In Figure 6, we see that regulations covering the use of monoclonal antibodies are the same in both cases; its demanding features
are the same. We also took into account the regulations as have been previously noted.
Figure 6. Comparison of Regulations for Monoclonal Antibodies
However, when analyzing the higher cost of each assay made in the process of a monoclonal antibody and following all the rest
of the required analyses, we arrive at the conclusion that it is quite high. We could ask: "Why it is necessary to maintain
the same regulations for MAb use as a reagent to purify biologicals?" The recommendations for characterization and testing
of MAbs used as parenterals are, of necessity, very stringent. Not all of them would be applicable to MAbs that are used as
reagents in drug manufacturing.
To provide an adequate description of the manufacturing technology used in the production of the MAb, to ensure satisfactory
performance of the reagent during the process, and to assess its potential impact on the biological safety, quality, and purity,
the production of MAbs includes the following phases:
1. Development and characteri-zation of the cell line
2 Establishment of the cell banks
3. Production in animals (ascites fluid)
4. MAb purification
5. MAb linked to Sepharose CL-4B
The basic elements of compliance include: written SOPs, flowcharts, the immunoaffinity matrix, and Quality Control (QC) and
Process Control (PC) specifications. The written SOPs describe each operation. See Figure 4 where some of the SOPs used in
our process, including, approval authority, change control, history files, and standard formats, are listed.13 The flowchart for the production of anti-HBsAg monoclonal antibody and the immunoaffinity matrix is shown in Figure 1. Here,
the QC and the PC stand for controls that are carried out in every step.
Although experts expound that in the future all the MAbs can be delivered and certificated according to existing regulations,
we consider that the regulations for the monoclonal antibodies used as reagents could resemble the following:
Cell Line Characterization and Development
This information is important because it will determine, in part, what adventitious agents tests should be performed in those
cases where extensive testing may be necessary. (The suppliers certify the fetal bovine serum as free of bovine viruses, Bovine
Spongiform Encephalopathy (BSE), and mycoplasmas.)
- Other characterization, such as subclass and molecular weight determination, should be performed early so that appropriate
identity tests can be developed for production lots.
- Major concerns in cell bank establishment in-clude verification of the identity and clonality of the banked cells and acceptable
degrees of freedom from adven-titious agents.
In our case, CB.Hep-1 MCB is free from adventitious agents and the MAb characterization corresponds to the MAb secreted by
the original cell line; therefore, it can be used in the rHBsAg purification process. Aleman, et al. 2000, publishes these
Production in Animals (Ascites fluid)
In general, steps should be taken to prevent or control contamination (e.g., virus, bacteria, fungi, myco-plasma) introduced
during the production process. Recommended characterization of the MAb production process, again, will depend on the subsequent
downstream processing of the drug substance.
Isolation and Purification
For reagents, the predominant concern is whether the MAb purity is sufficient to prevent the carryover of in-process contaminants
to the drug substance or product. Consistent production of a reasonably pure reagent should be demonstrated to assure adequate
and uninterrupted performance in the production of the drug substance. Downward trends of the MAb lots in purity, integrity,
and binding properties have been investigated. Chemical impurities originated from buffers, columns, and media, as well as
host cell protein, should be monitored and minimized to avoid contamination of the bulk drug substance.