# First-in-class medication

A first-in-class medication is a prototype drug that uses a "new and unique mechanism of action" to treat a particular medical condition. While the Food and Drug Administration's Center for Drug Evaluation and Research tracks first-in-class medications and reports on them annually, first-in-class is not considered a regulatory category. Although many first-in-class medications qualify as breakthrough therapies, Regenerative Medicine Advanced Therapies and/or orphan drugs, first-in-class status itself has no regulatory effect.

## Examples

| Drug | Class | Targeted conditions | Year approved (FDA) | Year approved (EMA) |
| Inotuzumab ozogamicin (Besponsa) | Anti-CD22 monoclonal antibody-drug conjugate | Relapsed or refractory B cell precursor acute lymphoblastic leukemia | 2017 | |
| Tagraxofusp (Elzonris) | Interleukin 3-diphtheria toxin fusion protein targeting plasmacytoid dendritic cells | Blastic plasmacytoid dendritic cell neoplasm | 2018 | 2021 |
| Midostaurin (Rydapt) | Multi-target tyrosine kinase inhibitor not inhibited by the D816V cKit mutation | Systemic mastocytosis, myelodysplastic syndrome, acute myeloid leukemia | 2017 | 2017 |
| Teprotumumab (Tepezza) | Anti-IGF-1R monoclonal antibody | Graves' ophthalmopathy | 2020 | |
| Romosozumab (Evenity) | Anti-sclerostin monoclonal antibody | Osteoporosis | 2019 | 2019 |
| Ocrelizumab (Ocrevus) | Anti-CD20 monoclonal antibody | Multiple sclerosis | 2017 | 2018 |
| Ivosidenib (Tibsovo) | Small molecule inhibitor of isocitrate dehydrogenase 1 | Acute myeloid leukemia, cholangiocarcinoma | 2018 | 2023 |
| Bempedoic acid (Nexletol) | Adenosine triphosphate-citrate lyase inhibitor | Hypercholesterolemia | 2020 | 2020 |
| Tafamidis (Vyndaqel, Vyndamax) | Transthyretin chaperone (stabilizer) | Familial amyloid polyneuropathy and other transthyretin amyloidoses | 2011 | 2019 |
| Voxelotor (Oxbryta) | Hemoglobin oxygen affinity modulator | Sickle cell disease | 2019 | |
| Lonafarnib (Zokinvy) | Farnesyltransferase inhibitor | Hutchinson-Gilford progeria syndrome | 2020 | 2022 |
| Dupilumab (Dupixent) | Interleukin-4 receptor alpha subunit inhibitor | Asthma, atopic dermatitis, allergic diseases | 2017 | |
| Lasmiditan (Reyvow) | Selective 5-HT$_{1F}$ serotonin receptor agonist | Migraine | 2019 | 2022 |
| Tazemetostat (Tazverik) | Selective EZH2 inhibitor | Epithelioid sarcoma | 2020 | |
| Tirzepatide (Mounjaro) | GLP-1 and GIP activator | adult type 2 diabetes | 2022 | 2022 |

## Controversy
### Safety

By definition, a first-in-class drug does not have the safety evidence from analogous products that not-first-in-class drugs would have. However, a study investigating recalls and warnings in relation to first-in-class drugs approved between 1997 and 2012 by Health Canada has found that first-in-class drugs actually have a more favourable benefit-to-harm ratio.

### Economics

First-in-class drugs are often seen as commercially more attractive as they may tap into a market segment that has hitherto been underserved, but this may be illusory. In fact, most blockbuster drugs (drugs with annual sales revenues exceeding US$1,000,000,000) were not first-in-class drugs. The economic potential of a first-in-class drug, which is typically priced higher than later drugs in the same class, has been largely declining due to efforts by health insurers to restrict what specialty drugs are covered and prevent incumbency advantages.

### Costs

A lower number of available therapeutic options correlates with higher prices. In addition, many first-in-class medications are specialty drugs and orphan drugs, which means that manufacturers have to recoup development costs from a smaller market. This raises ethical questions about the sustainability of the high prices on these costs.