Specialty drugs accounted for 37.7% of retail and mail-order prescription spending, net of rebates, in 2016 and 2017, according to a recent study published in Health Affairs. Average annual net spending on retail specialty drugs for Medicare Part D beneficiaries rose from $11.3 billion in 2010-2011 to $35.4 billion in 2016-2017. For private insurance enrollees, net spending increased from $24.6 billion to $57.6 billion during that time period. The growth in spending was partially driven by the increased use of retail specialty drugs — the proportion of people who obtained at least one specialty drug was 5.0% in 2016-2017, more than doubling the rate observed in 2010-2011. Meanwhile, the trend in Medicaid net spending was relatively flat.