Exhibit A AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13D

Exhibit A

AGREEMENT REGARDING THE JOINT FILING OF

SCHEDULE 13D

The undersigned, being duly authorized thereunto, hereby execute this agreement as an exhibit to this Schedule 13D to evidence the agreement of the below-named parties, in accordance with the rules promulgated pursuant to the Securities Exchange Act of 1934, to file this Schedule jointly on behalf of each such party.

Date: June 11, 2018

NEW LEAF VENTURES III, L.P.
By:		New Leaf Venture Associates III, L.P.
		By: New Leaf Venture Management III, L.L.C.
By:		/s/ Xxxxx Xxxxxxxx
		Chief Financial Officer
NEW LEAF BIOPHARMA OPPORTUNITIES II, L.P.
By:		New Leaf BPO Associates II, L.P.
		By: New Leaf BPO Management II, L.L.C.
By:		/s/ Xxxxx Xxxxxxxx
		Chief Financial Officer
NEW LEAF VENTURE ASSOCIATES III, L.P.
By:		New Leaf Venture Management III, L.L.C.
By:		/s/ Xxxxx Xxxxxxxx
		Chief Financial Officer
NEW LEAF BPO ASSOCIATES II, L.P.
By:		New Leaf BPO Management II, L.L.C.
By:		/s/ Xxxxx Xxxxxxxx
		Chief Financial Officer
NEW LEAF VENTURE MANAGEMENT III, L.L.C.
By:		/s/ Xxxxx Xxxxxxxx
		Chief Financial Officer
NEW LEAF BPO MANAGEMENT II, L.L.C.
By:		/s/ Xxxxx Xxxxxxxx
		Chief Financial Officer

XXXX XXXXXXXXX
By:		*
		Xxxx Xxxxxxxxx
XXXXXX X. XXXX
By:		*
		Xxxxxx X. Xxxx
XXXXX X. XXXXX
By:		*
		Xxxxx X. Xxxxx
XXXXX X. XXXXX
By:		*
		Xxxxx X. Xxxxx

*By:		/s/ Xxxxx Xxxxxxxx
Name:		Xxxxx Xxxxxxxx
		Attorney-in-Fact

[This Schedule 13D was executed pursuant to a Power of Attorney. Note that copies of the applicable Powers of Attorney are already on file with the appropriate agencies.]