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A Study of SY 5609, a Selective CDK7 Inhibitor, in Advanced Solid Tumors

Trial Status: Active

This is a dose escalation study and will be the first to administer SY-5609 alone to humans with select advanced solid tumors and in combination with Fulvestrant to patients with HR positive, HER2-negative breast cancer.

Inclusion Criteria

  • Age ≥ 18 years
  • Advanced Solid Tumors for which standard curative or palliative measures do not exist or are no longer effective (Group 1 only).
  • Postmenopausal women with HR-positive, HER2-negative advanced or metastatic breast cancer. Patients must have failed prior treatment with a CDK 4/6 inhibitor in combination with hormonal therapy in a previous line of therapy (Group 2 only).
  • Patients must have at least one (1) measurable lesion by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1.
  • All toxicities (except alopecia) from prior cancer treatments must have resolved to ≤ Grade 1 before enrollment.
  • For women of childbearing potential (WCBP): negative serum β human chorionic gonadotropin pregnancy test within 1 week before the first dose of SY 5609
  • Adequate organ and marrow function
  • Patients must be willing and able to comply with all aspects of the protocol
  • Patients must provide written informed consent before any study-specific screening procedures

Exclusion Criteria

  • Chemotherapy or limited field radiotherapy within two (2) weeks, wide field radiotherapy within four (4) weeks, or nitrosoureas or mitomycin C within six (6) weeks before entering the study
  • Major surgery within two (2) weeks before starting the study treatment, or not recovered to baseline status from the effects of surgery received > two (2) weeks prior
  • Received any other investigational agents within 4 weeks before enrollment, or < five (5) half-lives since completion of previous investigational therapy, whichever is shorter
  • Received previous noncytotoxic, US Food and Drug Administration-approved anticancer agent within previous two (2) weeks, or < five (5) half-lives since completion of previous therapy, whichever is shorter
  • Known brain metastases or carcinomatous meningitis
  • Immunocompromised patients with increased risk of opportunistic infections
  • Patients with known active or chronic hepatitis B or active hepatitis C infection. Patients with a history of hepatitis C virus (HCV) infection who have completed curative therapy for HCV at least 12 weeks before Screening and have a documented undetectable viral load at Screening are eligible for enrollment.
  • Baseline QT interval corrected (QTc) with Fridericia's method > 480 ms
  • NOTE: criterion does not apply to patients with a right or left bundle branch block (QTc interval)
  • Female patients who are pregnant or breastfeeding
  • History of clinically significant cardiac disease or clinically relevant uncontrolled cardiac risk factors
  • Uncontrolled intercurrent illness


Emory University Hospital / Winship Cancer Institute


Brigham and Women's Hospital
Status: ACTIVE
Dana-Farber Cancer Institute
Status: ACTIVE
Massachusetts General Hospital Cancer Center
Status: ACTIVE


Oklahoma City
University of Oklahoma Health Sciences Center
Status: ACTIVE


Thomas Jefferson University Hospital
Status: ACTIVE

Trial Phase Phase I

Trial Type Treatment

Lead Organization
Syros Pharmaceuticals

  • Primary ID SY-5609-101
  • Secondary IDs NCI-2020-03935
  • ID NCT04247126