Sickle Cell Disease: Advances in Treatment

Abstract

Background: Sickle cell disease causes significant morbidity and mortality and affects the economic and healthcare status of many countries. Yet historically, the disease has not had commensurate outlays of funds that have been aimed at research and development of drugs and treatment procedures for other diseases. Methods: This review examines several treatment modalities and new drugs developed since the late 1990s that have been used to improve outcomes for patients with sickle cell disease. Results: Targeted therapies based upon the pathophysiologic mechanisms of sickle cell disease that result in organ dysfunction and painful episodes include hydroxyurea, L-glutamine, crizanlizumab, and other drugs that are currently on the market or are on the verge of becoming available. These agents have the potential to improve survival and quality of life for individuals with sickle cell disease. Also discussed is stem cell transplantation that, to date, is the only curative approach for this disease, as well as the current status of gene therapy. Conclusion:These examples demonstrate how the current knowledge of sickle cell disease pathophysiology and treatment approaches intersect. Although interest in sickle cell research has blossomed, many more clinical trials need to be initiated and subjected to more strenuous examination and analysis than have been used in the past.

Rational Drug Design of Peptide-Based Therapies for Sickle Cell Disease

“…These notwithstanding, the need for new therapeutic approaches remains high and one of the recent efforts includes developments aimed at inhibiting the polymerization of hemoglobin S. This review focuses on anti-sickling approaches using peptide-based inhibitors, ranging from individual amino acid dipeptides investigated 30-40 years ago up to more promising 12-and 15-mers under consideration in recent years.Molecules 2019, 24, 4551 2 of 23 with hemoglobin reduces HbS solubility and promotes polymerization, also called sickling [3,4]. This ultimately leads to hampered O 2 binding and transport, impaired erythrocyte morphology and interaction with endothelial surfaces [5,6], premature erythrocyte rupture and anemia, painful vaso-occlusive crisis, a general poor health, and, in many cases, death [7][8][9][10][11].Despite growing understanding of the polymerization of HbS and its effects on red blood cells (RBCs), until very recently, only two drugs-hydroxyurea and L-glutamine-were approved by the United States (US) Food and Drug Administration (FDA) for the management of SCD [12]. Hydroxyurea is the most widely employed drug treatment of sickle cell anemia in different age groups [13][14][15][16][17][18].…”

“…There have, however, been certain reports of associated malignancies [27][28][29][30][31][32], but further investigations are needed to categorically confirm these [33]. L-glutamine is the second approved drug treatment [12,34]. While its mechanism of action is not known, and only suggested to involve a reduction of oxidative stress via elevation of the levels of reduced glutathione [35,36], it is clear that it has no effect on hemoglobin S aggregation and hemoglobin production [37][38][39][40][41].…”

“…Of the millions of people with SCD, more than 75% are believed to live in Nigeria, Democratic Republic of Congo, and India [5,48,49]. These countries are additionally responsible for about 80% of global newborns having the causative Glu6 to Val6 mutation [50].Recent reviews described different treatment modalities and efforts to develop new drugs targeting SCD [12,51,52]. A number of research attempts have been made to design interventions aimed at modulating the structural properties, aggregation tendencies, and defective O 2 transport properties of sickle hemoglobin.…”

“…Despite growing understanding of the polymerization of HbS and its effects on red blood cells (RBCs), until very recently, only two drugs-hydroxyurea and L-glutamine-were approved by the United States (US) Food and Drug Administration (FDA) for the management of SCD [12]. Hydroxyurea is the most widely employed drug treatment of sickle cell anemia in different age groups [13][14][15][16][17][18].…”

“…Recent reviews described different treatment modalities and efforts to develop new drugs targeting SCD [12,51,52]. A number of research attempts have been made to design interventions aimed at modulating the structural properties, aggregation tendencies, and defective O 2 transport properties of sickle hemoglobin.…”