As part of the amended deal, certain existing milestones and funding obligations have been revised, and the deal has been expanded to include select pre-commercialization activities.
In total, the revised milestone payments may exceed the previous Baxter funding obligations by about $12m.
In addition, Baxter has agreed to purchase Coherus common stock in a private placement transaction.
Coherus president and chief executive officer Denny Lanfear said: "We are pleased that Baxter, a premier healthcare company, has reinforced its commitment to our collaboration.
"This amendment further aligns our shared interest in bringing high quality biosimilar therapeutics to patients around the world."
According to the companies, all other contractual provisions remain materially unchanged.
Baxter BioScience global head of biosimilars Dagmar Rosa-Bjorkeson said: "With this amended agreement, we will continue to advance development of the etanercept biosimilar program and begin preparations for eventual commercialization in Europe."