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Closed (no longer recruiting)Last updated: 17 May 2024

LIBRETTO-121: This phase I/II trial is testing a new oral cancer drug (LOXO-292) for the treatment of children that have advanced solid- or primary central nervous system- cancerA Phase 1/2 Study of the Oral RET Inhibitor LOXO 292 in Pediatric Patients With Advanced RET-Altered Solid or Primary Central Nervous System Tumors

Clinical summary


This study includes 2 parts: phase 1 (dose escalation) and phase 2 (dose expansion). In phase 1, eligible patients will be enrolled using a rolling 6 dose escalation scheme, with the starting dose of LOXO-292 being 160mg, twice daily (. equivalent to an adult recommended phase 2 dose). Once maximum tolerated dose or recommended phase 2 dose is identified in phase 1 of this trial, patients will be enrolled to one of four phase 2 dose expansion cohorts, depending on tumour histology and genotype. The cycle length for both phase 1 and phase 2 will be 28 days.


This trial is treating patients with advanced solid cancer or a primary cancer of the central nervous system (CNS)


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Trial Acronym


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Trial Identifiers

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Trial sponsor

Loxo Oncology, Inc.

Scientific Title

A Phase 1/2 Study of the Oral RET Inhibitor LOXO 292 in Pediatric Patients With Advanced RET-Altered Solid or Primary Central Nervous System Tumors



  • Advanced or metastatic solid or primary CNS tumor which has failed standard of care therapies
  • Evidence of an activating RET gene alteration in the tumor and/or blood
  • Measurable or non-measurable disease
  • Karnofsky (participants 16 years and older) or Lansky (participants younger than 16) performance score of at least 50
  • Participant with primary CNS tumors or cerebral metastases must be neurologically stable for 7 days prior and must not have required increasing doses of steroids within the last 7 days
  • Adequate hematologic, hepatic and renal function.
  • Ability to receive study drug therapy orally or via gastric access
  • Willingness of men and women of reproductive potential to observe conventional and effective birth control


  • Major surgery within two weeks prior to planned start of LOXO-292
  • Clinically significant, uncontrolled cardiac, cardiovascular disease or history of myocardial infarction within 6 months prior to planned start of LOXO-292
  • Active uncontrolled systemic bacterial, viral, fungal or parasitic infection
  • Clinically significant active malabsorption syndrome
  • Pregnancy or lactation
  • Uncontrolled symptomatic hyperthyroidism or hypothyroidism (i.e. the participant required a modification to current thyroid medication in the 7 days before start of LOXO-292)
  • Uncontrolled symptomatic hypercalcemia or hypocalcemia
  • Known hypersensitivity to any of the components of the investigational agent, LOXO-292 or Ora-Sweet® SF and OraPlus®, for participants who will receive LOXO-292 suspension
  • Prior treatment with a selective RET inhibitor(s) (including investigational selective RET inhibitor[s])


  • You have had treatment but your cancer has gotten worse or has not responded to the treatment you have been given.
  • You are able to swallow medication by mouth.


  • You have certain types of non-cancer medical conditions.
  • You have had certain treatments, surgical procedures or drugs.

Clinical trials have complex eligibility criteria.

Ask your doctor if this trial could be right for you.

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