Table 1 Definitions and use of key concepts in major normative institutions

WHO

Defined as "Absence of cross-resistance to existing antibiotics, new chemical class, new target, or new mechanism of action."

Not defined

Not defined

EMA

Innovative medicine is defined as “A medicine that contains an active substance or combination of active substances that has not been authorised before."

Novel drugs/therapies/treatments are frequently referred to but not defined for human medicines. The focus is on whether a new antibacterial agent belongs to a new class that has a unique mechanism of action and, therefore, has the potential to address an unmet medical need. For veterinary medicines, novel therapies are defined as "therapies entirely new to veterinary medicine either, because they are genuinely novel and have not been previously used in the context of a medicine, or new only to the veterinary domain, although well-known in terms of research, and possibly in the context of human medicine."

Defined as “a condition for which there exists no satisfactory method of diagnosis, prevention, or treatment in the Union or, even if such a method exists, in relation to which the medicinal product concerned will be of major therapeutic advantage to those affected”. EMA also state that "target organisms expected to respond to treatment with the new agent and for which there are few remaining treatment options" can be considered an unmet medical need

FDA

Innovative drugs are not clearly defined but referred to as " new treatment options for patients and advances in health care for the American public."

Novel drugs/novelty is often referred to but not clearly defined. Novelty is partly addressed using the term New Molecular Entity (NME). This concept refers to an active ingredient that does not contain any active moiety previously approved under section 505 of the Federal Food, Drug, and Cosmetic Act nor previously marketed as a drug in the United States. However, FDA uses the term “novel drug” in alternative pathways designed to facilitate faster drug approval. A “novel drug approval” is considered Accelerated Approval if the drug treats a serious condition and offers a significant improvement over existing therapies. The improvement can be demonstrated by an effect on either a surrogate endpoint that is likely to predict clinical benefit or on a clinical endpoint that can be measured earlier than irreversible morbidity and mortality or is reasonably likely to predict an effect on irreversible morbidity and mortality or another clinical benefit (i.e., an intermediate clinical endpoint). Similarly, a “novel drug marketing application” receives a “Fast Track” status when the drug is intended for treating a severe or life-threatening illness or medical condition, and it shows potential for fulfilling unmet medical needs in this area. In addition, a drug may also receive Fast Track status if it is designated as a qualified infectious disease product, which is a concept under a FDA scheme to incentivize the development of antibacterial and antifungal drugs to treat serious or life-threatening infections

Defined as "a condition whose treatment or diagnosis is not addressed adequately by available therapy. An unmet medical need includes an immediate need for a defined population (i.e., to treat a serious condition with no or limited treatment) or a longer-term need for society (e.g., to address the development of resistance to antibacterial drugs).”