An Pang Chieng, MD
Internal Medicine · Los Angeles, CANPI 1821030305
Payments from drug & device makers
Across 146 payments — averaging $22.78 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- Amarin Pharma, Inc.$569
- Merck$456
- AstraZeneca$289
- Amgen$247
- Otsuka America Pharmaceutical, Inc.$245
- Boehringer Ingelheim$224
- plus $1K from 16 others
What the payments were for
- Speaking & faculty fees$592%
- Food & beverage$3,19196%
- Education$772%
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 |
|---|---|---|
| Amarin Pharma, Inc. | 38 | $569 |
| Merck | 16 | $456 |
| AstraZeneca | 10 | $289 |
| Amgen | 10 | $247 |
| Otsuka America Pharmaceutical, Inc. | 9 | $245 |
| Boehringer Ingelheim | 9 | $224 |
| AbbVie | 5 | $202 |
| Lilly USA, LLC | 7 | $190 |
| Bayer | 3 | $163 |
| Novo Nordisk | 8 | $156 |
| Pfizer | 10 | $146 |
| Kyowa Kirin, Inc. | 4 | $92 |
| Sanofi Pasteur Inc. | 2 | $62 |
| GSK | 3 | $54 |
| Gilead | 3 | $48 |
| Salix Pharmaceuticals, A Division Of Bausch Health US, LLC | 3 | $48 |
| Exact Sciences | 1 | $31 |
| Novartis | 1 | $24 |
| Ironshore Pharmaceuticals Inc. | 1 | $24 |
| Kowa Pharmaceuticals America, Inc. | 1 | $23 |
| ITI, Inc. (d/b/a Intra-cellular Therapies, Inc.) | 1 | $21 |
| Aimmune Therapeutics, Inc. | 1 | $14 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
How this compares
$3,326 in reported general payments places this provider in the 85th percentile of 13,581 internal medicine providers in California.
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 |
|---|---|---|
| OzempicSemaglutide | 49 | $58,044 |
| FarxigaDapagliflozin Propanediol | 82 | $57,181 |
| ProliaDenosumab | 25 | $42,016 |
| TrulicityDulaglutide | 37 | $41,035 |
| JardianceEmpagliflozin | 42 | $37,555 |
| VascepaIcosapent Ethyl | 109 | $34,659 |
| JanumetSitagliptin Phos/Metformin Hcl | 22 | $28,680 |
| XareltoRivaroxaban | 28 | $22,701 |
| SynjardyEmpagliflozin/Metformin Hcl | 31 | $21,946 |
| VemlidyTenofovir Alafenamide | 13 | $17,471 |
| MyrbetriqMirabegron | 21 | $11,490 |
| Icosapent Ethyl | 63 | $10,647 |
| Janumet XrSitagliptin Phos/Metformin Hcl | 13 | $8,683 |
| Anoro ElliptaUmeclidinium Brm/Vilanterol Tr | 19 | $8,125 |
| Breo ElliptaFluticasone/Vilanterol | 16 | $5,884 |
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 |
|---|---|---|
| Boehringer IngelheimJardiance, Synjardy | $224 | $59,50173 claims |
| Novo NordiskOzempic | $156 | $58,04449 claims |
| AstraZenecaFarxiga | $289 | $57,18182 claims |
| AmgenProlia | $247 | $42,01625 claims |
| Lilly USA, LLCTrulicity | $190 | $41,03537 claims |
| MerckJanumet, Janumet Xr | $456 | $37,36335 claims |
| GileadVemlidy | $48 | $17,47113 claims |
| GSKAnoro Ellipta, Breo Ellipta | $54 | $14,00935 claims |
| Kowa Pharmaceuticals America, Inc.Livalo | $23 | $4,18713 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 85th percentile of 13,581 internal medicine providers in California.
Other internal medicine in Los Angeles
- William TownerLos Angeles$27.4M
- Herbert EradatLos Angeles$11.6M
- Deborah WongLos Angeles$10.7M
- Robin KelleyLos Angeles$5.8M
- David GuzmanLos Angeles$4.3M
- Siwen Hu-LieskovanLos Angeles$2.9M
- Andrew ChengSouth San Francisco$55.1M
- Joel NeutelTustin$34.9M
- Donald BrandonSan Diego$34M
- Rahul AggarwalSan Francisco$24M
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.