Monoclonal antibodies (mAbs) have the potential to treat a wide range of diseases. They possess the ability to bind target molecules in a highly specific and effective manner. Recently, great technological advances have been made to enhance the therapeutic effects of these drugs, making treatment cheaper, easier, and more effective while allowing companies to profit significantly. As a Contract Manufacturing Organization (CMO) for these products, we offer the newest technology and many flexible options for producing these proteins. Our facility is designed to produce protein products in Chinese Hamster Ovary (CHO) cells, followed by modification and purification steps. We present the option to cleave smaller antigen binding fragments (Fab) from the mAb product, removing the crystallizable fragment (Fc) which can interfere with the binding specificity of the drug. We also offer the option for polyethylene glycosylation (PEGylation), which has been shown to improve the effectiveness of these drugs. The attachment of a polyethylene glycol (PEG) molecule to the protein enhances its circulation time in the human body so that less frequent doses are needed. To demonstrate the capabilities of this flexible facility, we have modeled the production of an innovative PEGylated anti-TNF-α mAb. Celltech and Pfizer currently have similar products in Phase III clinical trials; and UCB Incorporated’s Cimzia® recently received FDA approval for the first humanized PEGylated anti-TNF-α Fab’ therapeutic protein. Many non- PEGylated TNF-α inhibitor mAbs are currently on the market to treat pathologies including rheumatoid arthritis and Crohn’s disease. PEGylated products have a clear advantage over these drugs. Our facility can produce up to 55 batches of protein product a year for a maximum yield of 993 kg. For economic analysis of this product, sales from the first year of Cimzia® were considered since this product is almost identical to the one being modeled. Producing at 75% of the total design capacity, this facility has a NPV of $1,319,592,100, an IRR of 33.51% and an ROI of 53.0%. This level of production would leave a significant amount of time remaining for other products to be manufactured as well. The additional products that the facility will produce will be mAbs of all forms (i.e. cleaved, uncleaved, PEGylated, non-PEGylated) that are protected under IP for small biotech firms that do not have the capital to build such facilities. Currently, small biotech firms are producing 81 mAbs and are looking to license production for their Phase III molecules. Clearly, this will become a very profitable CMO as we would be able to capture much of this demand. A major threat looming over the mAb market, however, is the production of small molecular inhibitors, which are currently in Phase I and Phase II clinical trials. Such molecules may be able to capture the full market since they would not only have significant delivery advantages over TNF-α inhibitors, which require injection, but also might have an enhanced side effect profile compared with biologics.