A Study of Selpercatinib (LY3527723) in Participants With RET-Mutant Medullary Thyroid Cancer

Official Title

A Multicentre, 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)


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.

Trial Description

Primary Outcome:

  • Treatment Failure-Free Survival (TFFS) by Blinded Independent Committee Review (BICR)
Secondary Outcome:
  • Progression Free Survival (PFS) by BICR
  • Overall Response Rate (ORR): Percentage of Participants with Complete Response (CR) or Partial Response (PR) by BICR
  • Duration of Response (DoR) by BICR
  • Overall Survival (OS)
  • PFS2 by Investigator
  • Comparative Tolerability: Percentage of Time with High Side Effect Bother Based on the Functional Assessment of Cancer Therapy-Side Effects (FACT-GP5)
  • The Concordance of the Local Lab and the Central Lab RET Results: Percentage of Participants with RET-Positive Specimens as Called by the Central Lab, which is also RET-Positive as Called by a Local Lab (Positive Percent Agreement)

View this trial on ClinicalTrials.gov

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Canadian Cancer Society

These resources are provided in partnership with the Canadian Cancer Society