Adverum Biotechnologies, Inc. entered into a collaboration, option and license agreement with Editas Medicine, Inc., pursuant to which Adverum and Editas collaborate on certain studies using adeno-associated viral vectors in connection with Editas' genome editing technology and Adverum granted to Editas an exclusive option to obtain certain exclusive rights to use Adverum's proprietary vectors in up to five ophthalmic indications. On January 25, 2018, Adverum and Editas entered into an amendment to the collaboration, option and license agreement. In consideration for entering into the amendment, Editas will make a one-time payment to Adverum of $500,000.

Under the terms of the agreement, as amended, Editas may exercise the option with respect to a designated initial indication until September 30, 2018. With respect to the four other indications, Editas may exercise the option until the fourth anniversary of the effective date, provided that the option will expire on the third anniversary of the effective date if Editas has not exercised the option with respect to the initial indication or any other indication by such date. Upon Editas' timely exercise of the option with respect to the designated initial indication, Editas will pay Adverum a $1.3 million fee.

For the first additional indication for which Editas timely exercises its option, Editas will pay Adverum a $1.5 million fee. Upon each subsequent exercise of the option, Editas will pay Adverum a $1.0 million fee per indication.