A strategic framework for pharmacists to successfully appeal prior authorization denials through evidence-based documentation, proper coding, and systematic follow-up to ensure patient medication access.
A woman aged 32 years with severe plaque psoriasis calls the specialty pharmacy, hopeful about starting bimekizumab (Bimzelx; UCB). Multiple topical therapies have failed, but her dermatologist prescribed the biologic after conventional systemics proved ineffective. One week later, she receives a denial letter that says, "Medical necessity not established." Her treatment is delayed, her disease progresses, and her quality of life deteriorates while she waits for an appeal.
This scenario plays out thousands of times daily across the US. Nearly 53 million prior authorization requests were submitted to Medicare Advantage insurers in 2024, with approximately 4.1 million denied.1 The burden is particularly heavy for specialty medications, in which some studies report initial denial rates approaching 51% for complex biologic requests.2
The good news: Among prior authorization denials that were appealed, 81.7% saw the initial denial fully or partially overturned.1 Yet only 11.5% of denied prior authorization requests in Medicare Advantage were appealed in 2024.1 This represents a critical gap where clinical pharmacists can make a profound difference.
Prior authorization denials typically fall into 3 categories: clinical (medical necessity not established), administrative (paperwork issues), and coverage-based (formulary restrictions). Understanding which type of denial you face determines your appeal strategy.
Timeline requirements vary by payer. Standard appeals typically allow 15 to 30 days, although expedited appeals for urgent situations must be processed within 24 to 72 hours.3,4 Understanding these timelines is critical for ensuring appeals are submitted promptly.
Through years of managing specialty pharmacy prior authorizations, I have observed recurring errors that result in preventable denials.
Using Wrong or Inappropriate Diagnosis Codes: Incorrect International Statistical Classification of Diseases, Tenth Revision (ICD-10) coding is one of the most common, and most preventable, causes of denial. Payers use diagnosis codes to determine medical necessity, and even minor coding errors trigger automatic denials.
For example, a patient with severe persistent asthma requiring dupilumab (Dupixent; Sanofi, Regeneron) should have the appropriate code for severe persistent asthma, uncontrolled (J45.50) rather than unspecified asthma. Many payers require documentation of disease severity and control status, and nonspecific codes result in denial even when treatment is appropriate.
Before submitting, best practice is to verify that ICD-10 codes are current, specific, aligned with FDA-approved indications and payer medical policies, and supported by documentation in the medical record.
Failing to Include Relevant Clinical Documents: Many denials occur because submitted documentation fails to demonstrate medical necessity. Commonly missing items include recent laboratory results showing disease severity, progress notes documenting treatment failures with objective measures, pharmacy claims proving step therapy completion, and specialist consultation notes for complex cases.
Best practice is to create standardized documentation checklists for common therapeutic areas. Implement quality checks before submission to ensure completeness.
Not Evaluating Step Therapy Requirements: Perhaps the most frustrating preventable denial is failure to verify step therapy requirements before submission. Step therapy requirements vary dramatically across payers and plans, and many do not consider the use of drug samples or manufacturer-assisted drugs as having met prior therapy requirements.
Best practice is to check the patient's specific formulary, review payer medical policies, verify prior therapy trials through pharmacy claims, and evaluate whether step therapy exceptions are appropriate before submitting.
Review the denial letter to identify the specific reason, note deadlines, and determine denial type. Gather baseline information, including medication history, relevant labs, and prior therapy documentation.
Document medical necessity and include specific diagnosis codes with supporting clinical data, disease severity markers, and quality-of-life impact. Provide a comprehensive treatment history with objective evidence of failure for each prior therapy: Quantify inadequate response with lab values, imaging, or validated scores.
Support with evidence by citing clinical guidelines with specific recommendations and strength of evidence. Include pivotal trials, real-world evidence, and comparative effectiveness data. For off-label use, provide compendia listings or published case series.
The opening should include the patient identifier, requested medication, diagnosis with ICD-10 codes, and clear appeal statement. The body should be organized into numbered sections: (1) Clinical background with disease severity, (2) Prior treatment history with objective failure evidence and specific data points, (3) Medical necessity for requested agent with guideline support and unique benefits, and (4) Risk of denial, including clinical consequences and quality-of-life impact. Finally, the closing should request approval with a specific quantity and duration. Offer to provide additional information.
Keep it to 1 to 2 pages. Use medical terminology appropriately but explain clearly. Include specific data with dates and values. Maintain a professional, evidence-based tone. Bold key points for easy scanning.
Organize attachments: prescriber's letter, clinical guidelines (highlighted), key publications, lab results and imaging, medication history, progress notes, and compendia excerpts for off-label uses.
Submit through appropriate channels (fax, online portal, or certified mail). Document submission details and set calendar reminders. Call within 48 hours to confirm receipt. Make weekly status checks and escalate if delayed.
Create systems for efficiency, including the following:
Mallory M. Ashmore, PharmD, BCPS, is a clinical pharmacy specialist in specialty pharmacy at the University of Mississippi Medical Center in Jackson, Mississippi. She specializes in rare disease management across multiple therapeutic areas, including pulmonology, rheumatology, and gastroenterology.
Ashmore serves on advisory boards for UCB and the PAN Foundation Healthcare Provider Advisory Council. These relationships did not influence the content of this article.
Prior authorization denials need not be insurmountable barriers to patient care. The high overturn rate on appeal (over 80% for Medicare Advantage plans) demonstrates that many denials lack clinical merit and can be successfully challenged with proper documentation and advocacy.1,5
Clinical pharmacists bring unique value to this process, combining pharmacotherapy expertise with understanding of clinical guidelines, evidence-based medicine, and the health care system. By approaching appeals strategically with thorough documentation, compelling clinical rationale, and persistent follow-up, pharmacists become indispensable patient advocates.5
Every successful appeal represents a patient accessing needed therapy, potentially preventing disease progression and serious complications. Start building your appeal toolkit today. Document your successes to demonstrate value and share strategies with colleagues. Most importantly, remember that behind every prior authorization denial is a patient waiting for treatment, and your expertise and advocacy can make all the difference in their care.
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