Primary Risk Drivers
Below is a snapshot of domains that materially influence the MARA Rating.
Clinical effectiveness
Fitusiran demonstrates a clear clinical advantage with significant reductions in annualized bleeding rates (ABR) compared to standard on-demand therapies in phase 3 trials. The ATLAS-INH and ATLAS-A/B trials reported a 90.8% and 90% reduction in ABR, respectively, with p-values indicating strong statistical significance. However, the approved dosing regimen’s efficacy is based on indirect comparisons due to the non-approval of the original fixed-dose regimen, which slightly limits the robustness of the evidence.
Cost effectiveness
No formal cost-effectiveness analyses or ICER values were identified in the accessible sources. The absence of QALY estimates and detailed economic models prevents a robust evaluation of cost-effectiveness. While some cost-savings analyses were available, they do not provide sufficient evidence to support a cost-effective designation.
Quality of life
The evidence indicates moderate improvements in HRQoL, particularly through the use of hemophilia-specific instruments like Haem-A-QoL. Although some changes were reported as clinically meaningful, the lack of numeric EQ-5D values limits the overall assessment of utility. The data suggest positive trends in HRQoL, especially in the context of reduced treatment burden due to less frequent dosing.
Supporting Domains
Safety and Adverse Effects
Fitusiran has an acceptable safety profile with manageable adverse events. Serious adverse reactions were reported at a low rate (1.4%), and while there are boxed warnings for thrombotic events and gallbladder disease, the overall incidence of serious adverse events appears low, particularly under the approved dosing regimen.
Comparator Selection
The pivotal trials used on-demand therapies as comparators, which may not fully reflect the current standard of care for severe hemophilia. While the evidence includes comparisons to prior prophylaxis in switching studies, the lack of head-to-head trials against newer agents like emicizumab limits the robustness of the comparator selection.
Patient Population and Subgroups
The trials enrolled a representative population of males aged 12 years and older with hemophilia A or B, including those with and without inhibitors. Subgroup analyses were conducted, although there is limited visibility into other relevant subgroups. Overall, the population appears adequately represented for the intended use.
Care Pathway Integration
Fitusiran can be integrated into existing care pathways with minor adjustments. The requirement for AT activity monitoring and training for administration is manageable within current clinical practices. The subcutaneous administration route is also compatible with existing treatment protocols.
Resource Use and Cost Implications
While the WAC for fitusiran is disclosed, the overall resource implications remain unclear due to the lack of detailed cost data and the potential for high implementation costs associated with monitoring requirements. The evidence suggests a significant cost burden, but the exact implications are not fully quantified.
Evidence Quality and Robustness
The evidence base is supported by multiple phase 3 trials, although the reliance on open-label designs and indirect comparisons for the approved regimen introduces some bias. Overall, the quality of evidence is strong, with consistent findings across studies.
Uncertainty, Sensitivity, and Broader Impacts
There is moderate uncertainty regarding the long-term effectiveness and safety of fitusiran, particularly due to the lack of real-world evidence and the reliance on trial data. The economic implications also introduce uncertainty, as detailed cost-effectiveness analyses are not available.
