ModifiedmhnPolicy CP.PHAR.447

Clinical Policy: Mercaptopurine (Purixan)

Defines medical necessity criteria, prior authorization and continuation requirements for Purixan (mercaptopurine oral suspension) for treatment of acute lymphoblastic leukemia (ALL) and certain off-label leukemia uses for members under Centene-affiliated health plans.

Policy Summary

Payermhn

PolicyClinical Policy: Mercaptopurine (Purixan)

Policy CodePolicy CP.PHAR.447

Change TypeStep therapy and redirection updatesappendix and wording revisions

Effective Date03.01.20

Next Review Date

Key ActionPrior authorization is required and providers must submit documentation showing the member meets all approval criteria, including diagnosis, prescriber specialty, step therapy requirements, and dosing within limits.

SourceLink

POLICY UPDATE CHANGES

Added redirection to generic oral suspension; for redirection to mercaptopurine tablets revised verbiage from 'member must use' to 'failure of.'

Added step therapy bypass for IL HIM per IL HB 5395.

Modified commercial approval duration to '12 months or duration of request, whichever is less' and changed redirection language to 'member must use' (previous revision subsequently modified in 2025).

Revised verbiage for redirection to mercaptopurine tablets from 'member must use' to 'failure of.'

Updated Appendix E to include Mississippi.

2Q 2025 annual review: no significant changes; references reviewed and updated.

2.5 mg/kgMaximum ALL daily dose

1.5–2.5 mg/kgTypical ALL dosing

20 mg/mLOral suspension

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6 monthsMedicaid/HIM initial approval

12 monthsCommercial initial approval

IL HB 5395Legislation

Coverage and Medical Necessity Criteria

Initial Therapy — Covered when ALL of the following are met

Covered when ALL of the following are met

A. Acute Lymphoblastic Leukemia or Acute Myeloid Leukemia (must meet all): 1. Diagnosis of acute lymphoblastic leukemia (ALL) or acute promyelocytic leukemia (off-label); 2. Prescribed by or in consultation with an oncologist or hematologist; 3. Failure of mercaptopurine tablets, unless one of the following applies: (a) mercaptopurine tablets are contraindicated or clinically significant adverse effects are experienced; (b) documented swallowing disorder or inability to swallow tablets or capsules; (c) request is for treatment associated with cancer in a State with regulations against step therapy in certain oncology settings (see Appendix E). For Illinois HIM requests, step therapy requirements do not apply as of 1/1/2026 per IL HB 5395; 4. Member must use generic mercaptopurine oral suspension unless contraindicated, clinically significant adverse effects occur, or request is for treatment associated with cancer in a State with regulations against step therapy in certain oncology settings (see Appendix E); 5. Request meets ONE of the following: (a) dose does not exceed 2.5 mg/kg or 75 mg/m2 per day; OR (b) dose is supported by practice guidelines or peer-reviewed literature for the relevant off-label use (prescriber must submit supporting evidence).dose <= 2.5 mg/kg or 75 mg/m2/day

Approval duration: Medicaid/HIM 6 months; Commercial 12 months or duration of request, whichever is less

Continuation Therapy — Covered for continued therapy when ALL of the following are met

Covered for continued therapy when ALL of the following are met

II.A Continued Therapy for ALL/AML: 1. Member is currently receiving medication via the Centene benefit, or documentation supports that the member has been receiving mercaptopurine oral suspension (Purixan) for a covered indication for at least 30 days; 2. Member is responding positively to therapy; 3. Member must use generic mercaptopurine oral suspension unless contraindicated, clinically significant adverse effects occur, or request is for treatment associated with cancer in a State with regulations against step therapy in certain oncology settings (see Appendix E); 4. If the request is for a dose increase, the request meets ONE of the following: (a) the new dose does not exceed 5 mg/kg or 75 mg/m2 per day; OR (b) the new dose is supported by practice guidelines or peer-reviewed literature for the relevant off-label use (prescriber must submit supporting evidence).if dose increase: <= 5 mg/kg or 75 mg/m2/day

Approval duration: Medicaid/HIM 12 months; Commercial 12 months or duration of request, whichever is less

Non‑FDA approved indications that are not specifically addressed in this policy are not authorized unless the provider submits sufficient documentation demonstrating efficacy and safety in accordance with the applicable off‑label use policy (see CP.CPA.09 for Commercial, HIM.PA.154 for Health Insurance Marketplace, and CP.PMN.53 for Medicaid).

When state Medicaid coverage provisions conflict with the coverage language in this clinical policy for Medicaid members, the state Medicaid coverage provisions take precedence. Providers should consult the applicable state Medicaid manual for any state‑specific coverage rules that apply to this clinical policy.

Dosing, Concentration, and Coding Details

Maximum ALL daily dose

Maximum ALL daily dose2.5 mg/kg per day

Alternate maximum by body surface area75 mg/m2 per day

Typical dosing range (context)1.5 to 2.5 mg/kg (50 to 75 mg/m2) PO QD

Prior Authorization, Step Therapy, and Documentation Requirements

Prior Authorization

Prior Authorization Required

Prior authorization is required. Approval is contingent on meeting the clinical criteria in this policy, including diagnosis, prescriber specialty, and step therapy requirements where applicable.

Prior authorization required for Purixan (mercaptopurine oral suspension) and mercaptopurine oral suspension.
Approval depends on meeting specified criteria such as diagnosis of ALL or acute promyelocytic leukemia, prescription by or in consultation with an oncologist/hematologist, and applicable step therapy requirements.
For Illinois HIM requests, step therapy requirements do not apply as of 1/1/2026 per IL HB 5395.

Step Therapy

Prior Authorization and Step Therapy Notes

Step therapy and redirection provisions apply as stated in the criteria. Requests must document prior failure of mercaptopurine tablets before approval of the oral suspension unless tablets are contraindicated, cause clinically significant adverse effects, the member has a documented swallowing disorder or inability to swallow tablets, or the request falls under a state-specific oncology exception.

Approved Regimens and Maintenance Therapy

Maintenance — Line of therapy

Indication/line: Used as part of a combination chemotherapy maintenance regimen for acute lymphoblastic leukemia (ALL); typical maintenance therapy consists of daily 6-mercaptopurine with weekly methotrexate and monthly vincristine/prednisone pulses for 2–3 years.

Regimen	Dose / Frequency	Duration	Coverage Status
Daily 6-mercaptopurine with weekly methotrexate and monthly vincristine/prednisone pulses	6-mercaptopurine 1.5–2.5 mg/kg PO once daily (typical); maximum 2.5 mg/kg/day or 75 mg/m2/day	Maintenance for 2–3 years	Covered with criteria

Drug and Regimen Definitions

Purixan / mercaptopurine

Generic nameMercaptopurine (Purixan)

Drug class/descriptionNucleoside metabolic inhibitor and purine base analogue used in maintenance chemotherapy for ALL

Oral suspension concentration20 mg/mL

Formulation notesAvailable as an oral suspension useful for dose adjustments when tablets are not suitable

Typical maintenance regimen for ALL

Core maintenance regimenDaily 6-mercaptopurine

Concurrent weekly therapy

Clinical Background

Mercaptopurine (Purixan) is a purine base analogue and nucleoside metabolic inhibitor used as part of combination chemotherapy maintenance for acute lymphoblastic leukemia (ALL). It is administered orally and is typically included in maintenance regimens consisting of daily mercaptopurine with weekly methotrexate and monthly vincristine/prednisone pulses, continued for approximately 2–3 years.

Policy Updates and Revision Log

2025-07-14policy changeLatest

Added step therapy bypass for Illinois Health Insurance Marketplace per IL HB 5395.

2025-07-08policy change

Added redirection to generic mercaptopurine oral suspension and revised redirection to mercaptopurine tablets language from 'member must use' to 'failure of.'

2024-06-05administrative update

Updated Appendix E to include Mississippi.

Policy Summary

Payermhn

PolicyClinical Policy: Mercaptopurine (Purixan)

Policy CodePolicy CP.PHAR.447

Change TypeStep therapy and redirection updatesappendix and wording revisions

Effective Date03.01.20

Next Review Date

SourceLink

On This Page

Step therapy requires failure of mercaptopurine tablets unless contraindicated or other exceptions apply.
Members must use generic mercaptopurine oral suspension when appropriate; redirection to the generic oral suspension is allowed per policy updates.
States with regulations prohibiting certain redirections or step therapy in oncology settings are listed in Appendix E and override redirection/step therapy where applicable.

Documentation Required

Required Documentation and Basis for Denial

Provide supporting documentation with the prior authorization request. Requests that do not include required documentation or fail to demonstrate that the member meets the policy criteria may be denied.

Provider must submit documentation such as office chart notes, lab results, or other clinical information to support that the member meets all approval criteria.
Requests lacking documentation of diagnosis, prescriber specialty (oncologist/hematologist), prior failure of tablets (when required), or other required clinical information are at risk for denial.

Note

Coverage Decisions and Administration of Benefits

Coverage decisions and benefit administration are subject to the member's plan terms, conditions, exclusions, and limitations. This policy is a guide to medical necessity and does not guarantee payment.

Coverage decisions are governed by the evidence of coverage, certificate of coverage, policy, or contract of insurance and applicable state and federal requirements.
This clinical policy does not constitute a contract or guarantee regarding payment; benefit administration is subject to Health Plan-level administrative policies and procedures.

Note

Provider Obligations and Policy Binding

Providers submitting claims or providing services to members are bound by the terms of this policy. Unauthorized copying or distribution of this policy is prohibited.

Providers are expected to exercise professional medical judgment and are responsible for medical advice and treatment.
Where a contract exists, providers are bound by its terms; where no contract exists, providers and their representatives agree to be bound by this policy by providing services or submitting claims for payment.
Unauthorized copying, use, or distribution of this clinical policy or its information is strictly prohibited.

Monthly pulsesMonthly vincristine plus prednisone pulses

DurationTypically continued for 2–3 years as part of combination chemotherapy maintenance

2022-02-02policy update

Modified commercial approval duration to '12 months or duration of request, whichever is less' and previously revised redirection language to 'member must use.'