13D Filing: Baker Bros. Advisors and Erytech Pharma SA (ADR) (ERYP)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

 

SCHEDULE 13D

Under the Securities Exchange Act of
1934

(Amendment No.    )*

ERYTECH Pharma S.A.

(Name of Issuer)

Ordinary Shares, nominal value €0.10
per share

(Title of Class of Securities)

29604W108

(CUSIP number)

Alexandra A. Toohey

Chief Financial Officer

Baker Bros. Advisors LP

860 Washington Street, 3^rd Floor

New York, NY 10014

(212) 339-5690

(Name, address and telephone number of person
authorized to receive notices and communications)

November 10, 2017

(Date of event which requires filing of
this statement)

If
the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule
13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box. ¨

(Continued on the following pages)

Note: Schedules filed in paper format shall include a
signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to
be sent.

* The remainder of this cover page shall be filled out for
a reporting person’s initial filing on this form with respect to the subject class of securities, and for any
subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page
shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”)
or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however,
see the Notes).