Unicure's experience reveals a significant regulatory risk: the FDA can reverse its position on a pre-agreed Statistical Analysis Plan (SAP). Despite prior alignment on using a natural history control, the agency later told the company this approach was merely 'exploratory,' invalidating their filing strategy and shocking investors.

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.

Voyager CEO Al Sandrock supports the FDA's use of accelerated approval for severe diseases but argues it must be coupled with industry accountability. He praises Amelix for voluntarily pulling its ALS drug after a failed confirmatory trial, framing such responsible actions as essential for maintaining the FDA's willingness to be flexible with approvals based on surrogate endpoints.

Amidst growing turmoil at the FDA, a viable strategy is to "invest around" the risk. This involves prioritizing companies whose drugs show clear data on well-understood, validated endpoints, as these are most likely to navigate the current political environment successfully, regardless of leadership changes.

Unicure's setback with its Huntington's gene therapy demonstrates a new political risk at the FDA. A prior agreement on a trial's design can be overturned by new leadership, especially if the data is not overwhelmingly definitive. This makes past regulatory alignment a less reliable indicator of future approval.

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.

After a decade on the market and multiple shifts in endpoints, Sarepta's definitive Phase 3 study for its DMD drugs failed. This outcome casts doubt on the entire accelerated approval framework for slowly progressive diseases, where surrogate endpoints may not translate to clinical benefit, leaving regulators and patients in a difficult position.

Voyager CEO Al Sandrock suggests the 30% average efficacy of new Alzheimer's drugs isn't uniform. Instead, some patients may see a complete halt in progression while others see no benefit. He argues the next critical step is predicting these responders, which will determine whether future therapies like anti-tau agents should be added on or used as a replacement.

The FDA is predicted to approve new PARP inhibitors from trials like AMPLITUDE only for BRCA-mutated patients, restricting use to where data is strongest. This contrasts with the EMA's potential for broader approvals or denials. This highlights the diverging regulatory philosophies that create different drug access landscapes in the US and Europe.