for people ages 12 years and up (full criteria)
study started
estimated completion
Principal Investigator
by Gregory Daniels (ucsd)Deborah Jean Wong (ucla)Mili Arora (ucdavis)Hyunseok Kang (ucsf)Andrew Gianoukakis (ucla)
Photo of Gregory Daniels
Gregory Daniels
Photo of Hyunseok Kang
Hyunseok Kang



The reason for this study is to see if the study drug selpercatinib is safe and more effective compared to a standard treatment in participants with rearranged during transfection (RET)-mutant medullary thyroid cancer (MTC) that cannot be removed by surgery or has spread to other parts of the body. Participants who are assigned to the standard treatment and discontinue due to progressive disease have the option to potentially crossover to selpercatinib.

Official Title

A Multicenter, Randomized, Open-label, Phase 3 Trial Comparing Selpercatinib to Physicians Choice of Cabozantinib or Vandetanib in Patients With Progressive, Advanced, Kinase Inhibitor Naïve, RET-Mutant Medullary Thyroid Cancer (LIBRETTO-531)


Medullary Thyroid Cancer medullary thyroid carcinoma targeted therapy Thyroid Neoplasms Carcinoma, Neuroendocrine Thyroid Diseases Selpercatinib Cabozantinib Vandetanib


For people ages 12 years and up

  • At least 18 years of age (participants as young as 12 years of age will be allowed if permitted by local regulatory authorities).
  • Histologically or cytologically confirmed, unresectable, locally advanced and/or metastatic MTC and no prior history of treatment with kinase inhibitors for advanced/metastatic disease.
  • Radiographic progressive, measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 at screening compared with a previous image taken within the prior 14 months as assessed by central review.
  • A defined/acceptable RET gene alteration identified in a tumor, germline deoxyribonucleic acid (DNA) or blood sample.
  • Tumor tissue in sufficient quantity to allow for retrospective central analysis of RET mutation status
  • Eastern Cooperative Oncology Group performance status score of 0 to 2.
  • Adequate hematologic, hepatic, and renal function and electrolytes.
  • Men and women of childbearing potential must agree to use a highly effective contraceptive method during treatment with study drug and for 6 months following the last dose of study drug.
  • Ability to swallow capsules.

Exclusion Criteria:

  • An additional validated oncogenic driver in MTC if known that could cause resistance to selpercatinib treatment. Examples include, but are not limited to RAS or BRAF gene mutations and NTRK gene fusions.
  • Symptomatic central nervous system (CNS) metastases, leptomeningeal carcinomatosis, or untreated spinal cord compression.
  • Clinically significant active cardiovascular disease or history of myocardial infarction within 6 months, history of Torsades de pointes, or prolongation of the QTcF >470 milliseconds on more than one electrocardiogram (ECG) during screening. Participants who are intended to receive vandetanib if randomized to the control arm ineligible if QTcF is >450 milliseconds.
  • Active uncontrolled systemic bacterial, viral, or fungal infection or serious ongoing uncontrolled intercurrent illness.
  • Active hemorrhage or at significant risk for hemorrhage.
  • Other malignancy unless nonmelanoma skin cancer, carcinoma in situ of the cervix or malignancy diagnosed ≥2 years previously and not currently active. Participants with multiple endocrine neoplasia type 2 (MEN2) associated pheochromocytoma may be eligible.


  • University of California San Diego accepting new patients
    La Jolla California 92037 United States
  • UCLA Medical Center accepting new patients
    Los Angeles California 90095 United States
  • University of California, Davis - Health Systems accepting new patients
    Sacramento California 95817 United States
  • UCSF Medical Center at Mission Bay accepting new patients
    San Francisco California 94158 United States
  • Los Angeles Biomedical Research Institute at Harbor - UCLA Medical accepting new patients
    Torrance California 90502 United States

Lead Scientists at UC Cancer

  • Gregory Daniels (ucsd)
    Dr. Daniels coordinates our clinical program in melanoma. His own research involves understanding the link between autoimmunity and tumor immunity in developing more effective and less toxic vaccines and immune stimulatory approaches for patients with melanoma.
  • Deborah Jean Wong (ucla)
  • Mili Arora (ucdavis)
    Assistant Professor, Hematology and Oncology. Authored (or co-authored) 10 research publications.
  • Hyunseok Kang (ucsf)
    Dr.Hyunseok "Hyu" Kang is a medical oncologist and a clinician scientist focusing on head and neck cancers including squamous cell carcinomas of head and neck (SCCHN), salivary gland cancers, thyroid cancers and other rare cancers of head and neck.
  • Andrew Gianoukakis (ucla)


accepting new patients
Start Date
Completion Date
Eli Lilly and Company
A Study of Selpercatinib (LY3527723) in Participants With RET-Mutant Medullary Thyroid Cancer
Phase 3
Study Type
Last Updated