A Study of Oral LOXO-292 (Selpercatinib) in Pediatric Participants With Advanced Solid or Primary Central Nervous System (CNS) Tumors

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

This is an open-label, multi-center Phase 1/2 study of oral LOXO-292 in pediatric participants with an activating rearranged during transfection (RET) alteration and an advanced solid or primary CNS tumor.

This study includes 2 parts: phase 1 (dose escalation) and phase 2 (dose expansion). In phase 1, participants will be enrolled using a rolling 6 dose escalation scheme. The starting dose of LOXO-292 is equivalent to the adult recommended phase 2 dose of 160 milligrams (mg) twice a day (BID). Once the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) is identified, participants will be enrolled to one of four phase 2 dose expansion cohorts depending on tumor histology and tumor genotype. Cycle length will be 28 days.

Inclusion Criteria:

• 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

Exclusion Criteria:

• 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])