CUSIP No. 279870109 13D Page 16 of 24 Pages

EXHIBIT A

AGREEMENT

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 13D need be filed with respect to the ownership by each of the undersigned of shares of stock of PDS Biotechnology Corporation.

March 25, 2019

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

CUSIP No. 279870109 13D Page 17 of 24 Pages

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

/s/ Craig L. Slutzkin

Craig L. Slutzkin

As attorney-in-fact

* This Schedule 13D was executed by Craig L. Slutzkin on behalf of the individuals listed above pursuant to Powers of Attorney, copies of which are on file with the appropriate agencies.

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