The anti-amyloid rollout is rate-limited by infrastructure, not science

The conversation around anti-amyloid antibodies has shifted in a way that is easy to miss if you are reading only the trial readouts. The clinical question — do these drugs slow decline in early Alzheimer's — has been answered, with the qualifications the data warrant. The regulatory question has been answered. The CMS coverage question, after the coverage-with-evidence-development decision, has been answered.

What has not been resolved is whether the delivery system can actually scale to meet the eligible population.

The bottleneck is operational

Three constraints define the current rollout shape:

• Infusion-chair capacity. Biweekly IV administration consumes scheduling slots that compete with oncology infusions and other long-running biologic regimens. In practice, anti-amyloid infusions tend to lose that competition.
• MRI surveillance throughput. ARIA monitoring requires baseline and on-treatment MRIs at protocol-defined intervals, draining scanner time that already runs at high utilization in most health systems.
• Specialist availability. Cognitive neurologists and dementia specialists qualified to confirm eligibility, manage ARIA, and conduct the requisite counselling are concentrated in academic centers. Community practice access is patchy.

Each of these constraints has its own time horizon. Infusion capacity is partly addressable through subcutaneous formulations, which are advancing toward approval. MRI throughput is much harder to expand on a meaningful timeline. Specialist supply is the longest-cycle constraint of all.

What this means for the next twelve months

The eligible patient pool — early Alzheimer's, amyloid-positive, MRI-clearable, APOE genotype-considered — is large. The treated patient pool is much smaller. The gap is not a science gap or a payment gap. It is a logistics gap, and it will close on the timeline that physical infrastructure changes, which is years not quarters.

For sponsors, that suggests that subcutaneous formulations are not a marginal product improvement; they are the most consequential near-term lever on uptake. For health systems, the decision to invest now in MRI capacity, infusion scheduling, and trained dementia care teams will determine market share three years out. For patients and families, the practical reality is that geographic and institutional luck still play an outsized role in whether disease-modifying therapy is actually accessible.

What we are watching

The leading indicators worth tracking are subcutaneous filing decisions, MRI capacity expansion announcements at large health systems, and the published registry data CMS will eventually use to refine coverage. None of these will move dramatically in any single quarter. All of them, taken together, will determine the shape of the rollout through 2028.

This is the unglamorous truth of disease-modifying therapy in Alzheimer's at this moment: the science has done its part, and now the operational layer has to catch up.