RTW Investments SC 13G Chardan Healthcare Acquisition 2 / RTW INVESTMENTS ownership change

Exhibit 1

Joint Filing Statement

Pursuant to Rule 13d-1(k)(1)

The undersigned hereby consent and agree to the joint filing of Schedule 13G under the Securities Exchange Act of 1934, as amended, with respect to the Common Stock, par value $0.001 per share of Exagen Inc. beneficially owned by them, together with any or all amendments thereto, when and if appropriate. The parties hereto further consent and agree to file this Joint Filing Statement pursuant to Rule13d-1(k)(1)(iii) as an exhibit to Schedule 13G, thereby incorporating the same into such Schedule13G.

This Joint Filing Statement may be terminated by any of the undersigned upon written notice or such lesser period of notice as the undersigned may mutually agree.

Dated: July 29, 2021
	RTW Investments, LP
	By:	/s/ Roderick Wong
		Roderick Wong, Managing Partner
	RTW Master Fund, Ltd.
	By:	/s/ Roderick Wong
		Roderick Wong, Director
	Roderick Wong
	By:	/s/ Roderick Wong
		Roderick Wong, Individually