June 6, 2026 · ~10 minute read

Step therapy appeals: how to win the fail-first fight in 2026

I am at my desk in San Diego with a cold coffee and a stack of plan documents, and the scene I keep running into goes like this. A patient has been on a drug that works. Their plan changes in January, or they age into Medicare Advantage and pick a new plan during the annual election period. The pharmacy runs the claim. Rejected. The new plan says the patient has to try a cheaper drug first. Sometimes two. The note from the gastroenterologist or neurologist saying “this works, do not change it” gets treated like a suggestion.

I trained in Health Informatics, which means I spent a lot of time looking at how data flows between providers, plans, and PBMs. Step therapy is one of those policies where the data the plan needs exists, it just does not get to the right desk at the right time. The system is not designed to surface it. It is designed to bounce requests back and let attrition do the work. This post is about pushing the right paper into the right inbox, with the right citations, in the right window. I will focus on MA, but most of this applies to commercial plans too.

What step therapy actually is, and how it differs from prior auth

Step therapy is a plan policy that requires you to try, and fail, one or more cheaper or formulary-preferred drugs before the plan will cover the drug your prescriber wrote. Plans call it different things: fail-first, protocol override, step edit. The federal definition reads, roughly, as a utilization management policy that begins treatment with the most preferred or cost-effective therapy and progresses to others if medically necessary.

Prior authorization is the broader category. Step therapy is a specific kind of prior auth that says, “yes, we might cover this drug, but only after you have documented failure on Drug A, then maybe Drug B.” A plain prior auth might be satisfied by a diagnosis code and a chart note. A step therapy denial usually cannot be, because the plan is not asking whether the drug is appropriate, it is asking whether you have served your time on the cheaper one.

Think of it as a procedural gate on top of a clinical question. Your appeal has to clear both.

The 2019 CMS expansion to MA, in plain English

Before 2019, MA plans could not impose step therapy on Part B drugs at all. Part B drugs are the ones administered in a clinic or infusion center: rheumatology biologics, certain oncology infusions, some eye injections. CMS reversed that prohibition in the final rule published April 16, 2019 at 84 FR 15680, and the operating regulation now sits at 42 CFR 422.136, effective May 23, 2019. (Federal Register, 42 CFR 422.136)

Six years in, MA plans can impose step therapy for both Part B and Part D drugs. The rule has guardrails. It applies only to new starts, with at least a 365-day lookback. Protocols must be approved by the plan's P&T committee. Off-label drugs can only be required as a step if widely accepted clinical literature supports that use.

I mention this because patients and some prescribing offices still operate on the pre-2019 mental model where Part B drugs were untouchable. They are not. The question is how to get around the policy.

The exception process is your primary appeal lever

The first place to go after a step therapy denial is the exception process. For Part D drugs, the controlling regulation is 42 CFR 423.578. (42 CFR 423.578) For Part B drugs under MA, the exception flows through the standard organization determination and reconsideration framework in 42 CFR Part 422, with timing mirroring Part D.

Under 423.578, the plan must grant a formulary exception when the prescriber submits a supporting statement showing that the preferred or required drugs would not be as effective, would have adverse effects, or both. For step therapy, that statement is where you make your case that the patient cannot or should not have to step through.

The timing matters. The plan must respond to a standard exception request no later than 72 hours after receipt of the prescriber's supporting statement, and to an expedited request within 24 hours. If the statement does not come in within 14 calendar days of the initial request, the plan still has to decide within 72 hours of the end of that window.

The 24-hour expedited clock is the one you want when a treatment gap is medically risky. For biologics, MS DMTs, and most oncology drugs, expedited is appropriate. The prescriber has to indicate that waiting could seriously jeopardize the patient's life, health, or ability to regain maximum function. Most will sign that for these drug categories.

The patient, the patient's authorized representative, or the prescriber can request the exception. You do not have to wait for the doctor's office to initiate.

The medical necessity letter for step therapy is structured differently

I have written about medical necessity letters a few times now, and the refrain holds: the letter is the lever. For step therapy, the structure is different from a generic prior auth letter.

A generic prior auth letter says “patient has Condition X, prescribing Drug Y, here is why Drug Y is appropriate.” That does not answer the question the plan is asking in a step therapy denial. The plan is not asking “is Drug Y appropriate.” It is asking “why can't you use Drug A or Drug B first.”

So the letter has to walk through each required step, by name, and give a specific clinical reason this patient cannot use it. The structure I see work:

1. One paragraph stating the patient, the condition, the prescribed drug, and the requested exception.
2. A list, by name, of each formulary alternative the plan would require as a step.
3. For each alternative, a one to three sentence clinical reason this patient cannot use it. Examples: documented prior trial from another insurer with dates and outcome, contraindication based on lab values or comorbidity, known drug-drug interaction with another medication the patient cannot stop, history of adverse effect from the same drug class.
4. A paragraph stating why the prescribed drug is medically necessary for this patient, citing peer-reviewed evidence or guideline-level recommendations for the specific indication.
5. A short closing pointing the plan to 42 CFR 423.578 and requesting an expedited determination if appropriate.

The letter does not need to be long. Two pages is fine. One page is often better. What it needs is to address every required step by name. A letter that says “patient needs Humira” with no engagement with the plan's required steps almost always gets denied at Level 1. A letter that walks through each of Skyrizi, Rinvoq, and Stelara with a specific reason for this patient gets a much better outcome.

Documentation that wins step therapy exceptions

The letter is the framework. The attachments carry the weight. The exception requests I have seen succeed at Level 1 generally include:

• Prior trial documentation. Clinic notes showing the patient was on Drug A from date X to date Y with a specific outcome. “Patient on adalimumab from March 2023 to November 2023 with secondary loss of response, anti-drug antibody titer documented.” Vague references to “tried it before” do not move the needle.
• Contraindication evidence. Lab values, comorbidities, drug interactions. If the patient cannot take a TNF inhibitor because of a prior demyelinating event, attach the neurology note.
• Peer-reviewed evidence for the prescribed drug in the patient's specific indication, not just the drug class.
• Prescriber specialty credentials. A letter from a board-certified gastroenterologist requesting a Crohn's biologic carries more weight than the same letter from primary care, fairly or not.
• Prior trials documented under a previous insurer, if the patient is transferring. Several state laws and a growing number of plan policies require recognition of those.

If you have to choose between a longer letter and better attachments, choose better attachments.

The prescriber-office failure mode and how to work around it

The most common failure mode I see is procedural. The prescriber's office says “we'll handle it” and then does not, for two weeks, and by then the patient is out of medication and the appeal window is shrinking.

I am not blaming the office. They do fifteen of these a day and their staff is not paid for the time. But the patient cannot afford to wait.

What I tell people to do, in order:

1. Within 48 hours of the denial, contact the prescriber's office in writing. Email is fine. Ask for the exception to be submitted within 48 hours and for a copy of the supporting statement.
2. If you do not have confirmation within five business days, call and ask to speak with the prescriber directly, or the practice manager. A polite “the appeal clock is running” call often surfaces that the request is sitting in someone's queue.
3. If the office still has not moved by day seven, file the exception yourself. The patient can initiate under 42 CFR 423.578. The plan still needs a prescriber supporting statement, but you start the response clock and the plan will reach out to the prescriber directly.

The pattern I want to break is the one where the patient waits silently for the doctor's office, the office waits silently for the patient, and the plan wins by default.

State step therapy reform laws, and where they stop

A growing number of states have passed step therapy reform laws. The count moves around depending on how you count partial reforms, but as of 2026 somewhere in the range of two dozen states have enacted laws constraining how insurers impose step therapy. New Jersey's took effect January 1, 2026. (Step Therapy Legislation by State)

These laws typically require plans to publish a clear exception process, set response timelines often shorter than federal Medicare ones, accept documented prior trials from previous insurers, and exempt patients with documented contraindications or prior adverse reactions.

The catch is what they apply to. They generally cover state-regulated commercial plans: individual market, small group, fully insured employer plans, sometimes state Medicaid. They do not apply to self-funded employer plans, which are governed by ERISA (roughly 100 million Americans), and they do not apply to Medicare Advantage, which is federally regulated.

So if you are on an MA plan, state law is not your tool. The federal exception process and the MA appeals ladder are. If you are on an ACA marketplace plan or a fully insured employer plan in a state with a reform law, invoke it explicitly in the letter. The Crohn's and Colitis Foundation, the National Multiple Sclerosis Society, and the National Psoriasis Foundation each maintain state-by-state trackers worth pulling before drafting.

Drug categories where step therapy denials are most common in 2026

A non-exhaustive list of where I see these denials most often:

• Biologics for autoimmune disease (Crohn's, UC, RA, psoriasis, psoriatic arthritis, axial spondyloarthritis, atopic dermatitis). Many plans now require a biosimilar adalimumab or infliximab as a step before a newer agent. The case usually turns on prior trial or documented loss of response.
• GLP-1s for diabetes and weight management. Plans frequently require metformin, a sulfonylurea, or another GLP-1 as a step. Coverage for weight-management indications has gotten messier in 2026, and many plans simply exclude the indication, which is a different fight.
• CGRP migraine preventives. Aimovig, Emgality, Ajovy, Vyepti, and the oral gepants. Plans often require documented failure on two or more older preventives.
• MS disease-modifying therapies. Plans increasingly require a step through a generic or platform DMT before covering a higher-efficacy agent. The literature on going straight to higher-efficacy in newly diagnosed patients has strengthened and is worth citing.
• Specialty oncology and hepatitis C round out the list, with the caveat that oncology denials often involve NCCN compendia and pathway requirements that are a separate post.

The exception structure above applies across all of these. The specifics of the letter change with the drug class.

If your Level 1 appeal is denied

If the plan denies the exception at Level 1, you have the right to a Level 2 review by an Independent Review Entity, fully external to the plan. I wrote a longer piece on how the IRE works at the external review request post. The same letter and documentation can go forward, often with stronger framing for the external reviewer. For the full ladder of MA appeals, see the 2026 appeals walkthrough.

The IRE overturns a meaningful share of step therapy denials when the letter is well-structured. I treat Level 1 as a procedural step. The real decision point is often the IRE.

If you want this filed for you

DenyBack is what I do when I am not writing posts like this. Flat $39, one MA denial appeal. I draft the letter, build the exception request, organize the supporting documentation, file it, and track the timeline. If it is a step therapy denial, the letter is structured the way I described above, point-by-point against each required step, and filed expedited where appropriate.

I built this because I kept watching patients lose appeals that should have been winnable, on procedural grounds, because nobody had time to structure the letter correctly.

Permission to ignore the pitch

If you have the bandwidth and a prescriber's office that moves fast, you can file this yourself. Everything in this post is something you can do without me. The regulations are public, the exception process is public, the trackers are public. The only thing I am selling is the time and the formatting discipline. If you have those, use them. If you do not, that is what DenyBack is for.

Sources:

• 42 CFR 423.578 - Exceptions process (Part D)
• 42 CFR 422.136 - MA step therapy for Part B drugs
• 84 FR 15680 - April 16, 2019 final rule
• Step Therapy Legislation by State tracker