What prior authorization or step therapy rules restrict access to new Alzheimer’s therapies?
Executive summary
Medicare rules and clinical-guideline driven diagnostic requirements are the main barriers reported that restrict access to new Alzheimer’s disease (AD) therapies: CMS has declined to broadly cover amyloid‑targeting monoclonal antibodies under standard Medicare benefits, and expert guidance narrows who should be tested and treated to people with cognitive impairment confirmed by biomarkers (e.g., amyloid/tau) rather than asymptomatic carriers [1] [2]. Research and advocacy sources call for insurance coverage of diagnostic tests and for policy changes; available sources do not mention other specific prior‑authorization protocols used by commercial plans [3] [1].
1. CMS policy is the gating policy that matters most for many patients
The Alzheimer’s Association reports that the Centers for Medicare & Medicaid Services (CMS) excludes monoclonal antibodies directed at amyloid from routine Medicare coverage, a decision the association says “continues to block” access to FDA‑approved treatments and that CMS refuses to change despite new evidence [1]. That CMS stance functions as a de facto access rule for millions of older Americans because Medicare is the dominant payer for people with AD [1]. The Alzheimer’s Association frames the CMS policy as a governmental barrier that places an administrator between patients and clinicians deciding appropriate FDA‑approved therapies [1].
2. Diagnostic and eligibility guidance narrows who is eligible
Clinical practice guidance recommends limiting diagnostic testing and treatment eligibility to people with cognitive impairment, not to asymptomatic individuals who merely carry risk genes such as APOE4 [2]. The Alzheimer’s Association’s updated practice guideline explicitly advises against using these tests in people without cognitive symptoms, and it emphasizes determining eligibility for disease‑modifying therapies through structured evaluation [2]. That narrows the patient pool who can meet payers’ or clinicians’ criteria for new therapies [2].
3. Biomarker‑driven pathways create implicit step‑therapy
The new generation of disease‑modifying therapies was developed and approved based on biomarker‑defined populations; the literature emphasizes amyloid and tau biomarkers and early‑stage intervention [4] [5]. Because trials and guidelines center on biomarker confirmation, payers and clinicians are likely to require biomarker evidence (PET, CSF, or validated blood tests) before authorizing therapy—creating an implicit step: diagnosis by biomarker, then treatment [4] [5]. Research and advocacy groups are urging insurers to cover diagnostic tests to avoid this diagnostic step becoming an access bottleneck [3].
4. Diagnostic testing access is the bottleneck many groups highlight
Advocates and federal reports push for insurance coverage of diagnostic tests to “speed up diagnosis and provide faster access to treatments” that can slow progression [3]. New blood tests approved in 2025 that can support diagnosis promise to lower barriers, but access depends on payer policies and whether insurers will pick up testing costs—something sources say is under policy debate [6] [3]. NIH and federal programs are funding tools for primary care diagnosis to reduce barriers, recognizing that testing requirements can restrict uptake [7].
5. Clinical and payer landscapes are changing but divergent
Medical reviews and pipeline analyses describe a rapidly evolving treatment landscape with multiple FDA‑approved anti‑amyloid antibodies and many drugs under study; clinical recommendations emphasize early‑stage intervention and biomarker use [4] [8]. Yet policy decisions—most notably CMS’s coverage stance—have not mirrored clinical momentum, creating a split between scientific guidance and payer practice [1] [8]. That divergence produces uncertainty for patients, clinicians and industry about who will get prompt access.
6. What reporting does not say (important limitations)
Available sources do not provide detailed, plan‑by‑plan prior‑authorization forms, step‑therapy rules used by individual commercial insurers, or exact criteria (e.g., required test thresholds, review timelines) used in practice; those specifics are not reported in the supplied materials (not found in current reporting). Similarly, the sources do not document post‑2025 commercial‑plan changes or the full impact of newly approved blood tests on insurer behavior (not found in current reporting).
7. Bottom line for patients and policymakers
The chief restrictions are policy and diagnostic gating: Medicare’s noncoverage for amyloid‑targeting monoclonals and guideline emphasis on biomarker‑confirmed cognitive impairment limit access [1] [2]. Advocacy groups call for insurance mandates to cover tests and treatments to align payer rules with evolving science [3]. Those who want to track or challenge access barriers should focus on CMS policy change, insurer test‑coverage decisions, and adoption of biomarker testing in primary care—areas explicitly discussed in the available sources [1] [3] [7].