Originally published by our sister publication Specialty Pharmacy Continuum

By SPC Staff

The FDA approved fitusiran (Qfitlia, Sanofi) for adults and children 12 years of age and older with hemophilia A or B, with or without factor VIII or IX inhibitors. The medication is indicated for routine use to prevent or reduce the frequency of bleeding episodes and administered subcutaneously starting once every two months. 

Fitusiran reduces the amount of antithrombin to help increase thrombin production. Its approval was based on two multicenter, randomized clinical trials with 177 adult and pediatric male participants in total. The first trial included patients with inhibitory antibodies to factor VIII or IX who previously received on-demand treatment with bypassing agents for bleeding (ClinicalTrials.gov Identifier: NCT03417102), while patients in the second trial did not have the inhibitory antibodies and had previously received on-demand treatment with clotting factor concentrates (NCT03417245).

In both trials, participants received either a monthly dose of fitusiran or their typical treatment for nine months. The fixed dose used in the trial led to excessive clotting in some patients. However, in a long-term extension study the participants received an adjustable dose based on periodic measurements of antithrombin activity, which is the dosage regimen the FDA approved. The researchers compared patients using this dosing regimen during the extension study with the control groups from the two randomized trials.

Participants with and without inhibitors, respectively, who received the antithrombin-based dosing regimen of fitusiran experienced a 73% and 71% reduction in estimated annualized bleeding rate (ABR) compared with those who received their typical treatment (estimated mean ABR, 5.1 vs. 19.1; P=0.0006 and 9.0 vs. 31.4; P<0.0001). 

“Today’s approval of Qfitlia is significant for patients with hemophilia because it can be administered less frequently than other existing options,” stated Tanya Wroblewski, MD, the deputy director of the Division of Non-Malignant Hematology in the FDA’s Center for Drug Evaluation and Research. “This new treatment option highlights our continued efforts to improve the lives of patients with hemophilia.”

Alongside the new drug, Sanofi launched a patient support program called HemAssist to provide resources for insurance, financial assistance and education. “Qfitlia can offer the fewest doses of all prophylactic therapies, and it will have a comparable price to other prophylactic hemophilia treatments,” the company wrote.

Fitusiran has a boxed warning for thrombotic events as well as acute and recurrent gallbladder disease, with some patients requiring gallbladder removal. The drug also has a warning about hepatotoxicity and the need to monitor liver tests at baseline and then monthly for at least six months after treatment initiation or a dose increase. The most common side effects (incidence >10%) are viral infection, nasopharyngitis and bacterial infection.

The prescribing information for fitusiran can be found here.

Based on FDA and company press materials.