Dear Colleagues and Stockholders: I am writing to let you know that I am taking a temporary medical leave of absence from Lyell as a result of a recent health situation. I expect to make a full recovery and to return in

Dear Colleagues and Stockholders:

I am writing to let you know

that I am taking a temporary medical leave of absence from Lyell as a result of a recent health situation. I expect to make a full recovery and to return in early 2022.

I want to personally thank all Lyellites for the incredible work they are doing to advance the ambitious and important mission of Lyell. I d also like to

thank my fellow Board members for their support.

Knowing that the company is led by Liz and a truly outstanding leadership team, and that the team is

supported by an amazing group of employees who will continue to advance our important mission - curing solid tumor cancers - enables me to focus fully on my health. I am confident that tremendous progress will be made during my leave, and I

can t wait to catch up upon my return.

My family and I deeply appreciate your good wishes and support. Please know that I will be taking a break

from general business communications (something new for me!) but I will stay in touch with Liz. I thank you for respecting my and my family s privacy during this time.