Denileukin diftitox
As of the edition of 20 October 2026, Denileukin diftitox is a protein: marketed, first approved in 1999 (US); acts on EEF2, IL2RA and IL2RB; US protection ended in 2011.
Sources: FDA Orange Book and Purple Book, other approval registers, ClinicalTrials.gov, ChEMBL.
The drug
- Status
- Marketed; latest approval 2021
- Kind
- Protein
- Brand name
- Ontak
- First approved
- 5 February 1999 (US)
- Approvals on record
- 3 in 2 regions
- Holder of the most recent approval
- Citius Oncology; 2 holders in all
- Registered trials
- 42, 10 stopped early
- Disease areas
- Cancer; Blood and lymph; Immune system; Skin and connective tissue; Hormones; Pregnancy and women's health
US protection
US protection ended in 2011.
US protection ended in 2011, computed as 12 years from the first US licence because FDA publishes no date for this product. The application that gives this date is held by Eisai. The date is computed, not published.
This is the US only, and it is not the date generics or biosimilars can enter.
The exact date and the listings behind it
In the product2 listings count towards this date. The exact date and each listing are in the product.
See the exact date and the 2 listings behind itRequest access. Nothing is shown until you do.
Targets
Registered trials
| Phase | Trials | Completed | Active | Stopped early |
|---|---|---|---|---|
| Phase not stated | 3 | 1 | 0 | 1 |
| Phase 1 | 7 | 5 | 0 | 2 |
| Phase 2 | 28 | 18 | 1 | 7 |
| Phase 3 | 1 | 1 | 0 | 0 |
| Phase 4 | 3 | 3 | 0 | 0 |
| All trials | 42 |
Who has held its approvals
| Company | Role | Years |
|---|---|---|
| Eisai | Applicant and Lead sponsor of trials | 1999 to now |
| Citius Pharmaceuticals | Later holder | 2024 to now |
| Citius Oncology | Acquired holder | 2026 to now |