It should be possible to import DXB drawing to Autodesk AutoCAD and save it in its own, default, DWG file format.
Convert AutoCAD drawing exchange format to AutoCAD drawing.
We found 2 software records in the database related to .dxb to .dwg file format conversion.
Microsoft Windows software - convert dxb to dwg on Windows
Leading 2D and 3D CAD development software from Autodesk
Convert from dxb file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned dxb to dwg. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert dxb to dwg on OS X
Mac version of popular Autodesk AutoCAD software