Exhibit 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k), as promulgated under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them a Statement on Schedule 13D (including amendments thereto) with regard to the common stock of AMGN Pharmaceuticals, Inc., and further agree that this Joint Filing Agreement be included as an Exhibit to such joint filings. In evidence thereof, the undersigned, being duly authorized, hereby execute this Joint Filing Agreement as of October 9, 2020.

Dated: October 9, 2020

MAGNETAR FINANCIAL LLC

By: Magnetar Capital Partners LP, its Sole Member

By:	/s/ Alec N. Litowitz
	Name:	Alec N. Litowitz
	Title:	Manager of Supernova Management LLC, the General Partner of Magnetar Capital Partners LP

MAGNETAR CAPITAL PARTNERS LP

By:	/s/ Alec N. Litowitz
	Name:	Alec N. Litowitz
	Title:	Manager of Supernova Management LLC, the General Partner of Magnetar Capital Partners LP

SUPERNOVA MANAGEMENT LLC

By:	/s/ Alec N. Litowitz
	Name:	Alec N. Litowitz
	Title:	Manager

/s/ Alec N. Litowitz
Alec N. Litowitz

AMAG PHARMACEUTICALS, INC. SC 13D