CurrentColorado Rocky Mountain Health PlansPolicy N/A

Vowst (fecal microbiota spores, live-brpk) prior authorization

Defines prior authorization and medical necessity criteria for Vowst to prevent recurrent Clostridioides difficile infection (rCDI) in adults, and who may prescribe it within Colorado Rocky Mountain Health Plans' clinical pharmacy programs.

Policy Summary

PayerColorado Rocky Mountain Health Plans

PolicyVowst (fecal microbiota spores, live-brpk) prior authorization

Policy CodePolicy N/A

Change TypeRevised clinical criteria

Effective DateOct 1, 2025

Next Review DateJul 1, 2025

Key ActionObtain prior authorization and document rCDI diagnosis, prior Rebyota failure/contraindication/intolerance, completion of at least 10 days of specified antibiotics, and patient age ≥18.

SourceLink

POLICY UPDATE CHANGES

Updated antibiotic course requirement and lowered the number of required recurrent CDI in prior updates; added clarifying note that coverage of Rebyota may be subject to additional benefit and coverage review requirements.

18+minimum patient age for coverage

1+required prior CDI recurrences

1 moauthorization duration

10 daysminimum antibiotic course

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Coverage Criteria for Vowst

Initial Therapy

Vowst will be approved when ALL of the following are met:

Initial Authorization for Vowst

Diagnosis of rCDI: Presence of diarrhea defined as >=3 loose bowel movements within a 24-hour period for 2 consecutive days AND a positive stool test for C. difficile toxinsee threshold: diarrhea frequency
Age: Patient is 18 years of age or older18+
Prior recurrences: Patient has had one or more recurrence(s) of CDI following an initial episode of CDI1+
Prior therapy with Rebyota: Patient has had a failure, contraindication, or intolerance to Rebyota
Coverage of Rebyota may be subject to additional benefit and coverage review requirements
Antibiotic therapy: Patient completed at least 10 days of oral vancomycin or fidaxomicin (Dificid) 2 to 4 days prior to initiating Vowst10 days
Stool control: Previous episode of CDI is under control (e.g., <3 unformed/loose stools/day for 2 consecutive days)
Pre-dose magnesium citrate: Patient will drink magnesium citrate on the day before and at least 8 hours prior to first dose of Vowst
Prescriber type: Prescribed by or in consultation with a gastroenterologist or infectious disease specialist

See coverage.criteria_sets.Initial Therapy: Refer to the Coverage module for the full AND logic of initial therapy requirements

Coverage of Vowst is subject to applicable state mandates, federal regulatory requirements, and the specifics of the member’s benefit plan; these factors may modify or limit coverage determinations. Other internal policies and utilization management programs may also apply and could affect prior authorization, approval, or payment for therapy.

Initial Therapy Requirements

Initial therapy requirements

Initial approval requires meeting all listed criteria.

See coverage.criteria_sets.Initial Therapy: Refer to the Coverage module for the full AND logic of initial therapy requirements

Provider Actions and Prior Authorization

Prior Authorization

Prior Authorization Required

Prior authorization is required and will be approved when all listed clinical criteria are met. Authorization will be issued for 1 month. State mandates, federal requirements, and member-specific benefits may affect coverage.

Authorization will be issued for 1 month
State mandates, federal regulatory requirements, and member-specific benefit plans may impact coverage

Note

Rebyota Requirement

Requires prior failure, contraindication, or intolerance to Rebyota before Vowst will be approved. Coverage of Rebyota may be subject to additional benefit and coverage review requirements.

Patient must have had a failure, contraindication, or intolerance to Rebyota for prevention of rCDI

Clinical Definitions and Coding Notes

inv-03: Diarrhea frequency

Threshold>= 3 loose bowel movements within a 24-hour period

Durationfor 2 consecutive days

ContextPart of diagnosis criteria for recurrent C. difficile infection (rCDI)

Definitions Relevant to rCDI and Vowst

inv-09: Recurrent Clostridioides difficile infection (rCDI)

Definition of rCDIPresence of diarrhea defined as passage of 3 or more loose bowel movements within a 24-hour period for 2 consecutive days

Diagnostic confirmationPlus a positive stool test for Clostridioides difficile toxin

Use in authorizationRequired component of the initial authorization criteria for Vowst

inv-10: Stool control prior to Vowst

Stool control definitionPrevious episode is under control defined as fewer than 3 unformed/loose stools per day (Bristol Stool Scale type 6-7)

Duration for controlfor 2 consecutive days

Step Therapy Requirements

Step	Requirement	Notes
{"text":"1","status":""},{"text":"Must have tried and had failure, contraindication, or intolerance to Rebyota","status":"covered"},{"text":"Coverage of Rebyota may be subject to additional benefit and coverage review requirements","status":""}
{"text":"","status":""},{"text":"Documentation must show prior Rebyota failure, contraindication, or intolerance as part of prior authorization","status":""},{"text":"Requirement added in 12/2023; clarifying note regarding Rebyota coverage added 7/2025","status":""}

Background on Vowst

Vowst (fecal microbiota spores, live‑brpk) is indicated to prevent recurrence of Clostridioides difficile infection (CDI) in adults following antibacterial treatment for recurrent CDI. Prior authorization is required; when approved, authorization will be issued for 1 month. Providers should follow the policy’s clinical thresholds and documentation requirements when requesting prior authorization.

Documentation Required

Required Documentation and Triggers for Denial

Documentation must include evidence of rCDI diagnosis, patient age, prior CDI recurrence history, prior Rebyota status, antibiotic treatment completion, stool toxin test results, and prescribing clinician specialty. Triggers for denial include insufficient documentation of these elements or failure to meet the clinical criteria below.

Evidence of rCDI diagnosis: diarrhea defined as ≥3 loose bowel movements within 24 hours for 2 consecutive days AND a positive stool test for C. difficile toxin
Patient age ≥ 18 years
Documentation of one or more recurrence(s) of CDI following an initial episode
Documentation of failure, contraindication, or intolerance to Rebyota
Evidence patient completed at least 10 days of oral vancomycin or fidaxomicin 2–4 days prior to initiating Vowst
Evidence prior episode of CDI is under control (e.g., <3 unformed/loose stools/day for 2 consecutive days)
Medication instructions: patient will drink magnesium citrate on the day before and ≥8 hours prior to first Vowst dose
Prescribed by or in consultation with a gastroenterologist or infectious disease specialist
Triggers for denial: failure to document rCDI diagnosis (diarrhea definition and positive toxin test), age <18 years, no documented prior CDI recurrence, no documentation of Rebyota failure/contraindication/intolerance, no documentation of required antibiotic course completion, or lack of required prescriber specialty