Adverse reactions
CRYSVITA was evaluated in 2 clinical studies of patients with TIO. Studies 6 and 7 were Phase 2, open-label studies in adults with TIO aged 33 to 73 years in which patients received CRYSVITA for at least 88 weeks.
| ADVERSE REACTIONS REPORTED IN CRYSVITA-TREATED ADULT PATIENTS IN STUDY 6 AND STUDY 7 | |||
|---|---|---|---|
| Adverse Reaction |
Overall (N=27) n (%) |
||
| Tooth abscessa | 5 (19) | ||
| Muscle spasms | 5 (19) | ||
| Dizziness | 4 (15) | ||
| Constipation | 4 (15) | ||
| Injection site reactionb | 4 (15) | ||
| Rashc | 4 (15) | ||
| Headache | 3 (11) | ||
| Vitamin D deficiency | 2 (7) | ||
| Hyperphosphatemia | 2 (7) | ||
| Restless legs syndrome | 2 (7) | ||
n, number of patients with an event; N, total number of patients who received at least 1 dose of CRYSVITA.
- aTooth abscess includes: tooth abscess and toothache.
- bInjection site reaction includes: injection site reaction, injection site pain, and injection site swelling.
- cRash includes: rash and rash papular.
Hypersensitivity reactions
In the Phase 2 studies, 22% of patients experienced a hypersensitivity reaction, which were mild or moderate in severity.1
Hyperphosphatemia
In the Phase 2 studies, 7% of patients experienced hyperphosphatemia, which was managed with dose reduction.1
Injection site reactions
In the Phase 2 studies, 15% of patients reported an injection site reaction (e.g., injection site reaction, injection site pain, and injection site swelling). Injection site reactions were generally mild in severity, required no treatment, and resolved in all cases.1
Restless legs syndrome
In the Phase 2 studies, 7% of patients experienced symptoms of restless legs syndrome, which were mild and did not require treatment interruption.1
No patients withdrew from the study due to adverse reactions.
There were no significant changes in frequency, type, or severity of adverse reactions reported through 144 weeks, compared with prior clinical studies in patients receiving CRYSVITA (N=162).
Immunogenicity
As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of the antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors, including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to CRYSVITA in the studies described in this website with the incidence of antibodies in other studies or to other products may be misleading.
14% of patients in Study 6 and no patients in Study 7 developed anti-drug antibodies (ADA) with no neutralizing antibody detected, and ADA did not impact drug efficacy.1
Reference
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CRYSVITA (burosumab-twza) US Prescribing Information; June 2020.