FDA approves selpercatinib, the first targeted therapy for young children with RET-altered thyroid cancer

Evidence stage: Later-Stage HumanRegulatory status: FDA-approved for the exact stated cancer/useGuideline status: Not addressed

The FDA granted accelerated approval to selpercatinib (Retevmo), an oral RET kinase inhibitor, for pediatric patients aged 2 and older with RET-altered metastatic thyroid cancer or other RET-altered solid tumors requiring systemic therapy — the first FDA approval of any targeted therapy specifically for pediatric patients under 12 with a RET alteration. The approval was based on LIBRETTO-121 (ClinicalTrials.gov NCT03899792), an international, single-arm, multicohort phase 1/2 trial; in the primary efficacy population of 25 patients aged 2 to 20 with locally advanced or metastatic RET-activated solid tumors that had not responded to available therapies, the confirmed objective response rate (by blinded independent review) was 48%. Selpercatinib works by blocking an overactive RET protein that certain thyroid cancers and other solid tumors depend on for growth.

What This Means

In the LIBRETTO-121 trial's primary efficacy population of 25 pediatric and young adult patients with RET-altered solid tumors (including RET-altered thyroid cancer) that had not responded to available therapies, selpercatinib produced a confirmed objective response, by blinded independent review, in 48% of patients — supporting the first FDA approval of any targeted therapy specifically for pediatric patients under 12 with a RET alteration.

What This Doesn't Mean

This is a single-arm trial with no randomized comparison group, the basis for an ACCELERATED approval, not a full/traditional approval — continued approval may depend on results from a confirmatory trial verifying clinical benefit. This record makes no claim about selpercatinib's effect on overall survival, which was not this trial's design.

Why It Matters

Targeted RET inhibitors had already shown strong activity in adults, but until this approval there was no FDA-approved targeted therapy specifically available to young children with a RET-altered solid tumor — a real, previously unaddressed treatment gap for this population, in a cancer type (thyroid) that had zero coverage on this site before this record.

Promise & Proof

Proof — strength of the evidence 5 / 5
  • Base score from evidence stage: Later-Stage Human.
  • FDA-approved for the exact stated cancer/use.
Promise — potential significance if later evidence holds up 3 / 5
  • Baseline — a validly-evidenced story starts here; every further point below is an explicit, checkable reason.
  • The record includes substantive editorial reasoning about why this discovery matters.
  • A distinct follow-on/confirmatory study or trial is already cited as a secondary source — the field is already building on this finding.

These two ratings are automatically computed from this story's own structured evidence fields and are shown separately on purpose — they are never combined into one score. They describe this record, not a medical recommendation: they do not establish medical certainty, do not substitute for reading the cited sources, and are recalculated whenever the underlying evidence changes.

Population / Applicability

Studied in: Patients aged 2 to 20 with locally advanced or metastatic RET-altered solid tumors (including RET-altered thyroid cancer) that had not responded to available therapies, enrolled in the primary efficacy population of the international, single-arm, multicohort, phase 1/2 LIBRETTO-121 trial. (Children / adolescents)

Restricted to patients with a confirmed RET alteration (biomarker testing required) whose disease has progressed on or is intolerant to prior therapy, or for whom no satisfactory alternative exists — not a first-line or universal pediatric-thyroid-cancer treatment. This record has not independently reviewed the full pediatric safety/tolerability profile, which should be added before publication given this is a therapy used in children.

Full evidence details
Study design
Non-randomized trial
Sample size
25

Funding & Conflicts

Sponsor/developer: Eli Lilly and Company (via its Loxo Oncology subsidiary) — not independently confirmed against a primary corporate-disclosure document.

Regulatory status by jurisdiction

United States (FDA)

Status
FDA-approved for the exact stated cancer/use
Indication
Pediatric patients aged 2 and older with RET-altered metastatic thyroid cancer, or other RET-altered solid tumors that are advanced or metastatic and require systemic therapy, that have progressed on or are intolerant to prior therapy, or for whom there is no satisfactory alternative treatment.
Biomarker requirement
RET gene alteration (fusion or mutation)
Decision date
2024-05-29
Source
Regulator record (opens in a new tab)

Guideline positions

Guideline

Position
Not addressed
Last verified
2026-08-13

Primary evidence supporting this story

Additional context

Why Should I Trust This?

  • 1 source at Tier 2 — Peer-reviewed primary research, trial registries, regulatory documents, official conference abstracts
  • Last reviewed: 2026-08-13

This panel summarizes real, checkable facts about this record's own sources and review status — it is not a trust score, and reading it is not a substitute for reading the cited sources yourself.

Discovery Timeline

Every recorded change to this record's content or publication status, in order.

  1. Status change — Status changed from "Legacy / Unverified" to "In editorial review".
  2. Status change — Status changed from "In editorial review" to "Verified".

Last reviewed

Related discoveries

FDA approves selpercatinib, the first targeted therapy for young children with RET-altered thyroid cancer

https://cancerdiscoveries.com/discoveries/fda-approves-selpercatinib-the-first-targeted-therapy-for-young-children-with-ret-altered-thyroid-cancer/

Evidence stage: Later-Stage Human

What This Means

In the LIBRETTO-121 trial's primary efficacy population of 25 pediatric and young adult patients with RET-altered solid tumors (including RET-altered thyroid cancer) that had not responded to available therapies, selpercatinib produced a confirmed objective response, by blinded independent review, in 48% of patients — supporting the first FDA approval of any targeted therapy specifically for pediatric patients under 12 with a RET alteration.

What This Doesn't Mean

This is a single-arm trial with no randomized comparison group, the basis for an ACCELERATED approval, not a full/traditional approval — continued approval may depend on results from a confirmatory trial verifying clinical benefit. This record makes no claim about selpercatinib's effect on overall survival, which was not this trial's design.

Why It Matters

Targeted RET inhibitors had already shown strong activity in adults, but until this approval there was no FDA-approved targeted therapy specifically available to young children with a RET-altered solid tumor — a real, previously unaddressed treatment gap for this population, in a cancer type (thyroid) that had zero coverage on this site before this record.

Primary sources

  • Safety and efficacy of selpercatinib in pediatric patients with RET-altered solid tumors: updated results from LIBRETTO-121 (Journal of Clinical Oncology, ASCO Annual Meeting) — https://doi.org/10.1200/JCO.2024.42.16_suppl.10022 (DOI 10.1200/JCO.2024.42.16_suppl.10022)

Date verified: 2026-08-13

Correction status: No correction or retraction