The following is a summary of a press release from Catalyst Biosciences by Dr. Robert Sidonio, a trusted medical advisor. Read the full press release here.
On June 18, Catalyst Biosciences provided an update of the progress from its Phase ½ trial investigating the use of FIX variant product, called CB 2679d/ISU304, which is a high-potency recombinant FIX product that can be given by IV and subcutaneous (under the skin – also known as SQ). This product has been enhanced (select mutations) in multiple ways to be more effective than standard FIX products:
- Altered to resist inhibition by our body’s natural inhibitor called Anti-thrombin (ATIII)
- Altered to have increased affinity (better binding) for FVIIIa (combine better with FVIIIa)
- Altered to generate more efficient clotting activity
Because of these changes, it can be given under the skin and achieve hemostatic levels of FIX in the blood with a longer half-life. This has been successfully demonstrated in dogs.
In a select group which required a single IV dose followed by daily SQ doses times nine days of the aforementioned drug, the human patient was able to achieve a FIX level of 20 percent after the IV loading dose and levels of 31 to 34 percent after the SQ doses.
This early interim data demonstrates this drug is able to achieve mild FIX deficiency levels ( approximately 30 percent) after SQ administration. There was demonstration of a transient antibody in one patient and neutralizing antibody in another patient. This antibody neutralized the FIX product but not the native FIX nor infused other FIX products. They are now investigating the cause and nature of the neutralizing antibodies to prevent this from occurring again.
Read the full press release here.