The rising price for EpiPens since the autoinjector device was acquired by Mylan in 2007 can’t come close to the increase in how much Medicare Part D spends on it, according to an analysis from the Kaiser Family Foundation.

The cost for a two-pack of EpiPens has risen nearly 550 percent according to Kaiser, from $94 in 2007 to $609 in 2016. Medicare Part D spending on the device went by by 1,151 percent between 2007 and 2014, going from $7 million annually to nearly $88 million.

There were more EpiPen users in Part D in that time frame, rising from just under 80,000 in 2007 to 211,000 in 2014, that 164 percent increase is far below the jump in spending in percentage terms.

The analysis also found total Part D spending per EpiPen prescription increased nearly 500 percent (from $71 in 2007 to $344 in 2014) and its annual growth in per-prescription spending outpaced both average Part D costs and inflation.

Kaiser did attempt to factor in rebates for the device, an argument Mylan has used against mounting criticism for the price increases. If it's assumed all Part D plans received the average annual rebate reported by Medicare actuaries (ranging from 9.6 percent in 2007 to 14.3 percent in 2014), the 1,100 percent increase in spending remained.

“In other words, even if total Part D spending for the EpiPen had been lower each year as a result of rebates, we might still expect to see a similar trend in the rate of Medicare Part D spending growth for the EpiPen, unless plans received significantly larger rebates over time,” Kaiser researchers Juliette Cubanski, Tricia Neuman and Anthony Damico wrote. “But it could also be the case that plans received relatively low rebates for the EpiPen, due to the lack of competition for this product—a situation that gives drug manufacturers less incentive to negotiate price discounts with insurers.”

The scrutiny of Mylan over the price increases doesn’t appear to be letting up. The attorney general of West Virginia, where the company is based, asked a judge on Sept. 20 to enforce a subpoena for information on EpiPen pricing, saying Mylan has failed to respond to the majority of the request for documents as the state investigates for potential Medicaid fraud.