Molecular and Chemical Structure of VPRIV
VPRIV is derived from a human cell line and designed to have an amino acid sequence identical to the naturally occurring human enzyme.1
- VPRIV is composed of 497 amino acids, with a sequence identical to the natural human enzyme glucocerebrosidase1
- The glycan structure of VPRIV contains predominantly high-mannose type glycans, consisting of 6 to 9 mannose units with a predominant 9-mannose structure2
- Data are from an in vitro study evaluating the molecular structure and cellular internalization of the human cell line-produced VPRIV2
- In vitro test results do not necessarily correlate with clinical efficacy
Adapted from Brumshtein B et al, Oxford University Press, copyright 2010.2
VPRIV® (velaglucerase alfa) for injection is indicated for long-term enzyme replacement therapy (ERT) for patients with type 1 Gaucher disease.
Important Safety Information
Hypersensitivity reactions, including anaphylaxis, have occurred. The most serious adverse reactions in patients treated with VPRIV (velaglucerase alfa) for injection were hypersensitivity reactions.
Hypersensitivity reactions were the most commonly observed adverse reactions in patients treated with VPRIV in clinical studies. Patients were not routinely pre-medicated prior to infusion of VPRIV. The most commonly observed symptoms of hypersensitivity reactions were: headache, dizziness, hypotension, hypertension, nausea, fatigue/asthenia, and pyrexia. Hypersensitivity reactions in the clinical trials include any event considered related to and occurring within up to 24 hours of VPRIV infusion, including one case of anaphylaxis. Generally the reactions were mild and, in treatment-naïve patients, onset occurred mostly during the first 6 months of treatment and tended to occur less frequently with time. Additional hypersensitivity reactions of chest discomfort, dyspnea, pruritus and vomiting have been reported in post-marketing experience. In some cases vomiting can be serious, requiring hospitalization and/or drug discontinuation.
As with any intravenous protein product, hypersensitivity reactions are possible, therefore, appropriate medical support, including personnel adequately trained in cardiopulmonary resuscitative measures and access to emergency measures, should be readily available when VPRIV is administered. If anaphylactic or other acute reactions occur, immediately discontinue the infusion of VPRIV and initiate the appropriate medical treatment.
Management of hypersensitivity reactions should be based on severity of the reaction, such as slowing the infusion rate, treatment with medications such as antihistamines, antipyretics and/or corticosteroids, and/or stopping and resuming treatment with increased infusion time. In cases where patients have exhibited symptoms of hypersensitivity to velaglucerase alfa or excipients in the drug product or to other enzyme replacement therapy, pre-treatment with antihistamines and/or corticosteroids may prevent subsequent reactions.
The most common adverse reactions during clinical studies (in ≥10% of patients) were hypersensitivity reactions, headache, dizziness, abdominal pain, nausea, back pain, joint pain, prolonged activated partial thromboplastin time (aPTT), fatigue/asthenia, and pyrexia. In clinical studies, the overall frequency of adverse events was generally higher in the population naïve to enzyme replacement therapy (ERT) than in the population switched from imiglucerase to VPRIV.
The safety and efficacy profiles were similar in pediatric (ages 4 to 17) and adult patients. The safety of VPRIV has not been established in patients under 4 years of age. Adverse reactions more commonly seen in pediatric patients compared to adult patients include (>10% difference): rash, aPTT prolonged, and pyrexia.
The adverse reaction profile in elderly patients was consistent with that previously observed across pediatric and adult patients. In general, dose selection for an elderly patient should be approached cautiously, considering comorbid conditions. As with all therapeutic proteins, there is a potential for immunogenicity. In clinical studies, 1 of 54 (2%) enzyme treatment-naïve patients treated with VPRIV developed IgG class antibodies (neutralizing in an in vitro assay). One additional patient developed IgG antibodies to VPRIV during an extension study. It is unknown if the presence of IgG antibodies to VPRIV is associated with a higher risk of infusion reactions. Patients with an immune response to other ERTs who are switching to VPRIV should continue to be monitored for antibodies to VPRIV.
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