Health Net mercaptopurine (Purixan) Coverage Update

Coverage Criteria

inv-01: Initial Therapy — Initial Approval — Purixan is medically necessary when ALL of the following are met

Initial Approval — Purixan is medically necessary when ALL of the following are met:

Diagnosis of acute lymphoblastic leukemia (ALL) or acute promyelocytic leukemia (off-label)

Prescriber: Prescribed by or in consultation with an oncologist or hematologist

Tablet contraindication or intolerance: Mercaptopurine tablets are contraindicated or clinically significant adverse effects are experienced

Step therapy exceptions: Failure of mercaptopurine tablets OR documented swallowing disorder or inability to swallow tablets OR state oncology step-therapy prohibitions apply

For Illinois HIM requests, step therapy requirements do not apply as of 1/1/2026 per IL HB 5395

Product redirection: Member must use generic mercaptopurine oral suspension unless contraindicated, clinically significant adverse effects occur, or state regulations prohibit redirection in oncology settings (see Appendix E)

Dose limit: Dose does not exceed 2.5 mg/kg or 75 mg/m2/day<=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

inv-02: Continuation Therapy — Continued Therapy — Purixan continuation is medically necessary when ALL of the following are met

Continued Therapy — Purixan continuation is medically necessary when ALL of the following are met:

Current therapy: Member is currently receiving Purixan via Centene benefit or has documentation of at least 30 days of mercaptopurine oral suspension therapy

Clinical response: Member is responding positively to therapy

Dose increase: If request is for a dose increase, new dose must not exceed 5 mg/kg or 75 mg/m2/day OR the increase must be supported by practice guidelines or peer-reviewed literature (prescriber must submit supporting evidence)

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

When a member is covered by a state Medicaid program and a conflict exists between this clinical policy and state Medicaid coverage provisions, state Medicaid coverage provisions take precedence. Providers and reviewers should follow the applicable state Medicaid manual for specific coverage rules.

Requests for uses that are non‑FDA approved and are not supported by sufficient clinical documentation per the referenced off‑label use policies will be considered not medically necessary and will be denied. Providers must submit office chart notes, laboratory results, or other clinical evidence to demonstrate efficacy and safety when seeking coverage for off‑label indications.

Coding and Dose Limits

Codes referencedmixed

N/A	No explicit CPT/HCPCS/ICD-10 codes listed in this portion of the document

Dose limits — Initial and continued therapy

Initial therapy dose limitDose does not exceed 2.5 mg/kg or 75 mg/m2/day

Continued therapy dose increase limitNew dose must not exceed 5 mg/kg or 75 mg/m2/day unless supported by practice guidelines or peer‑reviewed literature

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

Provider Actions and Authorization

Prior Authorization

Prior Authorization Required

Prior authorization is required. Approval is conditional on meeting the criteria listed in this policy, including diagnosis, prescriber specialty, and failure or contraindication to alternative formulations when applicable.

Prior authorization required prior to initiation of therapy.
Approvals are contingent on submission of required clinical documentation supporting all approval criteria.

Prior Authorization

Prior Authorization and Approval Duration

Approval durations and prior authorization timing vary by line of business: Medicaid/HIM approvals are granted for 6 months; Commercial approvals are granted for 12 months or the duration of request, whichever is less. Prior authorization should be requested before dispensing.

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

Initial Therapy Criteria

inv-20: Initial Therapy — Initial authorization requirements (duplicate/alternate placement of initial criteria)

Initial Approval — Purixan is medically necessary when ALL of the following are met:

Diagnosis of ALL or acute promyelocytic leukemia

Prescriber: Prescribed by or in consultation with an oncologist or hematologist

Tablet step: Mercaptopurine tablets must be tried and failed unless contraindicated, patient unable to swallow tablets, or state oncology step-therapy prohibitions apply

IL HIM bypass per IL HB 5395

Redirection to generic suspension: Member must use generic mercaptopurine oral suspension unless contraindicated, clinically significant adverse effects occur, or state regulations prohibit redirection

Continuation Therapy Criteria

inv-21: Continuation Therapy — Continued therapy criteria (duplicate/alternate placement of continuation criteria)

Continued Therapy — Purixan continuation is medically necessary when ALL of the following are met:

Duration on therapy: Member has received mercaptopurine oral suspension for at least 30 days prior to request>=30 days

Clinical benefit: Member is responding positively to therapy

Step Therapy and Redirection

Step	Requirement	Exceptions / State notes
1	Trial of mercaptopurine tablets preferred; member must use generic mercaptopurine oral suspension unless contraindicated or clinically significant adverse effects are experienced.	Redirection to suspension allowed; states with regulations prohibiting redirection in certain oncology settings (see Appendix E) may override redirection.
Failure criteria	Failure or intolerance to mercaptopurine tablets, or tablets are contraindicated, or documented swallowing disorder / inability to swallow tablets.	Appendix E lists states where step-therapy/redirection is prohibited in certain oncology settings (examples: FL, GA, IA, LA, MS, NV, OH, OK, PA, TN, TX).
Dose limit	Dose must not exceed 2.5 mg/kg or 75 mg/m2/day for initial therapy.	Approval duration: Medicaid/HIM 6 months; Commercial 12 months or duration of request, whichever is less.

Step	Redirection / Bypass	State / Oncology-specific allowance
1	Policy permits redirection between generic mercaptopurine tablets and generic oral suspension; wording updated to allow redirection to generic oral suspension.	Added allowance: Illinois HIM requests bypass step therapy per IL HB 5395 effective 1/1/2026.
When redirection applies	Member must use generic oral suspension unless contraindicated, clinically significant adverse effects occur, or state regulations prohibit redirection in oncology settings.	Appendix E enumerates states with protections against redirection in certain oncology settings; template updated over review cycles to reflect state additions and clarifications.
Operational notes	Commercial approval duration modified to 12 months or duration of request, whichever is less; redirection language revised during 2022–2025 reviews including addition of redirection to suspension and IL bypass.	Documented annual review history and Appendix E updates reflect ongoing state-level modifications to redirection/step therapy rules.

Background

Mercaptopurine is a purine analogue nucleoside metabolic inhibitor (a thiopurine antimetabolite) used primarily as part of multi‑agent chemotherapy maintenance for acute lymphoblastic leukemia (ALL). Maintenance regimens typically include daily mercaptopurine (oral) combined with weekly methotrexate and periodic vincristine and prednisone over a prolonged course; individual dosing and toxicity are affected by TPMT polymorphisms and drug–drug interactions.

Definitions

Purixan / mercaptopurine oral suspension — product identification

Brand and generic namePurixan (mercaptopurine) oral suspension

Drug classNucleoside metabolic inhibitor / purine analogue

Formulation strengthOral suspension: 2,000 mg/100 mL (20 mg/mL)

ALL — definition of Acute lymphoblastic leukemia

DefinitionALL (acute lymphoblastic leukemia): a hematologic malignancy referenced in the policy as the primary covered indication for mercaptopurine

Clinical contextNCCN notes lymphoblastic lymphoma is indistinguishable from ALL and treated with ALL‑like regimens

Quantity Limits

Purixan (mercaptopurine) oral suspension — quantity limit

Quantity limit specifiedNot specified

Formulation unit20 mg/mL oral suspension (2,000 mg/100 mL)

ImplicationNo per‑member quantity restriction listed in this policy—use dosing and clinical criteria to determine quantity

OpenPayer

Mercaptopurine (Purixan) coverage