Philip Louis Marjon, M.D.
Hematology & Oncology Physician · San Marcos, CA
Philip Louis Marjon, M.D. is a hematology & oncology physician with a practice address in San Marcos, California, and NPI 1912234121, issued on Nov 9, 2009. Check the license (California C175032, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Philip Louis Marjon
- Credential
- M.D.
- Primary taxonomy
- Hematology & Oncology Physician 207RH0003X
- License number
- C175032 CA
Self-reported in NPPES; status is on the state search - Practice location
- 838 Nordahl RD Ste 300, San Marcos, CA 92069
- Phone
- (760) 747-8935
- Enumerated
- Nov 9, 2009
- Record last updated
- Dec 22, 2025
- Fax
- (760) 466-0078
- Medicare enrollment
- Enrolled (PECOS I20211029001903); accepts Medicare assignment
- Medical or professional school
- University Of New Mexico School Of Medicine, 2007
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest hematology & oncology physician records → All 1,583 in California → Look up another NPI →
Also registered at 838 Nordahl RD Ste 300
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Christine Adamo, DAOM, LACAcupuncturist1063748382
- Alanna Iorio, AGNPNurse Practitioner1295556256
- Jennifer Levine, PHYSICIAN ASSISTANT-Physician Assistant1316109614
- Edward McClay, M.D.Medical Oncology Physician1497727465
- Patricia Mooney, NURSE PRACTITIONERNurse Practitioner1700470200
- Farzaneh Salehi, NPFamily Medicine Physician1972311181
Verify Philip Louis Marjon in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license C175032Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
39% fewer Medicare Part D claims than the average hematology & oncology physician in 2024
531 Medicare Part D claims for 200 beneficiaries, against an average of 877 among the 10,784 providers of this specialty who prescribed in Part D. Brand-name drugs were 25% of claims. 22 claims were for opioids.
Most prescribed
- Letrozole111 claims
- Hydroxyurea46 claims
- Brukinsa17 claims
- Ondansetron Odt17 claims
- Prednisone17 claims
- Promacta17 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Industry payments in 2024: $6,240.10
227 payments; by number, the most common kind was food and beverage; the largest payer was E.R. Squibb & Sons, L.L.C. The 8,560 providers of this specialty with any payment received $7,481.41 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- California Cancer Associates For Research And Excellence IncSan Marcos, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Philip Louis Marjon among 1,583 hematology & oncology physician records in California
Philip Louis Marjon, M.D. is one of 1,583 hematology & oncology physician records with a practice address in California. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2009, is newer than 66% of them.
- NPI issued2009 · 66% of these records are older, 30% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 71% of these records are
- Graduated2007 · median 2003 among the 1,124 with a school on file
- Record last updated2025 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RH0003X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Hematology & Oncology Physician providers in California
There are 1,583 hematology & oncology physician records in California.
All 1,583 in California → Every provider in San Marcos → Hematology & Oncology Physician nationwide →
The 8 hematology & oncology physician records with the nearest ZIP codes
- Christine White, M.D.Rancho Santa Fe, CA 920671265535728
- Sujatha Murali, MDSan Marcos, CA 920781366478661
- Mark AdlerVista, CA 920811174552533
- Derek Helton, M.D.Vista, CA 920811801992839
- Rupa Subramanian, M.D.Vista, CA 920811376547174
- David Oblon, MDOceanside, CA 920561215072434
- Warren Paroly, MDOceanside, CA 920561306981527
- Catherine Quinn, M.D.Oceanside, CA 920561427403641
Common questions
What is Philip Louis Marjon, M.D.'s NPI number?
Philip Louis Marjon, M.D.'s National Provider Identifier (NPI) is 1912234121, issued on Nov 9, 2009. An NPI identifies a provider in billing; it is not a license.
Where is Philip Louis Marjon, M.D. located?
The NPPES record lists a practice address at 838 Nordahl RD Ste 300, San Marcos, CA, 92069. Phone: (760) 747-8935. Providers update this record themselves, so call before visiting.
How can I verify Philip Louis Marjon, M.D.'s license?
NPPES lists California license number C175032, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Philip Louis Marjon, M.D. prescribe under Medicare Part D?
In 2024, Philip Louis Marjon, M.D. had 531 Medicare Part D claims for 200 beneficiaries; the average among hematology & oncology physician prescribers was 877. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.