Adds details on gene therapies in paragraph 8-9

Feb 21 (Reuters) - Gene therapy maker bluebird bio BLUE.O on Friday agreed to be taken private by Carlyle CG.O and SK Capital Partners at a discount, ending its tumultuous journey in the public markets as it struggled with a severe cash crunch.

Shares of the company declined 36% in early trading after bluebird accepted a $3 per share cash offer - a discount of 57.4% to their last close and implying an equity value of $29.16 million.

Before bluebird's troubles started, its shares had traded at about $150 in 2018. The stock fell 70% last year.

The company first raised going concern doubts three years ago. Last year, it laid off a quarter of its workforce to focus on the marketing and launch of three of gene therapies, including Lyfgenia, a closely watched treatment for sickle cell disease.

The go-private deal will now provide the "primary capital" required to scale bluebird's commercialization efforts for gene therapies.

The investment firms have offered an additional $6.84 per share, contingent upon bluebird achieving certain sales milestones, which represents a payment of about $66.48 million.

Uptake of gene therapies for sickle cell disease has been slow, with early use seen mainly in those with severe disease, partly due to the long period of time involved for treatment.

As of November, 57 patients had started treatment on all three bluebird therapies, including 17 on Lyfgenia. Its other two commercial products are Zynteglo and Skysona, both approved in the U.S. in 2022.

Skysona is approved to treat a rare neurological disorder, and Zynteglo for a blood disorder called beta-thalassemia.

Bluebird reported a cash balance of about $118.7 million, including restricted cash of about $48 million, as of September 30, 2024 - which was expected to fund operations into the first quarter of 2025.

(Reporting by Sneha S K and Bhanvi Satija; Editing by Shinjini Ganguli)

((Sneha.SK@thomsonreuters.com;))