Healthcare provider profile · identity verified

Michael David Weiss

Allopathic & Osteopathic Physicians|Psychiatry & Neurology|Neurology · SEATTLE, WA · NPI 1639269582

Profile state: payments and partd Open Payments: 2025 Medicare Part D: 2024 Last identity check: 2026-08-10 Page data build: 2026-08-12

Verified facts

What the public records show

CMS Open Payments records show Michael David Weiss received $32,101.57 in general payments during 2025 across 54 reported records.

UCB, Inc. accounted for 38.1% of that reported general-payment amount.

The Open Payments records used for this analysis explicitly named 10 associated products.

A separate comparison found the same explicitly named product in public Medicare Part D data: Gamunex-C, Hizentra, Vyvgart Hytrulo.

ARGENX US, INC. reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported VYVGART HYTRULO as an associated drug or biological on 16156 records involving 4992 distinct recipient NPIs. Public Medicare Part D data also shows 12 claims for Vyvgart Hytrulo by this doctor in 2024.

CSL Behring reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported Hizentra as an associated drug or biological on 13634 records involving 4691 distinct recipient NPIs. Public Medicare Part D data also shows 26 claims for Hizentra by this doctor in 2024.

CSL Behring reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported Privigen as an associated drug or biological on 464 records involving 289 distinct recipient NPIs. Public Medicare Part D data also shows 26 claims for Privigen by this doctor in 2024.

Grifols Shared Services North America, Inc. reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported Gamunex-C as an associated drug or biological on 134 records involving 32 distinct recipient NPIs. Public Medicare Part D data also shows 27 claims for Gamunex-C by this doctor in 2024.

Takeda Pharmaceuticals U.S.A., Inc. reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported GAMMAGARD LIQUID as an associated drug or biological on 29 records involving 8 distinct recipient NPIs. Public Medicare Part D data also shows 79 claims for Gammagard Liquid by this doctor in 2024.

These records do not establish that a payment influenced prescribing or medical care.

Payment overview · 2025

General Payments

$32,101.57

54 reported records · 10 companies

Separate record types

Research & Ownership

Research Payments (direct recipient): not present in the loaded data

Associated Research Funding (for example, named PI): not present in the loaded data

Ownership / Investment: not present in the loaded data

These categories are never added into the General Payments headline. Associated research funding must not be described as money the doctor personally received unless the source record supports that conclusion.

Who paid this doctor?

Companies in 2025 General Payments

Reported companyCanonical companyAmountShareRecordsYear
UCB, Inc. Unresolved — no canonical attribution shown $12,235.1038.1%122025
Amgen Inc. Unresolved — no canonical attribution shown $7,818.2724.4%112025
ARGENX US, INC. Unresolved — no canonical attribution shown $7,277.7422.7%62025
Takeda Pharmaceuticals U.S.A., Inc. Unresolved — no canonical attribution shown $2,296.907.2%162025
GENZYME CORPORATION Unresolved — no canonical attribution shown $1,830.005.7%12025
Janssen Scientific Affairs, LLC Unresolved — no canonical attribution shown $196.590.6%22025
Grifols Shared Services North America, Inc. Unresolved — no canonical attribution shown $142.830.4%22025
CSL Behring Unresolved — no canonical attribution shown $141.040.4%12025
Biogen, Inc. Unresolved — no canonical attribution shown $134.240.4%22025
Alexion Pharmaceuticals, Inc. Unresolved — no canonical attribution shown $28.860.1%12025

What were the payments for?

Payment categories

CategoryAmountRecords
Compensation for services other than consulting, including serving as faculty or as a speaker at a venue other than a continuing education program$15,450.006
Consulting Fee$9,068.005
Travel and Lodging$5,514.3014
Food and Beverage$2,069.2729

A meal, consulting fee, royalty, and travel payment describe different kinds of reported relationships and should not be interpreted as equivalent.

Analysis 1 · Payment-linked products

Products named in Open Payments records

Reported productTypeReported companyRelated amount*RecordsYear
Rystiggo
Normalized: rystiggo
Drug UCB, Inc. $7,968.70 6 2025
Source payment records
VYVGART
Normalized: vyvgart
Drug ARGENX US, INC. $5,050.00 3 2025
Source payment records
Zilbrysq
Normalized: zilbrysq
Drug UCB, Inc. $4,072.83 4 2025
Source payment records
VYVGART HYTRULO
Normalized: vyvgart hytrulo
Drug ARGENX US, INC. $1,289.74 3 2025
Source payment records
UPLIZNA
Normalized: uplizna
Biological Amgen Inc. $550.00 1 2025
Source payment records
Hizentra
Normalized: hizentra
Biological CSL Behring $141.04 1 2025
Source payment records
QALSODY
Normalized: qalsody
Drug Biogen, Inc. $134.24 2 2025
Source payment records
HYQVIA
Normalized: hyqvia
Biological Takeda Pharmaceuticals U.S.A., Inc. $86.17 1 2025
Source payment records
ULTOMIRIS
Normalized: ultomiris
Biological Alexion Pharmaceuticals, Inc. $28.86 1 2025
Source payment records
Gamunex-C
Normalized: gamunex c
Biological Grifols Shared Services North America, Inc. $17.83 1 2025
Source payment records

* Product-associated amounts are non-additive because one payment record may name more than one product.

These products were named on specific Open Payments records. A named product does not show that the payment influenced treatment or prescribing.

Public prescribing for products named in payments

Open Payments productPayment yearPart D brandPart D yearClaimsMatch methodSource
Gamunex-C
gamunex c
2025 Gamunex-C 2024 27
Beneficiary count suppressed
exact normalized Medicare Part D
Hizentra
hizentra
2025 Hizentra 2024 26
Beneficiary count suppressed
exact normalized Medicare Part D
VYVGART HYTRULO
vyvgart hytrulo
2025 Vyvgart Hytrulo 2024 12
Beneficiary count suppressed
exact normalized Medicare Part D

The presence of the same drug in both datasets does not show that a payment caused or influenced a prescription.

Analysis 2 · Same-company prescribing overlap

Drugs reported in other payments from the same company that also appear in Medicare Part D

This analysis is independent from products named on this doctor’s individual payment records. A row appears only when the exact Open Payments reporting entity paid this doctor, that same reporting entity reported the drug or biological on at least 10 loaded General Payment records involving at least 2 distinct recipient NPIs, and this doctor has the same non-generic brand in public Part D data. This does not mean the company owns or manufactures the drug.

Paying companyPayment yearDrug reported by same entityOpen Payments evidencePart DClaimsBeneficiaries
ARGENX US, INC.
Exact reporting entity; no affiliate inference
2025 VYVGART HYTRULO
open payments reported associated product
CMS Open Payments — General Payments
16156 supporting records · 4992 recipient NPIs · example record 1240416058
Vyvgart Hytrulo · 2024
Exact normalized brand match · 1 Part D row
12 suppressed by CMS
CSL Behring
Exact reporting entity; no affiliate inference
2025 Hizentra
open payments reported associated product
CMS Open Payments — General Payments
13634 supporting records · 4691 recipient NPIs · example record 1232339012
Hizentra · 2024
Exact normalized brand match · 1 Part D row
26 suppressed by CMS
CSL Behring
Exact reporting entity; no affiliate inference
2025 Privigen
open payments reported associated product
CMS Open Payments — General Payments
464 supporting records · 289 recipient NPIs · example record 1232339064
Privigen · 2024
Exact normalized brand match · 1 Part D row
26 suppressed by CMS
Grifols Shared Services North America, Inc.
Exact reporting entity; no affiliate inference
2025 Gamunex-C
open payments reported associated product
CMS Open Payments — General Payments
134 supporting records · 32 recipient NPIs · example record 1249529874
Gamunex-C · 2024
Exact normalized brand match · 1 Part D row
27 suppressed by CMS
Takeda Pharmaceuticals U.S.A., Inc.
Exact reporting entity; no affiliate inference
2025 GAMMAGARD LIQUID
open payments reported associated product
CMS Open Payments — General Payments
29 supporting records · 8 recipient NPIs · example record 1223786557
Gammagard Liquid · 2024
Exact normalized brand match · 1 Part D row
79 suppressed by CMS

These facts do not show that a payment was for the drug, that the company owns or manufactures the drug, or that a payment caused or influenced prescribing.

Public Medicare Part D data

Provider-and-drug rows loaded for 2024

BrandGenericClaimsBeneficiaries
GabapentinGabapentin12824
PregabalinPregabalin10116
Gammagard LiquidImmun Glob G(Igg)/Gly/Iga Ov5079suppressed
PrednisonePrednisone7916
Radicava OrsEdaravone71suppressed
Mycophenolate MofetilMycophenolate Mofetil6212
Duloxetine HclDuloxetine Hcl5814
NuedextaDextromethorphan Hbr/Quinidine55suppressed
Pyridostigmine BromidePyridostigmine Bromide4913
RiluzoleRiluzole4812
BaclofenBaclofen44suppressed
Tramadol HclTramadol Hcl40suppressed
PrimidonePrimidone28suppressed
Gamunex-CImmune Globul G/Gly/Iga Avg 4627suppressed
HizentraImmun Glob G(Igg)/Pro/Iga 0-5026suppressed
PrivigenImmun Glob G(Igg)/Pro/Iga 0-5026suppressed
Amitriptyline HclAmitriptyline Hcl25suppressed
Oxybutynin ChlorideOxybutynin Chloride20suppressed
LevocarnitineLevocarnitine17suppressed
AzathioprineAzathioprine16suppressed
RelyvrioSod Phenylbutyrat/Taurursodiol16suppressed
MethocarbamolMethocarbamol13suppressed
DiazepamDiazepam12suppressed
Vyvgart HytruloEfgartigimod-Hyaluronidas-Qvfc12suppressed
GammaplexImmun Glob G(Igg)/Gly/Iga 0-5011suppressed
LorazepamLorazepam11suppressed
MethotrexateMethotrexate Sodium11suppressed

Timeline

Payment and prescribing data by year

Open Payments and Medicare Part D may refer to different years. They are shown separately rather than aligned as if they describe the same period.

YearGeneral PaymentsMain payerExplicit productsCompany overlapsPart D coverage
2025 $32,101.57 · 54 records UCB, Inc. Gamunex-C, HYQVIA, Hizentra, QALSODY, Rystiggo, ULTOMIRIS, UPLIZNA, VYVGART, VYVGART HYTRULO, Zilbrysq 5
2024 Complete

Questions to ask

Questions you could discuss with your doctor

These are general questions generated from reviewed templates. They are not personalized medical advice.

Sources and limitations

How to read this page

Loaded source releases

DatasetYearPublicationSource
CMS Open Payments — General Payments 2025 2026-06-30 Original source
Medicare Part D Prescribers by Provider and Drug 2024 2026-05-06 Original source
NPPES Data Dissemination V2 current / reference data 2026-08-10 Original source

Methodology version: 2.1

Editorial template version: 2.4

Product contract version: 2.0

Schema version: 0.7.0

Page data build: 2026-08-12T23:34:59.370714+00:00

Publication policy: eligible for indexing after public-launch controls are enabled

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