The ultimate goal of precision medicine is a unique drug for each patient. However, this N-of-1 model directly conflicts with the current economic and regulatory system, which incentivizes developing drugs for large populations to recoup massive R&D and approval costs.

While AI enables rapid drug creation for single individuals (n-of-1), the economic model is broken. It is not a commercial opportunity, creating an urgent societal challenge to develop new funding mechanisms like public-private partnerships to support these life-saving, non-scalable treatments.

The FDA's new pathway for rare disease drugs, based on causal biology, is scientifically promising. However, the name "plausible mechanism" is a critical flaw. The term sounds weak, creating doubt for patients and giving payers powerful leverage to deny coverage by implying a lower standard of evidence.

The FDA publicly champions rare disease drug development, but its actions—frequent and inconsistent rejections—tell a different story. This disconnect between rhetoric and reality creates significant uncertainty, causing prominent investors like Rod Wong of RTW Investors to reduce their investments in the space.

The standard approach to reducing cancer drug toxicity is narrowing the target to specific mutations (e.g., HER2, KRAS). While this improves safety, it drastically shrinks the addressable patient population for each new therapy. This puts immense pressure on the pharmaceutical business model, where development costs average $2.5 billion per drug.

Contrary to their name, rare diseases are not a niche issue. Citing a 2019 study, Rabinowitz reframes them as a massive socioeconomic burden, costing the U.S. a trillion dollars annually. This is split between $500 billion in direct medical expenses and $500 billion in lost productivity for families navigating long diagnostic odysseys.

The Orphan Drug Act successfully incentivized R&D for rare diseases. A similar policy framework is needed for common, age-related diseases. Despite their massive potential markets, these indications suffer from extremely high failure rates and costs. A new incentive structure could de-risk development and align commercial goals with the enormous societal need for longevity.

The fastest, cheapest path to drug approval involves showing a small survival benefit in terminally ill patients. This economic reality disincentivizes the longer, more complex trials required for early-stage treatments that could offer a cure.

Previously considered a capital-efficient area due to regulatory flexibility, the rare disease and gene therapy space is now perceived as high-risk. The FDA is applying greater scrutiny and tightening standards, making development more unpredictable for sponsors.