(CNN)For its investigation into H.P. Acthar Gel, CNN analyzed payment and prescription data from the Centers for Medicare & Medicaid Services.
Drug utilization and spending
To calculate how much the Medicare Part D program has spent on Acthar, CNN combined the 2011-2015 spending totals from the agency's Drug Spending and Utilization file for those years with the 2016 spending total from its 2012-2016 file.
The analysis found that from 2011 to 2016, Medicare has spent nearly $2 billion on 45,297 Acthar claims.
These figures capture the gross cost, which includes payments made by the government, the patient and any third parties. It also excludes any manufacturer or pharmacy rebates or discounts.
Read more about Medicare's Drug Spending data here.
To analyze doctors' prescribing patterns, CNN analyzed data from Medicare's 2016 Provider Utilization and Payment Data: Part D Prescriber Public Use File. The data provides claim and spending totals for each doctor who filed more than 10 claims for a given drug with the Medicare Part D program in 2016, the most recent year of data available.
CNN's analysis found that 352 doctors filed more than 10 Acthar claims that year, costing the program almost $369 million.
The Part D data has a number of limitations. For example, since this data only captures information from Part D patients, these figures may not be representative or fully inclusive of a doctor's entire prescribing pattern. They may also be an undercount, since prescribers can submit claims under an organization's ID number instead of their own.
Read more about Medicare's Part D data here.
CNN analyzed Medicare's Open Payments data to calculate how much Acthar's manufacturers, Mallinckrodt and Questcor, paid doctors between 2013 and 2016.
That data, which is released under a provision of the Affordable Care Act, collects information about payments — including, but not limited to, cash — that drug companies make to doctors and hospitals for research, ownership interests, travel, gifts, speaking fees, meals and other services.
CNN's analysis looked only at "general" payments, which excludes payments for research or doctors' ownership stakes in products or companies.
The analysis identified at least 18,810 physicians who received payments worth a cumulative total of nearly $27.5 million from 2013 to 2016.
For its reporting on which doctors received unusually large amounts of money, CNN used a statistical clustering tool to group doctors by the total value of their payments. The analysis created seven groups and CNN focused its reporting on the top two (i.e. the 16 doctors who received $220,405.72 or more from Mallinckrodt and Questcor).
Read more about Medicare's Open Payments data here.
Because Medicare's payments and prescriber files use different ID numbers to identify physicians, CNN used doctors' names, addresses and medical specialties from several years of payments and prescriber data to match the ID numbers. CNN then used these matches to identify which doctors received at least one payment from Mallinckrodt or Questcor between 2013 and 2016 and filed more than 10 Part D claims in 2016.
The analysis identified 352 doctors who filed more than 10 Part D claims for Acthar in 2016, 288 of whom had received at least one payment from the drug's manufacturer from 2013 to 2016.
For its reporting on which of those doctors received unusually large amounts of money, CNN used a statistical clustering tool to group doctors by the total value of their payments. The analysis created seven groups and CNN focused its reporting on the top two (i.e. the eight doctors who prescribed more than 10 claims in 2016 and received $224,713.96 or more between 2013 and 2016).
Drug sales and pricing
Drug prices vary widely for medications across the nation. For instance, some listings show the price of Acthar currently listed at more than $43,000 a vial.
For this story, CNN relied on the Wholesale Acquisition Cost -- the price set by manufacturers known in the industry as WAC -- for the pricing of Acthar as listed by First Databank, which describes itself as the "most widely used drug database proven across the entire healthcare spectrum."
According to First Databank, Acthar's price in 1990 was $21 per vial and is now listed around $39,000. Acthar's first dramatic price increase came after Questcor purchased the rights to Acthar in 2001, with the new price at $748. The price continued a steady climb in the 2000s until it skyrocketed overnight from around $1,650 to $23,200 on August 27, 2007.
According to First Databank, Acthar's price has continued on an upward climb ever since Mallinckrodt bought Questcor in 2014, with the price rising from $32,000 a vial to its current listing of about $39,000 in the four years since.
Read Mallinckrodt's response to this analysis here.