Merck (MRK) said late Wednesday the US Food and Drug Administration has approved Welireg to treat patients 12 years and older with locally advanced, unresectable, or metastatic pheochromocytoma or paraganglioma.

Pheochromocytoma and paraganglioma are rare tumors that come from the same tissue, the company said. The approval is based on data from the Litespark-015 study.