SDHB and gastrointestinal stromal tumor: In the SDH-deficient GIST group, with a median (range) follow-up of 17.0 (4.1–57.5) months, 6 of 26 (23.1%) evaluable patients experienced a confirmed PR per RECIST v1.1 (objective response rate, 23.1%; 95% confidence interval [CI], 9–43.7); an additional 16 patients (61.5%) did not progress during the first 6 months of treatment.