Grifols has received approval from the FDA for a new higher potency formulation of its rabies immune globulin (human) (HyperRAB) for rabies post-exposure prophylaxis.

The product is administered immediately after a person is exposed to the rabies virus. The new formulation is twice the potency (300 IU/mL) of currently available rabies immune globulin options, offering a greater concentration of anti–rabies virus antibodies within each milliliter of volume, and for patients, the potential for fewer injections by significantly reducing the volume of medication administered in each dose, Grifols noted in a press release.

“This is the first advancement in administration of human rabies immune globulin (HRIG) treatment in over 40 years,” Charles Rupprecht, VMD, MS, PhD, an expert technical advisor on rabies for the Pan American Health Organization/World Health Organization (PAHO/WHO), and the former chief of the rabies program at the CDC, stated in the press release.

“Because patients are required to be dosed by weight, the increased potency of this new formulation allows more rabies antibodies per mL to go directly into wounds in delicate areas, such as the extremities or face," Dr. Rupprecht said. "Administration in these areas has proven to be very uncomfortable for patients, especially children, and challenging for healthcare professionals in administration of the full dose.”

Approximately 60,000 people in the United States each year are treated with post-exposure prophylaxis following exposure to an animal that is known, or thought, to have rabies. For patients who have not been vaccinated before, the Advisory Committee on Immunization Practices and the CDC recommend immediate prophylaxis following exposure to rabies, including a rabies immune globulin injection directly into the wound site to prevent the virus from entering the central nervous system, which eventually leads to death.

“Since the launch of the first version of HyperRAB 40 years ago, nearly a million patients worldwide have received treatment with this product to decrease risks associated with rabies exposure,” stated Bill Zabel, the president of Grifols North America Sales and Commercial Operations. “With HyperRAB now available in a 300 IU/mL strength, physicians can significantly reduce the volume of medication delivered in each dose, which is the single biggest challenge today. This new formulation increases the long-standing confidence physicians have in what Grifols’ rabies immune globulin treatment can deliver to patients who need protection from a condition that is essentially 100 percent fatal.”

Rabies immune globulin will now be available to U.S. patients in two sizes (1 mL/300 IU and 5 mL/1500 IU), according to Grifols. This new formulation is manufactured using a sophisticated caprylate–chromatography process, which significantly reduces procoagulant activity and product impurities, such as IgG aggregates, the company noted. This product is manufactured according to the highest quality and safety standards and includes labeling for prion removal. Grifols plans to expand its vial size offerings in the coming months.

Indications and Usage
Rabies immune globulin is indicated for post-exposure prophylaxis, along with rabies vaccine, for all persons suspected of exposure to rabies, except persons who have been previously immunized with rabies vaccine and have a confirmed adequate rabies antibody titer, who should receive only vaccine.
Evaluate the risks of contracting rabies infection. Consult with local or state public health officials if questions arise about the need for rabies prophylaxis.

Limitations of Use
• For unvaccinated persons, the combination of rabies immune globulin and vaccine is recommended for both bite and nonbite exposures, regardless of the time interval between exposure and initiation of post-exposure prophylaxis.
• Beyond day 7 after administering rabies vaccine, rabies immune globulin is not indicated, because an antibody response to vaccine is presumed to have occurred.

Important Safety Information
• Administer HyperRAB cautiously to patients with a history of prior systemic allergic reactions following the administration of human immunoglobulin preparations. Have epinephrine available for treatment of acute allergic symptoms, should they occur.
• Weigh the benefits of administering HyperRAB to persons with isolated immunoglobulin A (IgA) deficiency against the potential risks of hypersensitivity reactions. Such persons have increased potential for developing antibodies to IgA and could have anaphylactic reactions to subsequent administration of blood products that contain IgA.
• Inject intramuscularly only. Do not administer HyperRAB intravenously because of the potential for serious reactions. Do not inject into a blood vessel.
• As with all preparations administered by the intramuscular route, bleeding complications may be encountered in patients with thrombocytopenia or other bleeding disorders.
• HyperRAB is made from human blood and may carry a risk of transmitting infectious agents, eg, viruses, the variant Creutzfeldt-Jakob disease (vCJD) agent, and, theoretically, the Creutzfeldt-Jakob disease (CJD) agent.
• The most common adverse reactions during clinical trials were injection-site pain and headache.

Grifols encouraged clinicians to review the full prescribing information for rabies immune globulin.