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.

The pharmaceutical industry's focus on rare diseases has intensified, with 57% of all novel drugs approved in 2025 designated as orphan treatments. This is a continued increase from prior years, indicating a strategic shift towards smaller patient populations with high unmet needs, as exemplified by three different drugs for Hereditary Angioedema (HAE) being approved within ten weeks.

To overcome regulatory hurdles for "N-of-1" medicines, researchers are using an "umbrella clinical trial" strategy. This approach keeps core components like the delivery system constant while only varying the patient-specific guide RNA, potentially allowing the FDA to approve the platform itself, not just a single drug.

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.

Abivax's drug has a novel, not fully understood mechanism (miR-124). However, analysts believe strong clinical data across thousands of patients can trump this ambiguity for doctors and regulators, citing historical precedents like Revlimid for drugs that gained approval despite unclear biological pathways.

The Innovative Genomics Institute is tackling rare diseases by creating a standardized platform. By keeping elements like the delivery vehicle and enzyme constant and only changing the guide RNA, they aim to create a repeatable 'bucket trial' process for developing hundreds of cures, not just one-offs.

The successful use of a surrogate endpoint (proteinuria reduction) for IgA nephropathy approvals has created a clear regulatory pathway. This blueprint is now being leveraged by developers to advance therapies for other previously untreatable renal diseases like FSGS, de-risking their clinical programs.

As AI models become adept at identifying novel or experimental treatments for individuals, it will create mounting pressure on the medical regulatory system. Patients, armed with compelling, AI-generated arguments for a specific therapy, will increasingly challenge the gates kept by establishments, potentially forcing an evolution of the social contract around access to unproven medicines ('right to try').

The FDA's current leadership appears to be raising the bar for approvals based on single-arm studies. Especially in slowly progressing diseases with variable endpoints, the agency now requires an effect so dramatic it's akin to a parachute's benefit—unmistakable and not subject to interpretation against historical data.