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PURINETHOL

NDA

MERCAPTOPURINE | N009053 | STASON PHARMACEUTICALS INC

1 strength0 unique patents0 unique exclusivities

PTAB Proceedings

No IPR/PGR/CBM challenges found at the Patent Trial and Appeal Board

Patent Reexaminations

No ex parte or inter partes reexamination proceedings found at USPTO

Hatch-Waxman Litigation

No ANDA patent litigation cases (NOS 835) matched from PACER

Citizen Petitions

2 petitions from Regulations.gov

Petition	Type	Filed	Status	Petitioner
Citizen Petition from Zydus Pharmaceuticals Inc FDA-2014-P-1044 · 7 docket documents Zydus Pharmaceuticals (USA), Inc. filed this citizen petition on July 14, 2014, requesting that the FDA amend the Orange Book to designate a second reference listed drug for Mercaptopurine Tablets, specifically requesting that products from Mylan and/or Roxane be designated as alternative reference	505(q)	2014-09-11	Withdrawn	Zydus Pharmaceuticals Inc
Lachman Consultant Services, Inc. - Citizen Petition FDA-2010-P-0582 · 6 docket documents Lachman Consultant Services, Inc. filed this petition on behalf of a client under Section 505(j)(2)(C) of the Federal Food, Drug and Cosmetic Act requesting that the FDA declare Mercaptopurine Tablets, 25 mg suitable for an ANDA, with Purinethol Tablets 50 mg as the reference-listed drug. The petiti	Other	2010-12-27	Granted	—

Source: Regulations.gov. FDA citizen petitions matched by application number.

Clinical Trials

167 trials from ClinicalTrials.gov — 9 recruiting, 13 active, 105 completed

Trial	Phase	Status	Sponsor	Enrollment	Dates
Treatment of Newly Diagnosed Acute Lymphoblastic Leukemia in Children and Adolescents NCT03020030	Phase 3	Active	Dana-Farber Cancer Institute	560	2017-03-03 → 2034-11
Blinatumomab in Treating Younger Patients With Relapsed B-cell Acute Lymphoblastic Leukemia NCT02101853	Phase 3	Active	National Cancer Institute (NCI)	669	2014-12-17 → 2026-09-16
Response-Based Chemotherapy in Treating Newly Diagnosed Acute Myeloid Leukemia or Myelodysplastic Syndrome in Younger Patients With Down Syndrome NCT02521493	Phase 3	Active	Children's Oncology Group	280	2015-12-23 → 2026-06-30
A Study to Investigate Blinatumomab in Combination With Chemotherapy in Patients With Newly Diagnosed B-Lymphoblastic Leukemia NCT03914625	Phase 3	Active	National Cancer Institute (NCI)	6,720	2019-07-03 → 2027-09-30
LCH-IV, International Collaborative Treatment Protocol for Children and Adolescents With Langerhans Cell Histiocytosis NCT02205762	Phase 2/3	Active	North American Consortium for Histiocytosis	1,400	2016-11-02 → 2026-07
Blinatumomab and Combination Chemotherapy or Dasatinib, Prednisone, and Blinatumomab in Treating Older Patients With Acute Lymphoblastic Leukemia NCT02143414	Phase 2	Active	National Cancer Institute (NCI)	53	2015-06-30 → 2027-01-26
Total Therapy for Infants With Acute Lymphoblastic Leukemia (ALL) I NCT02553460	Phase 1/2	Active	St. Jude Children's Research Hospital	50	2016-01-29 → 2031-10
Imatinib Mesylate and Combination Chemotherapy in Treating Patients With Newly Diagnosed Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia NCT03007147	Phase 3	Active	Children's Oncology Group	475	2017-08-08 → 2027-09-30
Combination Chemotherapy With or Without Blinatumomab in Treating Patients With Newly Diagnosed BCR-ABL-Negative B Lineage Acute Lymphoblastic Leukemia NCT02003222	Phase 3	Active	National Cancer Institute (NCI)	488	2014-05-19 → 2027-02-25
ASIA Down Syndrome Acute Lymphoblastic Leukemia 2016 NCT03286634	Phase 2	Active	National Hospital Organization Nagoya Medical Center	60	2017-04-18 → 2033-03-31

Source: ClinicalTrials.gov. Trials matched by ingredient name.

Drug Pricing (NADAC)

National Average Drug Acquisition Cost — Week of 2026-07-15 | 1 NDC

Highest NADAC/Unit

$0.9204

per ea

Lowest NADAC/Unit

$0.9204

per ea

Brand NDCs

Generic NDCs

NDC Description	NADAC/Unit	Unit	Type	Generic NADAC	Effective
71921015002MERCAPTOPURINE 50 MG TABLET	$0.9204	EA	Generic	—	2026-06-17

Source: NADAC (data.medicaid.gov). Prices reflect national average acquisition costs for retail community pharmacies.

API Supply Chain2 active DMFs5 inactive

2 active API suppliers hold Drug Master Files for this ingredient. Limited supplier base — potential supply chain risk.

AARTI PHARMALABS LTDMERCAPTOPURINE

DMF 229712009

ZHEJIANG CHENG YI PHARMACEUTICAL CO LTDMERCAPTOPURINE

DMF 268492012

CHANGZHOU SIYAO PHARMACEUTICALS CO LTDInactiveMERCAPTOPURINE USP

DMF 165752003

ZHEJIANG CHENG YI PHARMACEUTICAL CO LTDInactiveMERCAPTOPURINE USP

DMF 168052003

ZHEJIANG CHENG YI PHARMACEUTICAL CO LTDInactiveMERCAPTOPURINE, USP, NON-STERILE ACTIVE PHARMACEUTICAL INGREDIENT

DMF 196682006

BENZOCHEM LIFESCIENCES PVT LTDInactiveMERCAPTOPURINE USP

DMF 212672008

RPG LIFE SCIENCES LTDInactiveMERCAPTOPURINE USP

DMF 217582008

Source: FDA Drug Master Files (fda.gov). Type II API DMFs matched by ingredient.

Approval Letters

8 letters from Drugs@FDA

Date	Submission	Document
Jul 10, 2024	SUPPL -44	View Letter (PDF)
Dec 30, 2020	SUPPL -40	View Letter (PDF)
Apr 30, 2020	SUPPL -39	View Letter (PDF)
May 24, 2018	SUPPL -35	View Letter (PDF)
May 31, 2011	SUPPL -32	View Letter (PDF)
Jan 10, 2003	SUPPL -22	View Letter (PDF)
Sep 6, 2002	SUPPL -21	View Letter (PDF)
Mar 22, 2002	SUPPL -20	View Letter (PDF)

Source: Drugs@FDA application documents.

Products (1)

#002 — 50MG **Federal Register determination that product was not discontinued or withdrawn for safety or effectiveness reasons**

RLDAB

0 patents0 exclusivities▴

TABLET;ORAL | Approved: Approved Prior to Jan 1, 1982

No patent or exclusivity listings for this strength.