Stuart Kassan, MD
Rheumatology · Denver, CONPI 1093706475
Payments from drug & device makers
What this record shows
Almost everything reported here is food and beverage — 99.3% of the total across 165 separate payments, which is the pattern of a clinician who attends manufacturer presentations rather than one with a consulting arrangement. It is spread thinly across 18 manufacturers, the largest accounting for just 22.8% — the pattern of someone who eats at a lot of different presentations. Reporting peaked in 2022 at $1,033 and has fallen 97.2% since, to $29 in 2023.
Across 165 payments — averaging $15.21 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- GSK$573
- AbbVie$448
- Amgen$336
- ANI Pharmaceuticals, Inc.$219
- Novartis$215
- Genentech USA, Inc.$196
- plus $522 from 12 others
Across 25 payments — averaging $2900.44 each. Payments tied to a research study. These frequently flow through the physician to a hospital or research institution rather than to the physician personally.
- AbbVie$34K
- Servier Bioinnovation$14K
- Novartis$12K
- Janssen Research & Development, LLC$7K
- E.r. Squibb & Sons, L.L.C.$6K
What the payments were for
- Food & beverage$2,49399%
- Education$161%
Most of this is food and beverage — typically meals provided during product presentations at a clinic or hospital. Nationally that is the single largest category of reported payments by count.
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| GSK | 38 | $573 |
| AbbVie | 30 | $448 |
| Amgen(2 entities) | 18 | $336 |
| ANI Pharmaceuticals, Inc. | 21 | $219 |
| Novartis | 19 | $215 |
| Genentech USA, Inc. | 11 | $196 |
| E.r. Squibb & Sons, L.L.C. | 8 | $114 |
| Mallinckrodt Hospital Products Inc. | 5 | $110 |
| Pfizer | 5 | $87 |
| Boehringer Ingelheim | 1 | $37 |
| Idorsia Pharmaceuticals US Inc | 2 | $28 |
| AstraZeneca | 1 | $24 |
| UCB, Inc. | 1 | $24 |
| Eisai Inc. | 1 | $23 |
| Sanofi-aventis U.S. LLC | 1 | $23 |
| Octapharma USA, Inc. | 1 | $20 |
| Johnson & Johnson | 1 | $17 |
| Merck | 1 | $16 |
How this compares
$2,510 in reported general payments places this provider in the 60th percentile of 108 rheumatology providers in Colorado.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| Orencia ClickjectAbatacept | 12 | $77,256 |
| BenlystaBelimumab | 12 | $59,948 |
| Hydroxychloroquine Sulfate | 317 | $14,014 |
| Cevimeline Hcl | 42 | $9,735 |
| Pilocarpine Hcl | 56 | $6,953 |
| Celecoxib | 28 | $3,421 |
| Prednisone | 186 | $2,372 |
| Mycophenolate Mofetil | 23 | $2,363 |
| Leflunomide | 23 | $1,658 |
| MethotrexateMethotrexate Sodium | 76 | $1,388 |
| Gabapentin | 43 | $1,292 |
| Dapsone | 14 | $1,249 |
| Minocycline Hcl | 24 | $1,237 |
| Duloxetine Hcl | 24 | $747 |
| Vitamin D2Ergocalciferol (Vitamin D2) | 40 | $694 |
Paid to pharmacies, not to this prescriber.
Companies that both paid and supply prescribed drugs
These companies both reported payments to this provider and make drugs the provider prescribed under Medicare Part D in 2024. For most specialties this overlap is expected — a cardiologist who is paid by a cardiology drugmaker also treats heart disease. It is shown so the reader can see it, not because it implies anything on its own.
| Company | Paid to this provider | Part D cost of their drugs |
|---|---|---|
| GSKBenlysta | $573 | $59,94812 claims |
| AbbVieSynthroid | $448 | $48612 claims |
Reading this fairly. The Part D column is what drug plans and patients paid pharmacies — this provider received none of it, and it reflects how many patients they treat and what those drugs cost. Against peers, this provider's reported payments sit in the 60th percentile of 108 rheumatology providers in Colorado.
Other rheumatology in Denver
- Aryeh FischerDenver$114K
- Adam BerlinbergDenver$94K
- Rennie McCabeDenver$58K
- Barbara GoldsteinDenver$47K
- Christopher AntoliniDenver$34K
- Mehrnaz Maleki FischbachDenver$25K
- Liudmila KastsianokDenver$22K
- David KormanDenver$20K
- Kathleen SrockDenver$19K
- Mary DemoruelleDenver$12K
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.