Organization and Nature of Business

9 Months Ended

Dec. 31, 2011

1.	Organization and Nature of Business

Repligen Corporation (“Repligen” or the “Company”) is a world-leading supplier of critical biologic products used to manufacture biologic drugs. The Company also applies its expertise in biologic product development to SecreFlo^TM, for which the Company’s first new drug application (“NDA”) has been submitted and accepted for priority review by the U.S. Food and Drug Administration (“FDA”) and for which we have submitted a marketing authorization application (“MAA”) to the European Medicines Agency (“EMA”). The Company also has two central nervous system (“CNS”) rare disease clinical programs underway in Friedreich’s ataxia and spinal muscular atrophy. In addition, the Company has out-licensed certain biologics intellectual property from which we receive royalties from Bristol-Myers Squibb Company (“Bristol”) on their net sales in the United States of their product Orencia^®.

As previously announced, in 2011 the Company changed its fiscal year end from March 31 to December 31. This Transition Report on Form 10-K reports the Company’s financial results for the nine-month period from April 1, 2011 through December 31, 2011, which is referred to as “the nine-month fiscal year ended December 31, 2011” throughout this report. Following this Transition Report, the Company will report on a twelve-month fiscal year beginning on January 1 and ending on December 31 of each year.

The Company is subject to a number of risks typically associated with companies in the biotechnology industry. These risks principally include the Company’s dependence on collaborative arrangements, development by the Company or its competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with the FDA and other governmental regulations and approval requirements, as well as the ability to grow the Company’s business and obtain adequate funding to finance this growth.