Nine in ten patients with advanced medullary thyroid cancer alive at three years on selpercatinib
In the international LIBRETTO-531 trial, presented at the ESMO 2026 congress by oncologist Jaume Capdevila of Vall d'Hebron Hospital and VHIO in Barcelona, 92% of patients with advanced medullary thyroid cancer and a RET gene mutation were alive at three years on selpercatinib, compared with 75% on standard drugs. The treatment is only for tumours with that mutation, and the trial is funded by drugmaker Eli Lilly.
At three years, 92 in every 100 patients were still alive. That is the figure oncologist Jaume Capdevila, of Vall d’Hebron University Hospital and the Vall d’Hebron Institute of Oncology (VHIO) in Barcelona, presented at the European Society for Medical Oncology congress (ESMO 2026) with the latest results of the LIBRETTO-531 trial.
The study compared selpercatinib, a targeted drug, with standard treatment in patients with advanced medullary thyroid cancer and a mutation in the RET gene, receiving their first treatment for the disease. It only works for tumours with that mutation. It is funded by Eli Lilly, which makes the drug.
193 patients against 98
In the trial, 193 patients received selpercatinib and 98 got their doctor’s choice of cabozantinib or vandetanib. After a median follow-up of almost four years, according to The ASCO Post:
- At three years, 92% were alive on selpercatinib versus 75% on the other drugs. At four years, 87.1% versus 66.8%.
- 75% had no disease progression at three years, versus 25%.
- 61% were still taking selpercatinib at the January 2026 data cutoff, compared with 9% in the other group.
Fewer people stopping because of side effects
Serious side effects occurred in both groups: grade 3 or higher in 69% of those on selpercatinib and 81% in the comparison group. But only 8% stopped selpercatinib because of them, against 32% who stopped the other drugs. The most common with selpercatinib were high blood pressure, dry mouth and diarrhoea.
«These results reinforce the importance of screening for RET alterations in patients with medullary thyroid carcinoma», Capdevila said. In other words: test the tumour’s genes to find out who can benefit.
