US drug spending grew by a double digit percentage, for the second year in a row, shows a report by IMS Institute for Healthcare Informatics. Payers spent US$425 billion in 2015, an increase of more than 12% from 2014. The rate of growth was reduced slightly compared with 2014.

The increased drug expenditure was due primarily to the launch of new drugs, IMS reports, but there was also a small rise in the volume of branded drug usage. Although the average price of branded drugs also increased, the change in average price was lower than in previous years. The average price of branded drugs grew by 2.8% in 2015, compared with a 5.1% increase in 2014, a 4.1% increase in 2013 and a 9.1% increase in 2012. “This reflects the heightened competition among manufacturers and more aggressive efforts by health plans and pharmacy benefit managers to limit price growth,” the report says.

Oncology, the largest specialty medicine spending segment, brought in $39.1 billion. This was an increase of 18% compared with 2014. The fastest growing class of oncologics is still protein kinase inhibitors, which saw growth of 27%. Immuno-oncology monoclonal antibodies against programmed cell death protein 1 (PD1) also saw rapid uptake.

Hepatitis drugs and autoimmune treatments also drove spending higher, with spending on these medicines increasing by 54% and 29%, respectively.

US drug spending will hit $610–640 billion in 2020, IMS forecasts. Nearly one-third of this growth is expected to come from new medicines that will be launched in the coming years.