UPDATED: Pfizer, Amgen prepare to dissolve Enbrel partnership

Pfizer ($PFE) and Amgen ($AMGN) are sorting out responsibilities, and people, over Enbrel, as it unwinds a North American marketing agreement. Amgen is taking on promotion for the blockbuster anti-inflammatory drug.

Starting July 23, Amgen assumes field sales activities in the U.S. and Puerto Rico, but not Canada, the companies told The Wall Street Journal.

It is unclear where that leaves Pfizer reps assigned to Enbrel. They can apply for other Pfizer jobs or to work for Amgen promoting Enbrel, a spokeswoman says. The co-promotion deal expires Oct. 31, 2013.

Pfizer is about to introduce a competing drug, tofacitinib. The FDA is reviewing Pfizer's application to market tofacitinib to treat rheumatoid arthritis, with a decision expected in August.

"The unified Amgen sales force allows Amgen and Pfizer to ensure continuity in customer service during the transition time," an Amgen spokeswoman told the WSJ.

- here's the WSJ story