Ten-year-old Leo had already beaten brain cancer once. Then, years after radiation saved his life, a new tumor appeared — cruelly, in the same area. Doctors called it a radiation-induced glioma. These tumors are rare, aggressive, and nearly always fatal.
Brain tumors caused by past radiation are a tragic twist of fate. They often appear in survivors of childhood cancers like medulloblastoma. Standard treatments — more radiation, chemo — rarely work well. Most kids live less than nine months after diagnosis. Families face heartbreaking choices with few real options.
Now, a new clue is offering a sliver of hope. A drug called capmatinib — originally approved for lung cancer — is showing unexpected power against these tumors. But only in a specific group: children whose tumors carry a rare genetic switch called a MET fusion.
This doesn’t mean this treatment is available yet.
The MET fusion acts like a stuck accelerator in brain cells. Normally, cell growth is tightly controlled — like traffic with stoplights and speed limits. But when MET fuses with another gene, it’s like cutting the brake lines. Cells grow nonstop, forming a tumor. Capmatinib works by slamming the brakes back on.
What makes this drug different is its ability to reach the brain. Many cancer drugs fail because they can’t cross the blood-brain barrier — a protective filter. Capmatinib slips through. It targets the faulty MET protein directly, like a key fitting into a broken lock.
In a recent report, two children with MET-fusion brain tumors received capmatinib after surgery and re-radiation. Both had been treated for medulloblastoma as younger kids. Now, facing a second brain tumor, they had no standard options left. Doctors prescribed capmatinib off-label — meaning it wasn’t approved for this use, but the genetics matched.
The results were striking — at first. MRI scans showed tumors shrinking by more than half in both kids. That’s called a partial response, and it’s rare in these cases. One child lived 11 months after diagnosis, the other 15. That’s longer than the typical nine months seen in similar cases.
But the tumors came back. Despite the initial success, resistance developed quickly. The cancer found a way around the drug, like a detour around a roadblock. Both children eventually worsened.
Why the response didn’t last is still unclear. But the fact that the drug worked at all is significant. It proves that targeting MET can slow these tumors — even in the brain. And it confirms that capmatinib can reach its target where many drugs fail.
Experts say this is a step toward smarter, more personalized treatment. Instead of treating all brain tumors the same, doctors can now look for specific genetic flaws. MET fusions may be rare, but when found, they offer a clear target. Data from the Open Pediatric Brain Tumor Atlas suggest these fusions are more common in radiation-induced tumors than in other gliomas.
For families today, this means genetic testing is more important than ever. If a child develops a brain tumor after radiation, testing for MET, NTRK, and other fusions could open new doors. Capmatinib isn’t a cure, but it may buy precious time — and a chance for better treatments down the road.
Still, this was only two patients. The drug hasn’t been tested in large trials for this use. Side effects were mild — just some swelling in the limbs — but long-term safety isn’t known. And not every child will have the MET fusion.
The next step is clear: test capmatinib earlier, and combine it with other drugs to delay resistance. Researchers are already exploring combinations that could block escape routes in cancer cells. Clinical trials are needed to find the right mix, the right dose, and the best timing.
For now, this story is one of cautious hope. A drug designed for adults with lung cancer is helping children in desperate need. It’s not the end of the road — but it’s a sign that progress is possible, even in the toughest cases.