Key Takeaways from Roundtable on ALN-6400 (Plasminogen)

Research evidence excerpt

Key Takeaways from Roundtable on ALN-6400 (Plasminogen)

UpdateMpeople in the US and ~1.4M worldwide, though only ~35% are estimated to be

diagnosed ( Exhibit 4 ), which Alnylam expects would improve with a new therapy

on the market. The disease is characterized by abnormal blood vessels connecting

arteries to veins ( Exhibit 5 ), which are often fragile and lead to rupture and

bleeding. The most common symptom is frequent and severe epistaxis (nose

bleeds), while many patients experience GI or mucosal bleeding as well. Of note,

68% of HHT patients are anemic or iron deficient, 11% are hospitalized due to HHT

each year, and patients have thrombotic risk 2-4x the general population. A KOL on

the call highlighted that even nose bleeds can meaningfully impair quality of life and

can even be life threatening as they can occur spontaneously, are severe, and can

have a long duration, sometimes requiring systemic medical/surgical intervention or

iron/RBC transfusions to manage. Beyond transfusions, standard of care consists of

off-label use of antifibrinolytic therapy in mild/moderate patients ( Exhibit 6 ), which

has shown modest efficacy, is associated with increased thrombotic risk, and

requires multiple doses daily. For more severe patients systemic antiangiogenic

therapy, often prescribed to cancer patients, are used off-label and have their own

array of side effects. Accordingly, the unmet need in HHT remains high and the KOL

highlighted durable protection for epistaxis and mucocutaneous bleeding, low/no

thrombotic risk, and low treatment burden (reduce RBC/iron transfusions) as key

elements he would look for in a next-gen therapy.

VWD represents an undertreated disease with limited therapeutic options. VWD