Blogging about Leapfrogging

Jan 24, 2024

To leapfrog is to improve position by means of vaulting.

In drug development it is vaunted to be vaulted into special position via FDA expedited approval programs. The 5 programs whose labels confer special status on the companies that receive them are:

  1. Priority Review, which speeds up FDA review from approximately 10 months (300 days) to 6 months (180 days). Criteria to receive it are drugs “with significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of serious conditions when compared to standard applications.” The European Union also called the European Medicines Agency (EMA) counterpart is Accelerated Assessment.
  2. Fast Track, which involves early communication with the FDA and review of applications in portions for drugs with the potential to address serious conditions, and unmet medical needs. The FDA can rescind Fast Track designation if a drug no longer meets designation requirements. The European Union counterpart is called priority medicines or PRIME.
  3. Breakthrough Therapy, which provides all the benefits of Fast Track designation plus even more intensive guidance on how to efficiently develop a drug. Criteria to receive it are drugs that treat serious diseases for which preliminary clinical evidence suggests substantial evidence over existing therapies on one or more clinical endpoints. The European Union counterpart is called priority medicines or PRIME.
  4. Accelerated Approval, which involves FDA approval based on surrogate or intermediate endpoints that are likely to predict clinical benefit and meet an unmet need for a serious condition. FDA defines a “surrogate endpoint” as “a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure, that is thought to predict clinical benefit, but is not itself a measure of clinical benefit.” The European Union counterpart is Conditional Marketing Authorisation.
  5. Priority Review Vouchers (PRVs), which are awarded based on the development of drugs for tropical diseases or rare pediatric diseases or for use as medical countermeasures. The PRV is sellable to another company, or redeemable later to receive priority review from the FDA with a targeted review time of 6 months, rather than the 10-month standard review, for a drug application of the PRV holder’s choice. There is no European equivalent.

An FDA table is shown below:

The small molecule, RRx-001, has already received Fast Track designation for its activity as an anti-oral mucositis agent in first line head and neck cancer. It is potentially eligible for a Priority Review Voucher given its development as a radiation countermeasure in the event of a potential public health emergency from a terrorist attack with a biological, chemical, or radiological/nuclear material, or a naturally occurring emerging disease.

For AdAPT-001 based on several complete responses in the ongoing Phase 2 trial one or more of these priority designations are potentially on the table.

Or should we say, “in the hopper?”