Trends and Characteristics of US Medicare Spending on Repository Corticotropin

Abstract

This study uses Medicare Drug Spending Dashboard data to estimate the cost of repository corticotropin to the Medicare program and assess its within-specialty prescribing patterns.

Repository corticotropin (rACTH) injection (H. P. Acthar gel; Mallinckrodt Pharmaceuticals) has been under intense scrutiny for its very high cost. Because rACTH is approved for a variety of immunologic conditions prevalent in the US Medicare population, prescriptions for rACTH may have a significant financial impact on Medicare expenditures. The objectives of this study were to (1) estimate the cost of rACTH to the Medicare program, and (2) assess the within-specialty prescribing patterns for this medication.

Methods

We summarized aggregate rACTH spending, prescriptions, and beneficiaries from 2011 to 2015 using Medicare Drug Spending Dashboard data. We used Medicare Part D Public Use Files (PUFs) to determine rACTH utilization by physician specialty. For frequent prescribers (those with more than 10 rACTH claims; drugs with 10 or fewer claims are suppressed for privacy), we summarized expenditures, prescription counts, and unique beneficiaries by physician specialties we anticipated to be the largest prescribers of rACTH: rheumatology, neurology, and nephrology. We also estimated rACTH utilization for those with 10 or fewer rACTH claims (infrequent prescribers) by extrapolating the residual aggregate rACTH utilization (total minus frequent prescriber utilization) across all other Part D prescribing rheumatologists, neurologists, and nephrologists. We used the Provider Summary PUF to estimate non-rACTH drug utilization by subtracting rACTH utilization from their total drug utilization for both frequent and infrequent prescribers. Analyses were conducted using SAS statistical software (version 9.4; SAS Institute) and Excel (Microsoft). The research used publicly available data sources and was exempt from institutional review board approval.

Results

Medicare spending on rACTH increased 10-fold and totaled $1.3 billion from 2011 to 2015 (Table 1). This spending increase was driven by a 109% increase prescriptions per beneficiary, a 264% increase in the number of beneficiaries prescribed rACTH, and a 180% increase in spending per beneficiary.

Table 1. Aggregate Utilization of Repository Corticotropin Injection in US Medicare Program 2011 to 2015.

Year	Total Spending, $	Claims, No.	Cost per Claim, $	Beneficiaries, No.	Claims per Beneficiary, No.	Cost per Beneficiary, $
2011	49 456 911	1471	33 621	853	1.72	57 980
2012	141 451 608	3387	41 763	1583	2.14	89 357
2013	262 581 602	6752	38 889	2431	2.78	108 014
2014	391 189 653	9611	40 702	2932	3.28	133 421
2015	503 999 371	11 209	44 964	3104	3.61	162 371
Percentage change, 2011 to 2015	919	662	34	264	109	180

In 2014, 1621 of 1 072 997 Part D prescribers (0.2%) were responsible for $391.2 million in rACTH spending. As shown in Table 2, rheumatologists (n = 94), neurologists (n = 55), and nephrologists (n = 54) represented 84% of all frequent prescribers of rACTH (n = 243), and accounted for 42% ($165.0 million) of all rACTH spending. These frequent prescribers represented only 0.4% to 2.1% of all prescribers within their respective specialties. Despite comprising fewer than 0.5% of their total prescriptions, rACTH accounted for more than one-third of total Part D expenditures for these frequent specialist prescribers.

Table 2. Medicare Part D Utilization for Frequent Repository Corticotropin Injection Prescribers Relative to Their Specialty Peers (2014)^a.

	Rheumatology		Neurology		Nephrology		Specialty Totalb		All FPs, (n = 243)c
	FPs (n = 94)	IPs (n = 4323)	FPs (n = 55)	IPs (n = 13 178)	FPs (n = 54)	IPs (n = 8030)	FPs (n = 203)	IPs (n = 25 531)
Spending, $
rACTH spending	90 893 473	88 987 094	41 915 298	41 036 176	32 179 323	31 504 401	164 988 094	161 527 671	197 667 746
rACTH pending per prescriber	966 952	20 585	762 096	3 114	595 913	3 923	812 749	6327	813 448
Other drug spending	115 389 913	2 496 839 483	163 485 548	5 805 530 003	26 563 026	2 135 182 185	305 438 486	10 437 551 671	349 329 447
Other drug spending per prescriber	1 227 552	577 571	2 972 465	440 547	491 908	265 901	1 504 623	408 819	1 437 195
Prescriptions, No.
rACTH prescriptions	2279	2065	1052	953	878	796	4209	3814	5042
rACTH prescriptions per prescriber	24	0.5	19	0.1	16	0.1	21	0.2	21
Other drug prescriptions	432 314	11 431 881	284 208	20 601 963	178 338	15 995 227	894 860	48 029 071	1 087 613
Other drug prescriptions per prescriber	4599	2644	5167	1563	3303	1992	4408	1881	4476
Beneficiaries, No.d
rACTH beneficiaries	532	547	392	403	270	277	1194	1227	1446
rACTH beneficiaries per prescriber	5.7	0.1	7.1	0.03	5.0	0.03	5.9	0.05	6.0
rACTH prescriptions per beneficiary	4.3	3.8	2.7	2.4	3.3	2.9	3.5	3.1	3.5
Other drug beneficiaries	41 242	1 236 676	21 726	2 394 249	14 329	1 524 306	77 297	5 155 231	91 444
Other drug beneficiaries per prescriber	439	286	395	182	265	190	381	202	376
Other drug prescriptions per beneficiary	10.5	9.2	13.1	8.6	12.4	10.5	11.6	9.3	11.9

Abbreviations: FP, frequent repository corticotropin prescriber; IP, infrequent repository corticotropin prescriber; rACTH, repository corticotropin.

^aMedicare Part D prescribers with more than 10 rACTH prescriptions.

^bRheumatology, neurology, nephrology specialty total.

^cIncludes 40 prescribers from other specialties.

^dFive beneficiaries imputed for suppressed values and assumes each beneficiary receives prescriptions from 1 prescriber.

rACTH spending per prescriber was 128 times higher for frequent prescribers than their specialty peers ($812 749 vs $6327). While the number of rACTH prescriptions per beneficiary were similar between frequent and infrequent prescribers (3.5 vs 3.1 per beneficiary), frequent prescribers had substantially more beneficiaries receiving rACTH prescriptions (5.9 vs 0.05 per prescriber). Other prescriptions per beneficiary were only 25% higher (11.6 vs 9.3 other drug prescriptions per beneficiary) among frequent vs infrequent prescribers.

Discussion

Medicare expenditures for rACTH have risen dramatically in recent years. In 2015, Medicare spent over half a billion dollars on rACTH, making it the 52nd most costly medication for the program. We attribute much of this growth to increased prescribing intensity across a very small number of rheumatologists, neurologists, and nephrologists, who wrote 100 times more rACTH prescriptions than their colleagues. Other prescriptions written per beneficiary were only modestly increased among frequent prescribers, suggesting that differences in intensity of rACTH use is not entirely explained by frequent prescribers treating more severely ill beneficiaries. Three of us (A.D., D.M.C., and D.N.B.) have met with representatives of Questcor or Mallinckrodt Pharmaceuticals and have experienced high-pressure sales tactics. It s unknown how broadly used and how much influence accrue to such tactics. rACTH use may be driven by financial conflicts of interest.

A lack of confidential rebate data prevents estimating Medicare’s net expenditures. Transcripts from a recent earnings report call suggest rebates are likely around 10%.

For adult indications, there is little evidence that rACTH is superior to cheaper synthetic corticosteroids. Despite this, Mallinckrodt Pharmaceuticals reported $1.03 billion in worldwide sales from rACTH in 2015, roughly half of which is likely derived from the Medicare program. Physicians should be aware of this lack of evidence when prescribing this highly expensive drug.