AbbVie Inc’s (NYSE:ABBV) top-selling arthritis drug, Humira, has managed to retain over 80% of its patients even after facing nine lower-priced rivals in the U.S. over the past year, Reuters reports. This raises concerns among drug pricing experts and analysts about the sustainability of the biosimilar market in its current form. Humira, priced at nearly $7,000 per month, is the first high-selling drug to compete with numerous biosimilars. Following their launch last year, pharmacy benefit managers largely influenced patient access, with minimal incentive for doctors to switch to these alternatives. Related: AbbVie Is ‘Successfully Positioned To Absorb Humira Biosimilar Erosion’: Analyst. Lower-priced biosimilars ...