Hemopure is a hemoglobin-based oxygen carrier (HBOC) ready for immediate infusion, that transports and delivers oxygen from the plasma and expands the circulating volume. The product is supplied in sterile, flexible infusion bags with a fill volume of 250mL. Consisting of 32.5 g purified, glutaraldehyde-polymerized, bovine hemoglobin (Hb) in an iso-oncotic balanced modified Ringer’s lactate, it can be stored at room temperature for at least three years.
Hemopure can be administered immediately and is compatible with all blood types; type and cross-match is unnecessary. It does not require warming or reconstitution prior to administration and can be administered through a standard intravenous line. Upon administration, it immediately transports oxygen to tissues served by blood flow and, because of the relatively small molecular diameter, has the potential of transporting oxygen through constricted or partially blocked blood vessels via the movement of plasma through tissues in which red blood cell (RBC) flow is restricted. Hemopure has an oxygen dissociation curve that is right-shifted with a P50 of 40 mmHg, compared to 27 mmHg for corpuscular hemoglobin. This property facilitates the uptake by and off-loading of oxygen from native red blood cells. When administered to anemic volunteers, Hemopure increased their pulmonary diffusion capacity, further demonstrating improved oxygen uptake. Furthermore, in a canine model, Hemopure was shown to enhance oxygen release in skeletal muscle . On a gram-for-gram basis, Hemopure was calculated to be approximately three times more potent than stored or fresh red blood cell hemoglobin at restoring baseline tissue oxygenation following severe acute anemia. It is important to realize, however, that the higher potency of Hemopure is realized only under conditions at which tissue oxygen utilization is near physiological limits (e.g., strenuous exercise) and there is sufficient oxygen content in the blood to allow for a rise in oxygen extraction from blood. The higher potency of Hemopure to oxygenate tissues cannot be realized if the blood oxygen content is low secondary to severe anemia. Under conditions of anemia, it is important to increase the oxygen carrying capacity of the blood by raising the total hemoglobin concentration.
In 2001, Hemopure was approved in South Africa for the treatment of adult surgical patients who are acutely anemic, for the purpose of eliminating, delaying, or reducing the need for allogeneic red blood cells. In 2010, Hemopure was also approved in the Russian Federation for the treatment of acute, all-cause anemia.
In the US, Hemopure is an investigational new drug that is not approved by the FDA as being safe or effective for any use in humans, and therefore only available through a clinical trial, or expanded access (sometimes called compassionate use). In recent years, Hemopure has been used extensively across the US under the FDA’s Expanded Access Program (EAP), to treat patients with severe, life-threatening anemia for whom blood transfusion is indicated, but not an option, and who have exhausted all other treatment options. Reasons for not being transfused could include unavailability of compatible blood, conditions when blood transfusions are contraindicated, and patient refusal due to religious beliefs.