Answer
It is the form named in the product composition; bortezomib is the clinically active proteasome inhibitor.
Sources for this answer
- Bortezomib Biotech Pharma Limited 3.5 mg powder for solution for injection — Current selected SmPCemc · Summary of Product Characteristics
- Bortezomib 2.5mg/ml Solution for Injection (3.5mg total content) — Current selected SmPCemc · Summary of Product Characteristics