5.1 Hypersensitivity Reactions
Serious hypersensitivity reactions after administration of OXBRYTA have occurred in <1% of patients treated. Clinical manifestations may include generalized rash, urticaria, mild shortness of breath, mild facial swelling, and eosinophilia [see Adverse Reactions (6.1)].
Drug reaction with eosinophilia and systemic symptoms (DRESS) has been reported in postmarketing experience with OXBRYTA [see Adverse Reactions (6.2)]. Patients who develop a combination of skin rash, fever, peripheral eosinophilia, and internal systemic organ involvement (e.g., hepatic, renal, pulmonary) while receiving OXBRYTA should undergo medical evaluation.
Advise patients of the signs and symptoms of severe hypersensitivity reactions, including DRESS. If hypersensitivity reactions occur, discontinue OXBRYTA and administer appropriate medical therapy. Do not reinitiate OXBRYTA in patients who experience these symptoms with previous use.
5.2 Laboratory Test Interference
OXBRYTA administration may interfere with measurement of Hb subtypes (HbA, HbS, and HbF) by high-performance liquid chromatography (HPLC) [see Drug Interactions (7.3)]. If precise quantitation of Hb species is required, chromatography should be performed when the patient has not received OXBRYTA therapy in the immediately preceding 10 days.