ModifiedCentenePolicy CP.PHAR.447

Mercaptopurine (Purixan) coverage

Defines medical necessity, prior authorization, and coverage criteria for Purixan (mercaptopurine oral suspension) including FDA-approved ALL treatment and specified off-label uses; applies to Centene-affiliated health plans and providers submitting requests.

Policy Summary

PayerCentene

PolicyMercaptopurine (Purixan) coverage

Policy CodePolicy CP.PHAR.447

Change TypeMaterial updates to approval durations and step therapy/redirection rulesadded NCCN-supported off-label criteria

Effective DateMar 1, 2020

Next Review Date

Key ActionSubmit prior authorization with documentation of diagnosis, oncologist/hematologist prescribing or consultation, evidence of tablet failure (or documented exception), and dosing support when applicable.

SourceLink

POLICY UPDATE CHANGES

Added criteria set for NCCN compendium supported off-label use in histiocytic neoplasms.

Revised initial approval duration for Medicaid/HIM from 6 to 12 months.

Modified commercial approval duration to '12 months or duration of request, whichever is less'.

Changed redirection/step therapy language: added requirement to fail mercaptopurine tablets before oral suspension except in specified exceptions; also added redirection to generic oral suspension and revised tablet redirection verbiage to 'failure of'.

Modified commercial approval duration from length of benefit to '12 months or duration of request, whichever is less'.

Added by-passing of redirection if state regulations do not allow step therapy in certain oncology settings.

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

Added criteria set for NCCN compendium supported off-label use in histiocytic neoplasms and revised initial approval duration for Medicaid/HIM from 6 to 12 months.

12 months

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Coverage Criteria

inv-01: Initial Therapy - ALL / APL

Covered when ALL of the following are met

A. Acute Lymphoblastic Leukemia or Acute Promyelocytic Leukemia (must meet all): 1. Diagnosis of 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) member has a documented swallowing disorder or inability to swallow tablets or capsules; (c) request is for treatment associated with cancer for a State with regulations against step therapy in certain oncology settings (see Appendix E) (Note: for Illinois HIM requests, the step therapy requirement does 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 are experienced, or request is for treatment associated with cancer for a State with regulations against step therapy (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).

inv-02: Initial Therapy - Histiocytic Neoplasms

Covered when ALL of the following are met

B. Histiocytic Neoplasms (off-label): 1. Diagnosis of Langerhans Cell Histiocytosis; 2. Prescribed by or in consultation with an oncologist; 3. Request is for first-line or subsequent therapy; 4. Prescribed in combination with vinblastine and prednisone; 5. Failure of mercaptopurine tablets unless one of the following applies: (a) mercaptopurine tablets are contraindicated or clinically significant adverse effects are experienced; (b) member has a documented swallowing disorder or inability to swallow tablets or capsules; (c) request is for treatment associated with cancer for a State with regulations against step therapy in certain oncology settings (see Appendix E) (Note: for Illinois HIM requests, the step therapy requirement does not apply as of 1/1/2026 per IL HB 5395); 6. Member must use generic mercaptopurine oral suspension unless contraindicated, clinically significant adverse effects are experienced, or request is for treatment associated with cancer for a State with regulations against step therapy (see Appendix E); 7. Dose is within FDA maximum limit for any FDA-approved indication or is supported by practice guidelines or peer-reviewed literature for the relevant off-label use (prescriber must submit supporting evidence). Prescribed regimen must be FDA-approved or recommended by NCCN.

inv-03: Continuation Therapy

Covered when ALL of the following are met

A. All Indications in Section I (continuation): 1. Member is currently receiving mercaptopurine oral suspension via the Centene benefit, or documentation supports current use of mercaptopurine oral suspension for a covered indication and the member has received it 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 are experienced, or request is for treatment associated with cancer for a State with regulations against step therapy (see Appendix E); 4. If request is for a dose increase, request meets one of the following: (a) new dose does not exceed 5 mg/kg or 75 mg/m2 per day; or (b) new dose is supported by practice guidelines or peer-reviewed literature for the relevant off-label use (prescriber must submit supporting evidence).

inv-04: Administrative and newly added clinical coverage criteria (extract)

Covered when ALL of the following administrative conditions are met

approval_duration: Commercial approvals limited to 12 months or duration of request, whichever is less; Medicaid/HIM initial approvals revised to 12 months.12 months

See prior authorization and drug-specific sections for details

redirection_and_step_therapy: Policy includes redirection to generic oral suspension; redirection to mercaptopurine tablets requires documented failure of the redirected product (language revised from 'member must use' to 'failure of'). State regulations may allow bypass of step therapy in certain oncology settings (see Appendix E); IL HIM bypass applies per IL HB 5395.N/A

Documentation must support application of redirection/step therapy rules; state-specific exemptions may apply

NCCN_off-label_histiocytic:

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

Coverage under this clinical policy is subject to all terms, conditions, exclusions, and limitations of the member’s coverage documents (for example, evidence of coverage, certificate of coverage, policy or contract of insurance) and to applicable state and federal law and Health Plan administrative policies. Where there is a conflict with state Medicaid provisions, the state Medicaid rules take precedence. The Health Plan may change, amend, or withdraw this clinical policy as allowed by law and contract.

Requests for non‑FDA approved indications that are not addressed in this policy will be denied unless the prescriber provides sufficient off‑label support per the referenced off‑label use policy. See CP.CPA.09 (Commercial), HIM.PA.154 (HIM/ICHRA), or CP.PMN.53 (Medicaid) for required evidence and documentation standards.

No explicit Not Medically Necessary conditions are listed in this extract. Any determinations of not medically necessary will follow the member’s benefit terms and applicable program rules described elsewhere in the coverage documents and policy.

Coding

Covered CPT Codesmixed

N/A	No procedural or billing codes listed in this section of the document

Affected codes (not specified in this section)mixed

affected codes

document references prior authorization and approval durations applying to affected codes (exact codes not listed in this extract)

Maximum maintenance dose — mercaptopurine

Maximum maintenance dose2.5 mg/kg/day or 75 mg/m2/day

Typical dosing range (ALL)1.5 to 2.5 mg/kg (50 to 75 mg/m2) PO once daily

ContextDose limits apply to maintenance therapy for acute lymphoblastic leukemia as listed in Dosage and Administration.

Provider Actions & Authorization

Prior Authorization

Prior Authorization Required

Prior authorization is required. Requests must include documentation of the member’s diagnosis and that the drug is prescribed by or in consultation with an oncologist or hematologist. Prior authorization also requires demonstration of failure of mercaptopurine tablets when step therapy applies (see step therapy rules below) unless tablets are contraindicated, cause clinically significant adverse effects, the member has a documented swallowing disorder, or the request is for treatment associated with cancer in a State with regulations prohibiting step therapy in certain oncology settings (see Appendix E).

Affected products: Purixan (mercaptopurine oral suspension) and mercaptopurine oral suspension generics
Prescriber requirement: oncologist or hematologist prescribing or consultation

Documentation Required

Provider must submit supporting clinical documentation (e.g., office chart notes, lab results, swallowing assessment, prior medication trials, and any literature supporting off‑label dosing) showing that the member meets all approval criteria. Failure to provide adequate documentation may result in denial.

Background

Mercaptopurine is a purine analogue nucleoside metabolic inhibitor used in maintenance chemotherapy for acute lymphoblastic leukemia (ALL). Dosing is weight‑ or body‑surface‑area–based and treatment can cause myelosuppression. Genetic factors such as TPMT polymorphisms and interactions with other drugs can affect mercaptopurine metabolism and may require dose adjustments; prescribers should monitor labs and clinical status per standard oncology practice.

Definitions

ALL — Definition and indication

ALL definitionAcute lymphoblastic leukemia (ALL)

Indication statusFDA‑approved indication for mercaptopurine (Purixan) maintenance therapy

Usage notePolicy criteria reference initial and continuation therapy requirements for ALL

Initial Therapy Criteria

inv-22: Initial Therapy — Initial authorization criteria

Initial authorization — Covered when ALL of the following are met

Initial therapy criteria: 1. Diagnosis of a covered condition as specified in the Initial Therapy sections (e.g., ALL, acute promyelocytic leukemia off‑label, or NCCN‑supported histiocytic neoplasm); 2. Medication prescribed by or in consultation with an oncologist or hematologist as required in the relevant indication; 3. Failure of mercaptopurine tablets is documented unless an exception applies (contraindication/adverse effects, documented swallowing disorder, or state regulation prohibiting step therapy); 4. Member must use generic mercaptopurine oral suspension unless contraindicated or clinically significant adverse effects are experienced or state regulations prohibit step therapy; 5. Dosing is within specified limits (≤ 2.5 mg/kg or 75 mg/m2/day for initial therapy) or is supported by practice guidelines/peer‑reviewed literature with supporting evidence submitted by the prescriber.

inv-23: Initial therapy duration updates

Covered when ALL of the following are met

initial_duration_medicaid_him: Initial approval duration for Medicaid/HIM revised from 6 months to 12 months.

Continuation Therapy Criteria

inv-24: Continuation Therapy — Continuation therapy requirements

Covered when ALL of the following are met

Continuation criteria: 1. Member is currently receiving Purixan via the Centene benefit or documentation supports current use for a covered indication with at least 30 days of therapy; 2. Member is responding positively to therapy; 3. Member must use generic mercaptopurine oral suspension unless contraindicated or clinically significant adverse effects are experienced or state regulations prohibit step therapy; 4. Dose increase requests must meet one of the following: (a) new dose does not exceed 5 mg/kg or 75 mg/m2 per day; or (b) new dose is supported by practice guidelines or peer‑reviewed literature (prescriber must submit evidence).

inv-25: Continuation therapy duration

Covered when ALL of the following are met

duration_limit: Continuation/renewal approvals adhere to the commercial cap of 12 months or duration requested, and Medicaid/HIM continuation aligns with the revised 12‑month initial duration; requests exceeding approved durations may be denied or require additional justification.

Step Therapy & Redirection Rules

Step	Requirement / Description	Exceptions
1
Initial step: Failure of mercaptopurine tablets required prior to approval of mercaptopurine oral suspension (generic) — provider must document prior trial and failure of tablets.
Tablets are not required if: (a) tablets are contraindicated or cause clinically significant adverse effects; (b) member has a documented swallowing disorder or inability to swallow tablets/capsules; (c) request is for treatment associated with cancer in a State with regulations prohibiting step therapy in certain oncology settings (see Appendix E). Note: Illinois HIM requests are exempt from the step therapy requirement per IL HB 5395 effective 1/1/2026.

Redirection / Step	Policy Action	State or product-specific notes
Redirection to generic oral suspension
Requests are redirected to generic mercaptopurine oral suspension when appropriate; redirection to mercaptopurine tablets now requires documentation of failure of the redirected product (language revised from 'member must use' to 'failure of').
State regulations that prohibit step therapy in oncology may allow bypass of redirection (see Appendix E). Appendix D/E lists states with oncology step-therapy prohibitions and notes (e.g., LA, MS, NV, OH, OK, PA, TN, TX); IL HIM bypass per IL HB 5395 noted separately.

Quantity Limits & Product

Purixan (mercaptopurine oral suspension) — product details

ProductPurixan (mercaptopurine oral suspension)

Concentration20 mg/mL (2,000 mg/100 mL)

Quantity limitsSpecific quantity limits not listed in this document

Formulation noteGeneric mercaptopurine oral suspension referenced for redirection/step therapy

Site of Care

Note

Site of care: none specified in this extract

No site-of-care restrictions are specified in this portion of the policy; site-of-care limitations are not addressed in the extracted sections.

Refer to the full policy for any site-of-care rules outside this extract.

Note

Site-of-care / infusion center: state step therapy exemptions may apply

State exemptions permit bypassing step therapy in certain oncology settings; while site-of-care limitations are not specified in this extract, state-specific regulations (see Appendix E) may affect whether step therapy/redirection applies.

Examples include added step therapy bypass for IL HIM per IL HB 5395 and other state entries listed in Appendix E.
Document applicable state exemptions when requesting a bypass.

Policy Summary

PayerCentene

PolicyMercaptopurine (Purixan) coverage

Policy CodePolicy CP.PHAR.447

Change TypeMaterial updates to approval durations and step therapy/redirection rulesadded NCCN-supported off-label criteria

Effective DateMar 1, 2020

Next Review Date

SourceLink

On This Page

Step Therapy

Step Therapy (tablet → suspension)

Step therapy requires failure of mercaptopurine tablets before approval of mercaptopurine oral suspension, unless the patient meets an exception: tablets are contraindicated or cause clinically significant adverse effects; the member has a documented swallowing disorder or inability to swallow tablets/capsules; or the request is for treatment associated with cancer in a State with regulations that prohibit step therapy in certain oncology settings (see Appendix E). For Illinois HIM requests, the step therapy requirement does not apply per IL HB 5395 (effective 1/1/2026).

Member must typically try generic mercaptopurine tablets and demonstrate failure prior to oral suspension
Exceptions: contraindication, adverse effects, documented swallowing disorder, state-specific oncology step therapy prohibitions (Appendix E)

Step Therapy

Redirection & State Exemption Documentation

The policy includes redirection/step therapy rules requiring use of generic mercaptopurine oral suspension when available unless contraindicated or clinically significant adverse effects occur, or when state regulations for oncology step therapy allow bypass. Recent updates add redirection to generic oral suspension and changed language to require demonstration of failure of tablets (rather than 'member must use') before suspension is approved. Documentation must support any redirection or claimed exemption under state law.

Redirection: member must use generic mercaptopurine oral suspension unless contraindicated or adverse effects occur, or state oncology step therapy rules allow bypass
State exemptions: Appendix E lists states where oncology step therapy is prohibited or limited; prescribers must document applicability (for example, IL HIM per IL HB 5395)