Novartis announced that the US Food and Drug Administration (FDA) has granted crizanlizumab (SEG101) Therapy designation for the prevention of vaso-occlusive crises (VOCs) in patients of all genotypes with sickle cell disease (SCD). Also known as sickle cell pain crises, VOCs are unpredictable and extremely painful events that can lead to serious acute and chronic complications. VOCs happen when multiple blood cells stick to each other and to blood vessels, causing blockages. Treatments that make blood cells and blood vessels less sticky may help reduce the number of days patients experience VOCs. According to FDA guidelines, treatments that receive Breakthrough Therapy designation are those that treat a serious or life-threatening disease or condition and demonstrate a substantial improvement over existing therapies on one or more significant end points based on preliminary clinical evidence. The FDA granted Breakthrough Therapy designation for crizanlizumab based on positive results of the Phase II SUSTAIN trial, which compared the P-selectin inhibitor crizanlizumab with placebo in patients with sickle cell disease. SUSTAIN showed that crizanlizumab reduced the median annual rate of VOCs to health care visits by 45.3% compared to placebo (1.63 vs 2.98, P=0.010) in patients with or without hydroxyurea therapy. The study also demonstrated that crizanlizumab significantly increased the percentage of patients who did not experience any VOCs vs placebo (35.8% vs 16.9%, P=0.010) during treatment.