UT Health San Antonio and Waseda University in Shinjuku, Japan have collaboratively developed a drug delivery system capable of delivering a cargo preferentially to bone marrow. This drug delivery system shows promise for therapeutic and diagnostic applications for which the cells of the bone marrow play an important role.
Background:
Targeted anti-cancer therapies and protectants for untransformed cells hold great promise for effective and safe anti-cancer treatments, but development of such targeted agents has suffered from lack of systems able to selectively or preferentially deliver active agents to transformed cells. As bone marrow is the site of hematopoiesis, a liposome able to carry encapsulated agents preferentially to bone marrow could have profound clinical implications for many applications, such as: 1) delivery of chemo- and radio-protecting agents to bone marrow to protect a patient’s hematopoietic function during radiation and chemotherapy treatment for solid tumors, 2) more specific delivery of agents to the bone marrow when the clinical goal is to ablate malignant bone marrow cells prior to bone marrow transplant, 3) the delivery of gene therapies to bone marrow, and 4) the delivery of anti-cancer drugs into bone marrow for the treatment of hematologic malignancies.
Commercial Application & Benefits:
Testing of this novel delivery system in non-human primates showed that 72% of an injected dose of the liposomes labeled with technetium-99m (99mTc) were found sequestered within the animals’ bone marrow at 3 hours post-injection, which increased slightly to 72.9% at 22 hours post-injection. The balance was distributed in the liver and spleen. This cargo-carrying liposome system is believed to be the first carrier system proven to be capable of delivering a high quantity of intravenously injected agents to bone marrow in a primate model, demonstrating the feasibility of its use for therapeutic, diagnostic and bone marrow-sparing (prophylactic) applications.
Studies were also performed using this novel bone marrow targeting system to deliver erythropoietin (EPO) in a rabbit renal anemia model. The studies show that bone marrow liposome targeted EPO (Lipo-EPO) resulted in significantly greater uptake of EPO in the bone marrow, and anemia improvement was shown to be greater in the Lipo-EPO group. If EPO can be efficiently delivered to bone marrow via such liposomes, enhanced efficacy and lower effective dose of EPO may be possible, potentially resulting in fewer side effects associated with EPO therapy.