Methods for sterilizing preparations of monoclonal immunoglobulins

Abstract

Methods are disclosed for sterilizing preparation of monoclonal immunoglobulins to reduce the level of active biological contaminants such as viruses, bacteria, yeasts, molds, mycoplasmas, prions and parasites.

Description

FIELD OF THE INVENTION [0001] The present invention relates to methods for sterilizing preparations of monoclonal immunoglobulins to reduce the level of active biological contaminants therein, such as viruses, bacteria, yeasts, molds, mycoplasmas, prions and / or parasites. BACKGROUND OF THE INVENTION [0002] Antibodies are produced by organisms in response to exposure to foreign substances that the body perceives as a threat. Antibodies, or as they are collectively known, immunoglobulins (Ig), are proteins secreted by cells of the immune system known as B-cells or plasma cells. The structure of immunoglobulins is complex, but is well characterized. In brief, each immunoglobulin consists of a complex of protein chains known as the heavy and light chains. Each heavy chain is linked to a single light chain via disulfide bonds. The resulting complex is in turn linked by additional disulfide bonds to an identical heavy-light chain complex. This basic unit can be assembled by the cell into ...

AI Technical Summary

Benefits of technology

[0020] In accordance with these and other objects, a first embodiment of the present invention is directed to a method for sterilizing a preparation of monoclonal immunoglobulins that is sensitive to radiation comprising: (i) reducing the residual solvent content of a preparation of monoclonal immunoglobulins to a level effective to protect the preparation of monoclonal immunoglobulins from radiation; and (ii) irradiating the preparation of monoclonal immunoglobulins with radiation at an effective rate for a time effective to sterilize the preparation of monoclonal immunoglobulins.

[0022] A third embodiment of the present invention is directed to a method for sterilizing a preparation of monoclonal immunoglobulins that is sensitive to radiation comprising: (i) reducing the residual solvent content of a preparation of monoclonal immunoglobulins to a level effective to protect the preparation of monoclonal immunoglobulins from radiation; (ii) adding to the preparation of monoclonal immunoglobulins at least one stabilizer in an amount effective to protect the preparation of monoclonal immunoglobulins from radiation; and (iii) irradiating the preparation of monoclonal immunoglobulins with radiation at an effective rate for a time effective to sterilize the preparation of monoclonal immunoglobulins. According to this embodiment, steps (i) and (ii) may be reversed.

Problems solved by technology

In this way, the extremely large number of potential immunoglobulin molecules that might be manufactured is limited to only those molecules that recognize antigens to which the body must respond.

In contrast, when an extreme degree of specificity is required, or when a single defined therapeutic goal is sought, polyclonal immunoglobulins are not the best solution.

Each of these methods may result in contamination of the product by pathogens.

Contamination of the culture system by bacteria, yeast or mold may also occur.

Obviously, these products face the risk of contamination by pathogens infecting or harboured by the host animal.

Such procedures, however, are not always reliable and are not able to detect the presence of viruses in very low numbers.

This reduces the value or certainty of the test in view of the consequences associated with a false negative result.

False negative results can be life threatening in certain cases, for example in the case of Acquired Immune Deficiency Syndrome (AIDS).

Furthermore, in some instances it can take weeks, if not months, to determine whether or not the product is contaminated.

This is a result of safety concerns for the workers conducting the tests, and the difficulty and expense associated with the containment facilities and waste disposal.

Heat treatment requires that the product be heated to approximately 60° C. for about 70 hours which can be damaging to sensitive products.

Heat inactivation can destroy 50% or more of the biological activity of the product.

Unfortunately this method may also remove products that have a high molecular weight.

Further, in certain cases small viruses may not be removed by the filter because of the larger molecular structure of the product.

This procedure requires that unbound sensitizer is washed from products since the sensitizers are toxic, if not mutagenic or carcinogenic, and can not be administered to a patient.

The published literature in this area, however, teaches that gamma radiation can be damaging to radiation sensitive products, such as blood, blood products, protein and protein-containing products.

In particular, it has been shown that high radiation doses are injurious to red cells, platelets and granulocytes (Leitman).

Unfortunately, many sensitive biologicals, such as monoclonal antibodies (Mab), would lose viability and activity if subjected to freezing for irradiation purposes and then thawing prior to administration to a patient.

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