Segment Reporting (Tables)

12 Months Ended

Dec. 31, 2025

Segment Reporting [Abstract]

Financial Information of Reportable Segment

Financial information of the Company’s reportable segment for 2025 and 2024 are as follows (in thousands):

	2025			2024
Research and development ("R&D") programs:
CLN-049	$	17,088		$	7,508
CLN-418		—			6,471
CLN-617		6,778			4,403
CLN-619		23,118			25,096
CLN-978		23,074			14,833
Early-stage programs		6,286			5,938
Velinotamig		1,619			—
Zipalertinib		33,548			31,875
Total R&D program expense		111,511			96,124
Equity-based compensation		36,040			37,824
R&D personnel and operations		39,986			31,532
General and administrative personnel		13,572			14,578
License agreement obligations		20,303			100
Other segment expenses(1)		20,236			16,761
Loss from operations		(241,648	)		(196,919	)
Other income (expense):
Interest income		22,212			29,660
Other income (expense), net		(443	)		(199	)
Net loss before income taxes		(219,879	)		(167,458	)
Income tax expense (benefit)		—			117
Net loss		(219,879	)		(167,575	)
Net loss attributable to noncontrolling interests		—			(192	)
Net loss attributable to Cullinan	$	(219,879	)	$	(167,383	)

(1)Other segment expenses for 2025 and 2024 include legal fees relating to patent and corporate matters; professional fees for accounting, auditing, tax, and administrative consulting services; insurance costs; marketing expenses; depreciation; and other operating costs.