute; ORR, objective response rate; OS, overall survival; PFS, progression-free survival; RECIST, Response Evaluation Criteria in Solid Tumors.

Together, we can make a difference

People are often introduced to clinical trials through conversations with their healthcare providers. We appreciate you taking the time to have discussions with your patients and their loved ones who may be interested in contributing to research.

Should any of your patients take part in this clinical trial, they will remain under your medical care for all non-study-related needs.

Thank you for considering your patients for this important clinical trial.

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References
  1. Xu X, Li W, Liu T, et al. 796P A phase II trial to evaluate the safety and efficacy of SSGJ-707: A bispecific antibody targeting PD-1 and VEGF, in combination with chemotherapy in patients with metastatic CRC. Ann Oncol. 2025;36:S508. doi:10.1016/j.annonc.2025.08.1369
  2. Wu L, Yao J, Sun Y, et al. A phase II trial to evaluate the safety and efficacy of SSGJ-707, a bispecific antibody targeting PD-1 and VEGF, as a monotherapy in patients with advanced NSCLC. J Clin Oncol. 2025;43(suppl 16):8543. doi:10.1200/JCO.2025.43.16_suppl.8543
  3. Wu L, Xu H, Sun Y, et al. 1328 SSGJ-707, a PD-1/VEGF bispecific antibody, combined with platinum-based chemotherapy in first-line treatment of advanced non-small cell lung cancer (NSCLC). Results from a phase 2 study. J Immunother Cancer. 2025:13(suppl 3):A1568-A1569. doi:10.1136/jitc-2025-SITC2025.1328