Mary Christina Thomson - Mar 4, 2022 Form 4 Insider Report for Sierra Oncology, Inc. (SRRA)

Role: General Counsel, CCO & Sec'y
Signature: /s/ Mary Christina Thomson
Stock symbol: SRRA
Transactions as of: Mar 4, 2022
Transactions value $: -$35,116
Form type: 4
Date filed: 3/4/2022, 03:12 PM
Previous filing: Feb 4, 2022
Next filing: Mar 14, 2022

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SRRA	Common Stock	Options Exercise	$26.1K	+2K		$13.04	2K	Mar 4, 2022	Direct
transaction	SRRA	Common Stock	Sale	-$61.2K	-2K	-100%	$30.60	0	Mar 4, 2022	Direct	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	SRRA	Stock Option (Right to Buy)	Options Exercise	$0	+2K		$0.00^*	0	Mar 4, 2022	Common Stock	2K	$13.04	Direct	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 22, 2020. The Reporting Person is subject to a Lock-Up Letter Agreement that expires on April 26, 2022. The sale of shares is a permissible exemption under the terms of the Lock-Up Letter Agreement.
F2	On July 28, 2021, the option vested as to 25% of the total shares granted on July 28, 2020, with the remaining shares from that grant vesting in equal monthly installments over the following 36 months, with 100% of the total shares vested on July 28, 2024, subject to the Reporting Person's provision of service to the Issuer on each vesting date.