FDA Approves Nexus Pharmaceuticals' Methylene Blue Injection for Acquired Methemoglobinemia

• The FDA has approved Nexus Pharmaceuticals' Methylene Blue Injection, USP, for treating acquired methemoglobinemia, a rare blood disorder.
• Methylene Blue functions as an oxidation-reduction agent, converting the oxidized form of hemoglobin (Fe3+) to its reduced state (Fe2+), enhancing oxygen binding.
• The newly approved formulation will be available in single-dose vials, strengthening the supply of this critical medication for affected patients.
• Acquired methemoglobinemia can result from exposure to certain medications and leads to symptoms like cyanosis, headache, and shortness of breath.

Nexus Pharmaceuticals has received FDA approval for its Methylene Blue Injection, USP, indicated for the treatment of acquired methemoglobinemia (MetHb). This approval expands the therapeutic options available for managing this rare and serious blood disorder, ensuring a more robust supply of this essential medication.

Methemoglobinemia is characterized by elevated levels of methemoglobin in the blood, where hemoglobin's iron is in the ferric (Fe3+) state rather than the ferrous (Fe2+) state, impairing oxygen release to tissues. MetHb can be inherited or, more commonly, acquired through exposure to drugs like benzocaine, dapsone, or sulfonamides.

Mechanism of Action

Methylene Blue functions as an oxidation-reduction agent. In the context of methemoglobinemia, it helps to reduce the oxidized form of iron (Fe3+) in methemoglobin back to its reduced form (Fe2+) in hemoglobin. This action increases the oxygen-binding capacity of hemoglobin, thereby improving oxygen delivery to the body's tissues.

Clinical Implications

Symptoms of acquired MetHb include cyanosis (bluish skin discoloration), headache, giddiness, fatigue, and shortness of breath. In severe cases, it can lead to significant hypoxia and organ damage. Methylene Blue injection offers a therapeutic intervention to reverse these effects by restoring normal hemoglobin function.

Sridhar Desikan, Chief Scientific Officer at Nexus Pharmaceuticals, stated that the approval strengthens the supply of an AP-rated and TIAA compliant Methylene Blue Injection, emphasizing Nexus’s commitment to providing life-saving medicine.

Dosage and Availability

Methylene Blue Injection, USP, will be available in 50 mg/10 mL (5 mg/mL) (0.5%) single-dose vials, packaged in cartons of five. This formulation is designed for intravenous administration, allowing for rapid and effective treatment of severe MetHb.

Current Treatment Landscape

While other treatments like ascorbic acid, hyperbaric oxygen therapy, and red blood cell transfusions exist, Methylene Blue remains a primary therapeutic option for severe cases of acquired methemoglobinemia, highlighting the importance of this FDA approval in expanding access to a critical treatment.