Revenues

3 Months Ended

Mar. 31, 2025

Revenue from Contract with Customer [Abstract]

Revenues

Note 5: Revenue

Product Revenue

Revenue by product is summarized as follows:

	For the Three Months Ended March 31,
	2025						2024
(In millions)	United States		Rest of World		Total		United States		Rest of World		Total
Multiple Sclerosis:
TECFIDERA	$	39.8	$	166.3	$	206.1	$	43.7	$	210.6	$	254.3
VUMERITY	117.1		21.7		138.8		105.9		21.6		127.5
Total Fumarate	156.9		188.0		344.9		149.6		232.2		381.8
AVONEX	108.6		58.2		166.8		111.2		67.3		178.5
PLEGRIDY	24.1		35.4		59.5		28.6		36.5		65.1
Total Interferon	132.7		93.6		226.3		139.8		103.8		243.6
TYSABRI	200.8		180.7		381.5		213.8		217.5		431.3
FAMPYRA(1)	—		0.3		0.3		—		19.2		19.2
Subtotal: Multiple Sclerosis	490.4		462.6		953.0		503.2		572.7		1,075.9
Rare Disease:
SPINRAZA	154.4		269.5		423.9		148.5		192.8		341.3
SKYCLARYS(2)	69.1		54.8		123.9		73.0		5.0		78.0
QALSODY(3)	7.5		8.0		15.5		4.4		0.2		4.6
Subtotal: Rare Disease	231.0		332.3		563.3		225.9		198.0		423.9
Biosimilars:
BENEPALI	—		111.3		111.3		—		118.7		118.7
IMRALDI	—		47.4		47.4		—		54.8		54.8
FLIXABI	—		13.1		13.1		—		17.8		17.8
BYOOVIZ	4.2		4.7		8.9		3.7		1.9		5.6
TOFIDENCE	0.1		—		0.1		—		—		—
Subtotal: Biosimilars	4.3		176.5		180.8		3.7		193.2		196.9
Other:
ZURZUVAE	27.7		—		27.7		12.4		—		12.4
Other(4)	0.4		1.3		1.7		0.9		1.9		2.8
Subtotal: Other	28.1		1.3		29.4		13.3		1.9		15.2
Total product revenue, net	$	753.8	$	972.7	$	1,726.5	$	746.1	$	965.8	$	1,711.9

(1) Effective January 1, 2025, our collaboration and license agreement for FAMPYRA global commercialization rights was terminated.

(2) SKYCLARYS became commercially available in the E.U. during the first quarter of 2024.

(3) QALSODY became commercially available in the E.U. during the second quarter of 2024.

(4) Other includes FUMADERM and ADUHELM.

We recognized revenue from two wholesalers accounting for 25.9% and 14.1% of gross product revenue for the three months ended March 31, 2025, compared to 25.6% and 11.7% of gross product revenue for the three months ended March 31, 2024.

An analysis of the change in reserves for discounts and allowances is summarized as follows:

(In millions)	Discounts		Contractual Adjustments		Returns		Total
Balance, December 31, 2024	$	162.7	$	880.8	$	48.1	$	1,091.6
Current provisions relating to sales in current year	185.7		689.7		5.6		881.0
Adjustments relating to prior years	1.4		(31.4)		3.9		(26.1)
Payments/credits relating to sales in current year	(118.3)		(229.6)		(0.1)		(348.0)
Payments/credits relating to sales in prior years	(64.9)		(359.5)		(3.7)		(428.1)
Balance, March 31, 2025	$	166.6	$	950.0	$	53.8	$	1,170.4

The total reserves above, which are included in our condensed consolidated balance sheets, are summarized as follows:

(In millions)	As of March 31, 2025		As of December 31, 2024
Reduction of accounts receivable	$	205.2	$	154.1
Component of accrued expense and other	965.2		937.5
Total revenue-related reserves	$	1,170.4	$	1,091.6

Revenue from Anti-CD20 Therapeutic Programs

Revenue from anti-CD20 therapeutic programs is summarized in the table below. For the purposes of this footnote, we refer to RITUXAN and RITUXAN HYCELA collectively as RITUXAN.

	For the Three Months Ended March 31,
(In millions)	2025		2024
Royalty revenue on sales of OCREVUS	$	288.8	$	302.7
Biogen’s share of pre-tax profits in the U.S. for RITUXAN, GAZYVA and LUNSUMIO	83.7		87.1
Other revenue from anti-CD20 therapeutic programs	5.7		4.2
Total revenue from anti-CD20 therapeutic programs	$	378.2	$	394.0

For additional information on our collaboration arrangements with Genentech, please read Note 19, Collaborative and Other Relationships, to these condensed consolidated financial statements.

Alzheimer's Collaboration Revenue

Alzheimer's collaboration revenue consists of our 50.0% share of LEQEMBI product revenue, net and cost of sales, including royalties, as we are not the principal. We began recognizing Alzheimer's collaboration revenue upon the accelerated approval of LEQEMBI in the U.S. during the first quarter of 2023.

For the three months ended March 31, 2025 and 2024, we recognized approximately $33.0 million and $2.8 million, respectively, of Alzheimer's collaboration revenue within our condensed consolidated statements of income.

For additional information on our collaboration arrangements with Eisai, please read Note 19, Collaborative and Other Relationships, to these condensed consolidated financial statements.

Contract Manufacturing, Royalty and Other Revenue

Contract manufacturing, royalty and other revenue is summarized as follows:

	For the Three Months Ended March 31,
(In millions)	2025		2024
Contract manufacturing revenue	$	282.3	$	152.2
Royalty and other revenue	11.0		29.6
Total contract manufacturing, royalty and other revenue	$	293.3	$	181.8

Contract Manufacturing Revenue

Contract manufacturing revenue primarily reflects amounts earned under contract manufacturing agreements with our strategic customers and batches of LEQEMBI related to our collaboration with Eisai.

Royalty and Other Revenue

Royalty and other revenue primarily reflects royalty revenue on biosimilar products from our license arrangements with Samsung Bioepis and royalties we receive from net sales on products related to patents that we have out-licensed.

For additional information on our license arrangements with Samsung Bioepis and our collaboration arrangements with Eisai, please read Note 19, Collaborative and Other Relationships, to these condensed consolidated financial statements.