EXHIBIT 1

AGREEMENT REGARDING JOINT FILING OF SCHEDULE 13G

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of shares of Common Stock of Passage Bio, Inc.

Date: February 11, 2021

NEW LEAF VENTURES III, L.P.
By:	NEW LEAF VENTURE ASSOCIATES III, L.P.
	Its General Partner
	By:	NEW LEAF VENTURE MANAGEMENT III, L.L.C.
		Its General Partner
		By:	/s/ Craig L. Slutzkin
			Craig L. Slutzkin
			Chief Financial Officer
NEW LEAF VENTURE ASSOCIATES III, L.P.
By:	NEW LEAF VENTURE MANAGEMENT III, L.L.C.
	Its General Partner

By:	/s/ Craig L. Slutzkin
	Craig L. Slutzkin
	Chief Financial Officer

NEW LEAF VENTURE MANAGEMENT III, L.L.C.
By:	/s/ Craig L. Slutzkin
	Craig L. Slutzkin
	Chief Financial Officer
*
Vijay K. Lathi
*
Ronald M. Hunt

/s/ Craig L. Slutzkin

* Craig L. Slutzkin

As attorney-in-fact

* This Schedule 13G was executed by Craig L. Slutzkin on behalf of the individuals listed above pursuant to Powers of Attorney. Note that copies of the applicable Powers of Attorney are already on file with the appropriate agencies.