USA – Bispecific Antibodies: FDA Drafts Guidance for Developers

With more than two dozen companies developing bispecific antibodies, the next frontier of cancer therapy may well involve these genetically engineered, recombinant antibodies, which is why the US Food and Drug Administration (FDA) on Thursday released new draft guidance to help developers of these products.

In explaining why bispecific antibodies could be advantageous, FDA notes that they “can target multiple disease-modifying molecules with one drug, with possible advantages over combination therapy or the use of antibody mixtures. The possibility of immune cell retargeting through the delivery of an effector or effector cell to a specific target or the possibility of synergistic efficacy through engagement of multiple targets gives bispecific antibodies the potential to advance the development of antibody-based therapies.”

Currently, only one bispecific antibody is marketed in the US: Amgen’s Blincyto (blinatumomab), which brought in $230 million in worldwide sales in 2018, up 31% from 2017. But others are coming, and recent safety concerns, such as a partial clinical hold initiated by FDA after Xencor reported two patient deaths from a Phase 1 study of a bispecific antibody in February, may have triggered the need for more FDA guidance.

“There are a number of challenges in developing bispecific antibodies, one of which may be significant immunogenicity caused by novel epitopes. This draft guidance addresses these considerations and provides recommendations regarding the type of data necessary to support the approval of bispecific antibodies,” FDA said…