Manufacturing

Genzyme has extensive experience in researching, developing, and manufacturing treatments for lysosomal storage disorders. Fabrazyme^® (agalsidase beta) manufacturing occurs exclusively at Genzyme production facilities. The highly complex, multistep process is established, scalable, and rigorously controlled to help ensure consistency and reliability.

Fabrazyme is produced by state-of-the-art molecular biologic techniques. Genzyme has over 10 years experience with the methodology, which is similar to that used to produce numerous other therapeutic proteins.

Early studies of enzyme replacement in the 1970s and 1980s using α-GAL purified from human tissues were promising,^[1] but practical application was impossible because of the difficulty of obtaining enough purified human enzyme. The advent of genetic engineering and recombinant human DNA technology allowed for production of substantial quantities of therapeutic proteins such as human α-GAL.

^{Well-characterized host cell to help ensure safety}

Fabrazyme production begins with genetic modification of a host cell to produce α-GAL from human DNA. The CHO (Chinese hamster ovary) cell line was chosen for its well-characterized track record in the manufacturing of biopharmaceuticals. In fact, nearly 1 million patients received therapeutic proteins produced by CHO cells during the past year ^[2]with no evidence of viral transmission. Being of non-human origin, CHO cells are less vulnerable to contamination by human viruses than cells of human origin. ^[3]

^{Protein manufactured using highly regulated techniques to help ensure reproducibility}

• The human α-GAL gene is isolated, spliced into a bacterial plasmid, and then inserted into the CHO host cell, which serves as a hospitable environment to manufacture the protein.
• In a bioreactor under carefully controlled conditions, the cells grow in a liquid medium of about 50 different nutrients such as sugar, amino acids, and salts.
• Throughout the production process the cells remain continuously in suspension, using up to 2,500 liters of medium per day.
• Liquid is removed daily and the enzyme is drawn off and collected for purification.

^{Multistep process to help ensure purity of protein}

• The enzyme goes through a multistep purification process, including chromatography and nanofiltration, capable of removing virus particles.
• To help ensure the product meets worldwide regulatory authority standards and specifications, rigorous testing takes place during every stage of the manufacturing process.

^{Product is filled, labeled, tested, and prepared for shipping}

• The purified α-GAL is stabilized with excipients and undergoes double-sterile filtration before it is distributed into vials under aseptic conditions.
• More than 20,000 vials are filled in a 6-hour period.
• The vials are lyophilized (freeze-dried to remove oxygen and water) to enhance stability and storage.
• After lyophilization, vials are ready for quality-control testing.

^{Rigorous testing to help ensure consistent quality}

• Each lot of Fabrazyme undergoes an extensive series of quality control tests before being released to confirm consistent quality.

Important Safety Information Fabrazyme (agalsidase beta) is indicated for use in patients with Fabry disease.  Fabrazyme reduces globotriaosylceramide (GL-3) deposition in capillary endothelium of the kidney and certain other cell types. The reduction of GL-3 inclusions suggests that Fabrazyme may ameliorate disease expression; however, the relationship of GL-3 inclusion reduction to specific clinical manifestations of Fabry disease has not been established. The most serious and most common adverse reactions reported with Fabrazyme are infusion reactions.  Serious and/or frequently occurring related adverse reactions consisted of one or more of the following events: chills, pyrexia, feeling hot or cold, dyspnea, nausea, flushing, headache, vomiting, paresthesia, fatigue, pruritus, pain in extremity, hypertension, chest pain, throat tightness, abdominal pain, dizziness, tachycardia, nasal congestion, diarrhea, edema peripheral, myalgia, back pain, pallor, bradycardia, urticaria, hypotension, face edema, rash, and somnolence. The occurrence of somnolence can be attributed to clinical trial specified pre-treatment with antihistamines.  Other reported serious adverse events included stroke, pain, ataxia, bradycardia, cardiac arrhythmia, cardiac arrest, decreased cardiac output, vertigo, hypoacousia, and nephrotic syndrome.  These adverse events also occur as manifestations of Fabry disease; an alteration in frequency or severity cannot be determined from the small numbers of patients studied. Infusion reactions occurred in many patients treated with Fabrazyme and some of the reactions were severe.  Patients should be given antipyretics prior to infusion.  Infusion reactions occurred in some patients after receiving pretreatment with antipyretics, antihistamines, and oral steroids.  Infusion reactions declined in frequency with continued use of Fabrazyme.  However, infusion reactions may still occur despite extended duration of Fabrazyme treatment.  Because of the potential for severe infusion reactions, appropriate medical support measures should be readily available when Fabrazyme is administered.  Patients with compromised cardiac function should be monitored closely if the decision is made to administer Fabrazyme. Most patients develop IgG antibodies to Fabrazyme.  A few patients developed IgE or skin test reactivity specific to Fabrazyme.  Physicians should consider testing for IgE in patients who experienced suspected allergic reactions and consider the risks and benefits of continued treatment in patients with anti- Fabrazyme IgE.   Patients with Fabrazyme- specific IgE antibody have been treated using a rechallenge protocol.  Rechallenge of these patients should only occur under the direct supervision of qualified personnel, with appropriate medical support measures readily available. The safety and efficacy in patients younger than 8 years of age have not been evaluated.  IgE immunologic responses in pediatric patients may differ from those in adults, as IgG seroconversion was associated with prolonged half-life concentrations of Fabrazyme, which is rarely observed in adult patients. Fabrazyme is available by prescription only. Side effects should be reported promptly to Genzyme Medical Information at 800-745-4447, option 2. To learn more, please see the full prescribing information (PDF) or contact Genzyme at 1-800-745-4447.

^References

1. Desnick RJ, Dean KJ, Grabowski G, Bishop DF, Sweely CC. Enzyme therapy in Fabry disease: differential in vivo plasma clearance and metabolic effectiveness of plasma and splenic α-galactosidase A isozymes. Proc Natl Acad Sci U S A 1979; 76:5326-30.

2. Data on file. Genzyme Corporation.

3. Wiebe ME, Becker F, Lazar R, May L, Casto B, Semense M, Fautz C, Garnick R, Miller C, Masover G, Bergmann D, Lubiniecki AS. A multifaceted approach to assure that recombinant tPA is free of adventitious virus. In: Advances in Animal Cell Biology and Technology for Bioprocesses. Great Britain, 1989; 68-71.