The Company is party to a global, strategic collaboration with Sanofi to research, develop, and commercialize fully human monoclonal antibodies, which currently consists of Dupixent® (dupilumab), Kevzara® (sarilumab), and itepekimab.

Sanofi is generally responsible for funding 80% to 100% of agreed-upon development costs. The Company is obligated to reimburse Sanofi for 30% to 50% of worldwide development expenses that were funded by Sanofi (i.e., "development balance") based on the Company's share of collaboration profits; however, the Company is only required to apply 20% of its share of profits from the collaboration each calendar quarter to reimburse Sanofi for these development expenses. As of September 30, 2024, the Company's contingent reimbursement obligation to Sanofi under the collaboration was approximately $1.810 billion.

Sanofi leads commercialization activities for products under the collaboration, subject to the Company's right to co-commercialize such products. During the three months ended September 30, 2023, the Company earned the final $50.0 million sales-based milestone from Sanofi upon aggregate annual sales of antibodies outside the United States exceeding $3.0 billion on a rolling twelve-month basis.


	Statement of Operations Classification	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions)		2024		2023		2024		2023
Regeneron's share of profits	Collaboration revenue	$	1,088.3	$	863.0	$	2,880.6	$	2,250.6
Sales-based milestones earned	Collaboration revenue	$	—	$	50.0	$	—	$	50.0
Reimbursement for manufacturing of commercial supplies	Collaboration revenue	$	175.1	$	151.5	$	438.2	$	506.0
Regeneron's obligation for its share of Sanofi R&D expenses, net of reimbursement of R&D expenses	(R&D expense)	$	(7.8)	$	(25.8)	$	(35.5)	$	(66.7)
Reimbursement of commercialization-related expenses	Reduction of SG&A expense	$	169.0	$	135.5	$	459.3	$	384.0

The Company is party to a license and collaboration agreement with Bayer for the global development and commercialization of EYLEA 8 mg (aflibercept 8 mg) and EYLEA (aflibercept) outside the United States. Agreed-upon development expenses incurred by the Company and Bayer are generally shared equally. Bayer is responsible for commercialization activities outside the United States, and the companies share equally in profits from such sales. Within the United States, the Company is responsible for commercialization and retains profits from such sales.


	Statement of Operations Classification	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions)		2024		2023		2024		2023
Regeneron's share of profits	Collaboration revenue	$	367.6	$	349.9	$	1,054.5	$	1,031.0
Reimbursement for manufacturing of ex-U.S. commercial supplies	Collaboration revenue	$	23.2	$	27.2	$	67.4	$	79.7
Regeneron's obligation for its share of Bayer R&D expenses, net of reimbursement of R&D expenses	(R&D expense)	$	(11.8)	$	(9.7)	$	(35.2)	$	(35.1)

The Company is a party to a collaboration agreement with Roche to develop, manufacture, and distribute the casirivimab and imdevimab antibody cocktail (known as REGEN-COV® in the United States and Ronapreve™ in other countries). Under the terms of the collaboration agreement, the Company has the right to distribute the product in the United States while Roche has the right to distribute the product outside the United States. The parties share gross profits from worldwide sales.


	Statement of Operations Classification	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions)		2024		2023		2024		2023
Global gross profits earned in connection with sales of Ronapreve	Collaboration revenue	$	0.5	$	—	$	1.4	$	222.2
Other	Collaboration revenue	$	—	$	(5.7)	$	—	$	(9.5)

Contract balances in the Company's Balance Sheets in connection with the Roche collaboration were not material as of September 30, 2024 and December 31, 2023.

In addition to the collaboration and license agreements discussed above, the Company has various other collaboration and license agreements that are not individually significant to its operating results or financial condition at this time. Pursuant to the terms of those agreements, the Company may be required to pay, or it may receive, additional amounts contingent upon the occurrence of various future events (e.g., upon the achievement of various development and commercial milestones), which in the aggregate could be significant. The Company may also incur, or get reimbursed for, significant research and development costs.

During the three and nine months ended September 30, 2024, the Company recorded to Acquired in-process research and development expense a $45.0 million development milestone in connection with the Company's collaboration agreement with Sonoma Biotherapeutics, Inc.

During the three and nine months ended September 30, 2023, the Company recorded to Acquired in-process research and development expense a $100.0 million development milestone in connection with the Company's collaboration agreement with Alnylam Pharmaceuticals, Inc. Acquired in-process research and development expense for the nine months ended September 30, 2023 also included a $45.0 million up-front payment in connection with the Company's collaboration agreement with Sonoma.