Cleveland BioLabs receives first U.S. patent allowance for its radiation protection drug, Protectan CBLB502

Cleveland BioLabs, Inc. announced recently that it has received a Notice of Allowance from the U.S. Patent and Trademark Office for its U.S. Patent Application Number 11/421,918, titled ‘Modulating Apoptosis’. Allowed claims cover the method of protecting a mammal from radiation using flagellin or its derivatives, including Protectan CBLB502.

This patent has already been granted by the nine member countries of the Eurasian Patent Organization and two additional countries. Cleveland BioLabs has filed 14 sets of patent applications in the USA and internationally, around various aspects and properties for CBLB502 and related Protectan compounds, including methods of use and composition of matter.

Yakov Kogan, Ph.D., MBA, the Chief Operating Officer of Cleveland BioLabs, noted, ’We are extremely pleased to be receiving this patent coverage. Protectan CBLB502 represents a completely novel approach to protection of healthy tissues from the impact of radiation and other acute stresses. We continue to pursue additional claims under this and other patent applications both in the U.S. and internationally’.

CBLB502 is a derivative of a microbial protein and has demonstrated the capacity to reduce injury from acute stresses, such as radiation and chemotherapy, in animal models. CBLB502 mobilizes several cell-protective mechanisms, including the inhibition of programmed cell death (apoptosis), the reduction of oxidative damage and the induction of regeneration-promoting cytokines.

CBLB502 is being developed under the U.S. Food and Drug Administration's Animal Efficacy Rule to treat Acute Radiation Syndrome (ARS) or radiation poisoning from any exposure to radiation, such as from a nuclear or radiological weapon or a nuclear accident. This approval pathway requires a demonstration of efficacy in representative animal models and safety and drug metabolism testing in healthy human volunteers.

Evidence of CBLB502's mechanism of action and activity in animal models was published in Science Magazine in April 2008 [1]. Data from 50 subjects in an initial Phase I safety and tolerability study indicated that CBLB502 was well tolerated and that normalized biomarker results corresponded to previously demonstrated activity in animal models of ARS. As part of the development of CBLB502, this study will be followed by a second, larger safety study in healthy human volunteers, which will be based on the results of the initial study. There is currently no FDA-approved medical countermeasure to treat ARS.

CBLB502 is also being developed as a supportive care measure to reduce and prevent the occurrence of side-effects of radiotherapy or chemotherapy in cancer treatment.


1 Burdelya, L.G. (2008) An agonist of toll-like receptor 5 has radioprotective activity in mouse and primate models. Science 320, 226–230

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