Revenues (Tables)

3 Months Ended

Mar. 31, 2026

Revenue from Contract with Customer [Abstract]

Revenue by product is summarized as follows:


	For the Three Months Ended March 31,
	2026						2025
(In millions)	United States		Rest of World		Total		United States		Rest of World		Total
Multiple Sclerosis:
TECFIDERA	$	31.4	$	78.1	$	109.5	$	39.8	$	166.3	$	206.1
VUMERITY	153.4		25.6		179.0		117.1		21.7		138.8
Total Fumarate	184.8		103.7		288.5		156.9		188.0		344.9
AVONEX	108.5		54.7		163.2		108.6		58.2		166.8
PLEGRIDY	24.3		40.0		64.3		24.1		35.4		59.5
Total Interferon	132.8		94.7		227.5		132.7		93.6		226.3
TYSABRI	241.8		199.7		441.5		200.8		180.7		381.5
FAMPYRA(1)	—		—		—		—		0.3		0.3
Subtotal: Multiple Sclerosis	559.4		398.1		957.5		490.4		462.6		953.0

Rare Disease:
SPINRAZA	142.2		231.8		374.0		154.4		269.5		423.9
SKYCLARYS	71.8		78.9		150.7		69.1		54.8		123.9
QALSODY	10.5		22.0		32.5		7.5		8.0		15.5
Subtotal: Rare Disease	224.5		332.7		557.2		231.0		332.3		563.3

Biosimilars:
BENEPALI	—		122.1		122.1		—		111.3		111.3
IMRALDI	—		49.6		49.6		—		47.4		47.4
FLIXABI	—		10.5		10.5		—		13.1		13.1
BYOOVIZ(2)	—		—		—		4.2		4.7		8.9
TOFIDENCE(2)	—		—		—		0.1		—		0.1
Subtotal: Biosimilars	—		182.2		182.2		4.3		176.5		180.8

Other:
ZURZUVAE	55.3		0.1		55.4		27.7		—		27.7


Other(3)	—		—		—		0.4		1.3		1.7
Subtotal: Other	55.3		0.1		55.4		28.1		1.3		29.4
Total product revenue, net	$	839.2	$	913.1	$	1,752.3	$	753.8	$	972.7	$	1,726.5

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

(2) In 2025 we completed the sale of our rights to TOFIDENCE and BYOOVIZ.

(3) Other includes FUMADERM and ADUHELM.

Analysis of change In reserves

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, 2025	$	115.7	$	1,046.1	$	49.0	$	1,210.8
Current provisions relating to sales in current year	214.0		683.7		7.3		905.0
Adjustments relating to prior years	0.8		(28.4)		10.4		(17.2)
Payments/credits relating to sales in current year	(133.4)		(255.3)		(0.1)		(388.8)
Payments/credits relating to sales in prior years	(92.3)		(426.0)		(14.9)		(533.2)
Balance, March 31, 2026	$	104.8	$	1,020.1	$	51.7	$	1,176.6

Total reserves included in consolidated balance sheets

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


(In millions)	As of March 31, 2026		As of December 31, 2025
Component of accrued expense and other	$	961.1	$	1,000.4
Reduction of accounts receivable	215.5		210.4
Total revenue-related reserves	$	1,176.6	$	1,210.8

Revenues 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)	2026		2025
Royalty revenue on sales of OCREVUS	$	317.2	$	288.8
Biogen’s share of pre-tax profits in the U.S. for RITUXAN, GAZYVA and LUNSUMIO	94.7		83.7
Other revenue from anti-CD20 therapeutic programs	7.2		5.7
Total revenue from anti-CD20 therapeutic programs	$	419.1	$	378.2

Other revenues

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


	For the Three Months Ended March 31,
(In millions)	2026		2025
Contract manufacturing revenue	$	237.2	$	282.3
Royalty and other revenue	9.7		11.0
Total contract manufacturing, royalty and other revenue	$	246.9	$	293.3