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505(b)(2): Repositioning, Repurposing or What?

Some define repositioning as the process of examining alternate indications for drugs that have failed in the clinic. Others say that repurposing (with or without the hyphen; re-purposing) is interchangeable with repositioning. When many people think of repositioning drugs, they expect the outcome to be new IP and a full NDA. Pharma does repositioning as a way to salvage a drug that was in its pipeline. But repositioning in pharma can also be used to extend the life of an approved drug.

Premier Consulting specializes in helping its clients make changes to drug products that are already on the market. Since there is often publicly available nonclinical and clinical information to support the existing product and the proposed changes, Premier Consulting uses the 505(b)(2) regulatory pathway to gain approval. The changes we make are also very much applicable to pharma “repositioning.”

It is well established that the efficacy of many existing drugs are less than optimal. In fact, new drugs often fail in Phase 3 because they don’t show superiority to placebo. The following figure shows that, for many classes of drugs, less than 50% of patients find them effective.


Why aren’t a greater percentage of currently marketed more effective? While there are many reasons, sometimes it is the dose, site of administration, or formulation. Many of these drugs can be improved – “repositioned” – by making the required changes.

For many drugs, lack of efficacy may also be related to the time of dose. To address the timing of a dose, it may be possible to design an appropriate formulation.

Take prodrugs as an example. Prodrugs are modifications of new or existing drugs to improve efficacy or safety. Prodrugs can be developed to improve bioavailability, to change an IV to oral administration. Oral delivery may reduce side effects and allow higher doses.

In summary, drug repositioning or repurposing can be performed on both pipeline and currently marketed drugs. 505(b)(2) can be used to gain approval of the repositioned or repurposed marketed drugs.