Four subjects (18.2%) reported at least one adverse event during selumetinib-only treatment (arthralgia, n = 1; diarrhea, n = 1; increased alanine aminotransferase, n = 1; pruritus, n = 1), and one subject (4.5%) reported at least one adverse event (erythema, n = 1) during selumetinib co-dosed with rifampicin. The gene discussed is GPT; the disease is Erythema.