Adverse Reactions in Clinical Trials

Zero previously treated patients (PTPs) and previously untreated patients (PUPs) developed antibodies to the host cell proteins
Zero events of anaphylaxis or thrombosis were reported

Development of inhibitors to Factor VIII can occur following administration of Factor VIII products.

Zero inhibitors observed in clinical trials of PTPs
PUPs are at greatest risk. 12 of 24 treated subjects developed an inhibitor to Factor VIII
If expected Factor VIII levels are not attained or bleeding is not controlled with appropriate dose, perform a Bethesda inhibitor assay to measure Factor VIII inhibitor concentration

Adverse reactions

The most common adverse reactions reported in clinical trials (>0.5% of subjects) were Factor VIII inhibition in previously untreated patients (PUPs), dizziness, and hypersensitivity.

Adverse reactions reported for AFSTYLA (N=258)*

0.4%

Paresthesia

Rash

Erythema

Pruritus

Pyrexia

Injection-site pain

Chills

Feeling hot

0.8%

Dizziness

1.6%

Hypersensitivity

One patient withdrew due to an adverse reaction (hypersensitivity).

*Adverse reactions reported in adult/adolescent and pediatric studies in previously treated patients

Monitor Factor VIII activity using either the chromogenic or one-stage clotting assay

Chromogenic
assay

One-stage clotting assay

Use chromogenic assay if available to measure Factor VIII activity

Most accurately reflects the clinical hemostatic potential of AFSTYLA
Should be used if available

One-stage assay results can be used with a simple calculation

The one-stage clotting assay result underestimates the Factor VIII activity level compared to the chromogenic assay result by approximately one-half.

If the one-stage clotting assay is used, multiply the result by a conversion factor of 2 to determine the patient’s Factor VIII activity level.

One-stage assay results x 2 = Activity level

View AFSTYLA
dosing recommendations

See how AFSTYLA prevents
bleeds with prophylaxis

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Study design

Data from three AFSTYLA studies: Safety of AFSTYLA was assessed in patients enrolled in the phase I/III, open-label, multicenter, crossover study, the phase III, open-label study, and the ongoing phase III, open-label, multicenter extension study. Adverse reactions were reported for 14 of 258 (5.4%) patients in all studies. In the clinical studies, there have been a total of 28,418 exposure days, with at least 28,492 injections of AFSTYLA administered.