Weiyun Ai, MD
Medical Oncology · San Francisco, CANPI 1649346842
Payments from drug & device makers
What this record shows
This record is dominated by consulting fees: $29,516 of the $36,649 with a category attached, or 80.5%. 14 manufacturers reported payments, led by Kyowa Kirin, Inc. at 37.8% of the total. Reporting peaked in 2019 at $13,821 and has fallen 63.5% since, to $5,038 in 2025.
Across 59 payments — averaging $621.17 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- Kyowa Kirin, Inc.$14K
- Acrotech Biopharma Inc.$6K
- Gilead$4K
- AbbVie$4K
- Seagen Inc.$3K
- Beigene USA, Inc.$2K
- plus $4K from 8 others
Across 101 payments — averaging $8452.87 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.
- Daiichi Sankyo Inc.$415K
- Eli Lilly$127K
- Pfizer$91K
- Seagen Inc.$81K
- Bristol Myers Squibb$49K
- ADC Therapeutics America, Inc.$41K
- plus $50K from 2 others
What the payments were for
- Consulting fees$29,51681%
- Speaking & faculty fees$2,5007%
- Travel & lodging$2,3206%
- Food & beverage$2,2526%
- Education$610%
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 |
|---|---|---|
| Kyowa Kirin, Inc. | 17 | $13,851 |
| Acrotech Biopharma Inc. | 9 | $5,805 |
| Gilead(2 entities) | 3 | $4,350 |
| AbbVie | 9 | $3,850 |
| Seagen Inc. | 5 | $2,886 |
| Beigene USA, Inc. | 1 | $1,950 |
| Aurobindo Pharma USA, Inc. | 4 | $1,665 |
| Secura Bio, Inc. | 1 | $1,500 |
| AstraZeneca | 3 | $387 |
| ADC Therapeutics America, Inc. | 2 | $213 |
| Pfizer | 1 | $82 |
| Pharmacyclics LLC, An Abbvie Company | 2 | $44 |
| EMD Serono, Inc. | 1 | $41 |
| Genmab U.S., Inc. | 1 | $25 |
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
$36,649 in reported general payments places this provider in the 75th percentile of 379 medical oncology 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 |
|---|---|---|
| BrukinsaZanubrutinib | 36 | $492,169 |
| VenclextaVenetoclax | 33 | $450,666 |
| CalquenceAcalabrutinib Maleate | 16 | $236,062 |
| Bexarotene | 14 | $61,344 |
| Entecavir | 22 | $2,521 |
| Acyclovir | 85 | $1,426 |
| ValacyclovirValacyclovir Hcl | 38 | $1,260 |
| Clobetasol Propionate | 24 | $1,004 |
| Ondansetron Hcl | 34 | $675 |
| Triamcinolone Acetonide | 28 | $550 |
| Gabapentin | 29 | $279 |
| Levothyroxine Sodium | 17 | $218 |
| Sulfamethoxazole-TrimethoprimSulfamethoxazole/Trimethoprim | 29 | $124 |
| MethotrexateMethotrexate Sodium | 12 | $116 |
| Allopurinol | 15 | $107 |
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 |
|---|---|---|
| Beigene USA, Inc.Brukinsa | $1,950 | $492,16936 claims |
| AbbVieVenclexta | $3,850 | $450,66633 claims |
| AstraZenecaCalquence | $387 | $236,06216 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 75th percentile of 379 medical oncology providers in California.
Other medical oncology in San Francisco
- Stephen SherwinSan Francisco$6.9M
- John ParkSan Francisco$558K
- Kevin KimSan Francisco$176K
- Aman ChauhanSan Francisco$99K
- Ana Velazquez MananaSan Francisco$90K
- Noam DrazinBeverly Hills$1.4M
- Farshid DayyaniOrange$1.2M
- April TeitelbaumSan Diego$1.1M
- Przemyslaw TwardowskiSanta Monica$995K
- Ann LowePalo Alto$923K
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.