Chemo Research S.L.U. – FDA CRL

The U.S. Food and Drug Administration (FDA) issued a Complete Response Letter (CRL) to Chemo Research, S.L., c/o Exeltis USA, Inc., on May 29, 2025, for New Drug Application (NDA) 219029 concerning dienogest and ethinyl estradiol tablets. The FDA determined the application could not be approved due to an unacceptable benefit/risk profile.

The main issue identified was a markedly increased risk of venous thromboembolism (VTE) associated with the proposed dienogest and ethinyl estradiol combination. This conclusion was drawn from a review of the safety database from Study LPRI-424/303 and further substantiated by higher VTE rates in European postmarketing data for the same drug combination, compared to other combination oral contraceptives (COCs). The FDA concluded that this elevated VTE risk renders the product's benefit/risk profile unacceptable for its intended use in preventing pregnancy.

Under the regulatory framework of the NDA process, specifically referencing 21 CFR 314.110, Chemo Research, S.L. is required to take an action within one year from the letter's date. The FDA explicitly stated it cannot recommend further actions for the approval of this specific application but indicated it would consider a new original NDA for a different COC product if it presented a more favorable benefit/risk profile. The proposed product cannot be legally marketed.