Provisions in President Joe Biden's proposed $1.75 trillion social spending package would put a damper on drug manufacturers' ability to control prices, but big pharma lobbyists are putting up a fierce fight. Meanwhile, a U.S. agency has reported that unjustified increases in prescription drug prices in 2020 resulted in $1.67 billion in additional spending by consumers.

According to the Institute for Clinical and Economic Review (ICER), a Boston-based medicine value monitoring agency, ten of the most expensive prescription drugs in the country saw unjustified price hikes.

Of those price increases, AbbVie Inc.'s (ABBV  ) 10% boost on the price of popular rheumatoid arthritis drug Humira accounted for the vast majority of the increased spending, costing U.S. patients an additional $1.4 billion in 2020 alone.

Novartis (NVS  ) instituted that largest price increase, raising the price of Promacta, a drug used to treat aplastic anemia, by more than 14%, or $100 million in total spending.

The institute reportedly studied data and input gathered by the drug manufacturers themselves and was unable to find any new benefits of the drugs which would justify their increased prices.

Rind said that unjustified drug price hikes have decreased since ICER began making reports on the issue, but that the most expensive drugs continue to see price escalations.

"Several of these treatments have been on the market for many years, with scant evidence that they are any more effective than we understood them to be years ago when they cost far less," ICER Chief Medical Officer David Rind said in a statement.

"The most extreme of these is Humira," Rind continued, "with an ever-escalating U.S. price that contrasts starkly to its falling price in every country where Humira currently faces biosimilar competition."

In 2019, Americans spent around $350 billion on prescription drugs, more than twice as much per person than spending in other developed countries.

In its defense, AbbVie said that ICER had not conducted a sufficient assessment, in part because it allegedly failed to take into account data reported from smaller patient populations. Novartis also said that ICER had failed to take into account new health and economic data which allegedly justified the company's price hike. Both specifically stated that ICER's judgments weren't accurate because the agency doesn't perform full value assessments.