Item 1.01 Entry into a Material Definitive Agreement.

Regeneron Pharmaceuticals, Inc. (“Regeneron”) entered into two agreements with Novartis Pharma AG and Novartis Pharmaceuticals Corporation (collectively, “Novartis”), effective June 8, 2009, terminating and replacing a March 2003 Collaboration, License and Option Agreement (the “2003 Collaboration Agreement”). Under the 2003 Collaboration Agreement, Regeneron had the right to opt in to the development and commercialization, including the right to receive a specified share of the profits from sales, of Novartis’ interleukin-1 (IL-1) antibody product candidate, and Novartis had the right to opt in to the development and commercialization, including the right to receive a specified share of the profits from sales, of Regeneron’s second-generation IL-1 Trap.

Under the first agreement, called the IL-1 Antibody Termination Agreement, the parties terminated the 2003 Collaboration Agreement, including the opt-in rights discussed above. In exchange for eliminating Regeneron’s right to opt in to the development and commercialization of Novartis’ IL-1 antibody product candidate, Novartis agreed to pay Regeneron tiered royalties on future aggregate, worldwide annual net sales (“annual sales”) of certain Novartis IL-1 antibody products, including canakinumab (ACZ885), a fully human IL-1 antibody currently under regulatory review to treat cryopyrin-associated periodic syndrome (CAPS). The multi-tiered royalty rates in the agreement start at 4% and reach 15% when annual sales exceed $1.5 billion.

Under the second agreement, called the Trap-2 Termination Agreement, in exchange for eliminating Novartis’ right to opt in to the development and commercialization of Regeneron’s second generation IL-1 Trap, Regeneron agreed to pay Novartis tiered royalties on any future worldwide net sales of certain IL-1 blocking products sold by Regeneron, with the exception of Regeneron’s IL-1 Trap (also known as ARCALYST^® (rilonacept) Injection for Subcutaneous Use), which is marketed and sold in the United States for the treatment of CAPS and is in Phase 3 clinical trials for the treatment of gout. In February 2004, Novartis terminated the 2003 Collaboration Agreement with respect to Regeneron’s IL-1 Trap. The royalty terms under the Trap-2 Termination Agreement are identical to those of the IL-1 Antibody Termination Agreement based on aggregate, worldwide, annual net sales of Regeneron’s covered products.

The press release dated June 11, 2009 issued by Regeneron announcing the execution of the two agreements by Regeneron and Novartis is attached as Exhibit 99.1 and is incorporated by reference into this Item 1.01.

Item 1.02 Termination of a Material Definitive Agreement.

The information set forth under Item 1.01, including the press release dated June 11, 2009 and attached as Exhibit 99.1, is incorporated by reference into this Item 1.02. The parties determined that it was in their best interest to terminate the 2003 Collaboration Agreement and replace it with the IL-1 Antibody Termination Agreement and the Trap-2 Termination Agreement as described under Item 1.01 above.