Two affiliated Chinese drug manufacturers targeted by forthcoming US national security legislation are working on sales of some of their operations, according to people familiar with the matter.

WuXi AppTec and WuXi Biologics are among five China-based companies targeted by the Biosecure Act, which would ban drugmakers with US government contracts from using the Chinese groups’ services after 2032. The bipartisan bill overwhelmingly passed the House of Representatives last month and is making its way through the Senate.

WuXi AppTec has put its cell and gene therapy manufacturing arm WuXi Advanced Therapies, which operates four laboratories and manufacturing facilities in Philadelphia, up for sale, according to three people familiar with the matter. Discussions have been ongoing for months and rival contract manufacturers have been approached about buying all or some of the assets.