Selpercatinib Gets Traditional FDA Approval for RET Fusion Solid Tumors

What the FDA did on July 14, 2026

The FDA gave full approval to selpercatinib, sold as Retevmo. It covers adults and children aged 2 and older. Their tumor must be a solid tumor that is locally advanced or has spread. And it must carry a RET gene fusion, found by an FDA-approved test.

Two more conditions apply. The disease must have grown on or after earlier drug treatment. Or there must be no good alternative left.

The drug already held accelerated approval for this use. That came in 2022 for adults and 2024 for children. This action converted it to full approval.

Accelerated versus traditional approval

These are two different bars, and the difference is worth understanding.

Accelerated approval lets a drug reach patients early. It rests on a first signal, usually how many tumors shrank. The benefit is speed. The catch is that shrinkage is a stand-in for what matters. The maker has to keep collecting evidence.

Full approval means the FDA has accepted the wider evidence. The drug is no longer on probation.

Some accelerated approvals never convert. They get pulled instead, when the later data do not hold up. That is the system working. It is also why this conversion counts as news.

What a RET fusion is

Genes sit on chromosomes in order. Sometimes a chromosome breaks and rejoins in the wrong place. That can splice two unrelated genes together. The result is a fusion gene, and it makes a hybrid protein.

RET codes for a receptor. It normally passes growth signals into a cell under tight control. When RET is fused to a partner gene, that control is lost. The hybrid protein is stuck on. The cell keeps hearing a grow signal.

Selpercatinib blocks the RET protein. If the fusion is driving the tumor, blocking it can shut the tumor down. Where the tumor started does not matter.

One distinction is easy to miss. A RET fusion is not the same as a RET point mutation. Point mutations show up in medullary thyroid cancer. That is a different situation with different evidence. The report has to say fusion.

The evidence behind it

The evidence came from a trial called LIBRETTO-001. It was open-label and ran many cohorts at many sites. Results in RET fusion lung and thyroid cancer backed it up.

The tumor-agnostic part rested on 75 patients. Their tumors were not lung or thyroid cancer. All had grown on earlier treatment, or had no good option left.

The response rate was 47%. The 95% confidence interval ran from 35% to 59%. Responses lasted a median of 24.5 months.

The tumor types that responded show how scattered these fusions are. They included bowel, pancreas, salivary gland, and soft tissue sarcoma. They also included bile duct, skin, breast, ovary, and small bowel tumors. Some had no known primary site.

In children, evidence came from a second trial, LIBRETTO-121. Responses were seen in a child with infantile fibrosarcoma, one with a spindle cell sarcoma, and in thyroid cancer.

Side effects and monitoring

The label lists a long set of warnings. They include liver damage, lung inflammation, and high blood pressure. They also include a heart rhythm change called QT prolongation. Bleeding, allergic reactions, and tumor lysis syndrome are on the list too. So are poor wound healing, an underactive thyroid, and harm to a fetus.

Children carry one more warning. It is a hip growth-plate problem called slipped capital femoral epiphysis.

Dosing goes by weight for people aged 12 and over. Under 50 kg it is 120 mg twice a day. At 50 kg or above it is 160 mg twice a day. The weight bands are the label's starting point. A doctor still sets the amount for each person.

Because the amount depends on your weight, it is worked out for you individually. Take what your own prescription says rather than reading it off this page.

When to raise this with a team

There is no screening test for a RET fusion. This is entirely a question of whether testing was done.

Ask about it if any of the following apply:

• You have an advanced solid tumor and standard options are narrowing.
• Your tumor has never had broad next-generation sequencing, only a small targeted panel.
• Sequencing was done years ago, before fusion detection was routine.
• Your report mentions RET but does not clearly say whether the change is a fusion.
• The diagnosis is a rare tumor type, or a cancer of unknown primary.

Ask two direct questions. Was my tumor tested for gene fusions? And does the report distinguish a fusion from another kind of RET change?

NCI notes how the fusions were found in the trial. Certified labs used next-generation sequencing, fluorescence in situ hybridization, or a PCR assay. Our page on biomarker testing explains what those reports contain. Our page on how targeted therapy works covers the idea behind them.

What this does not mean

• It does not mean selpercatinib treats all solid tumors. The fusion is the entry requirement.
• It does not mean tumor type stops mattering. Stage, prior treatment, symptoms and other features still shape the plan.
• It does not mean every RET change qualifies. A fusion is not a point mutation.
• Response rate is not survival. Just under half of a small group responded.
• It does not remove the need to weigh side effects, monitoring, drug interactions, and coverage.

Why headlines mislead here

A phrase like "approved for solid tumors" sounds like it covers everyone with cancer. The real label is one of the narrowest in cancer medicine. It needs a specific gene change, found by an approved test, in someone who has already tried other options.

The useful takeaway is not the drug. It is the testing. A tumor-agnostic approval is worth nothing to a person whose tumor was never sequenced.

Sources

• FDA grants traditional approval to selpercatinib for locally advanced or metastatic RET fusion-positive solid tumors
• FDA: Oncology (Cancer)/Hematologic Malignancies Approval Notifications
• NCI PDQ: Agnostic Cancer Therapies (Health Professional Version)
• NCI: Biomarker Testing for Cancer Treatment

How this page was made

An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.

Cancer Explained is published by the National Cancer Information Foundation. It is not medical advice and does not suggest a test or treatment.

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