Propel Bio Management SC 13D Eiger BioPharmaceuticals / Propel Bio Management ownership change

Exhibit 99.1

JOINT FILING AGREEMENT

This will confirm the agreement by and among the undersigned that the Schedule 13D filed with the Securities and Exchange Commission on or about the date hereof with respect to the beneficial ownership by the undersigned of the common stock, par value $0.001 per share, of Eiger BioPharmaceuticals, Inc., a Delaware corporation, is being filed, and all amendments thereto will be filed, on behalf of each of the persons and entities named below who is named as a reporting person therein in accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

Date: October 20, 2023
	PROPEL BIO MANAGEMENT LLC
	By:	/s/ Leen Kawas

Name:	Leen Kawas
Title:	Managing Member

/s/ Leen Kawas

Leen Kawas

RICHARD AND SUZANNE KAYNE LIVING
TRUST DTD 01/14/1999
By:	/s/ Richard Kayne

Name:	Richard Kayne
Title:	Trustee

/s/ Richard Kayne

Richard Kayne

PROPEL BIO PARTNERS LLC
By:	/s/ Leen Kawas

Name:	Leen Kawas
Title:	Managing Member