Although Humira will remain on ProAct’s preferred formulary at least until January 1, 2024, ProAct is continuing to monitor the biosimilar space as more Humira biosimilars launch to market this summer. The main two scenarios we are evaluating leading to January 1st include:
In both scenarios, we expect Humira plan spend to decrease in the coming years due to the introduction of competition. Based on recent settlement agreements, Stelara will be one of the next major drugs in the anti-inflammatory space to face biosimilar competition in early 2025. There are several manufacturers that may have biosimilar versions of both Humira and Stelara on the market in 2025, including Amgen and Teva, so we could see a manufacturer-specific biosimilar bundle in the future. Estimates show upwards of a 65% shift away from Stelara to biosimilars by 2027. Additional considerations for Stelara include several newer agents in the same class. These newer agents are designed to demonstrate superiority over Stelara in Crohn’s Disease, in which Stelara has the largest representation. Based on the studies' results, we could see a negative impact to Stelara utilization and transition to a newer agent.