13D Filing: OrbiMed Advisors and Arsanis Inc (ASNS)

Item 1.

Security and Issuer

This Schedule 13D (the “Statement”) relates to the common stock, par value $0.001 per share of Arsanis, Inc. (the “Common Stock”), a corporation organized under the laws of Delaware (the “Issuer”), with its principal executive offices located at 890 Winter Street, Suite 230, Waltham, Massachusetts 02451.  The Common Stock is listed on the NASDAQ Global Market under the ticker symbol “ASNS.”  Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable.

Item 2.

Identity and Background

(a)          This Statement is being filed by OrbiMed Advisors LLC (“Advisors”), a limited liability company organized under the laws of Delaware, OrbiMed Capital GP IV LLC (“GP IV”), a limited liability company organized under the laws of Delaware, and Samuel D. Isaly (“Isaly”), an individual (collectively, the “Reporting Persons”).

(b) – (c)          Advisors, a registered investment adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of GP IV, which is the sole general partner of OrbiMed Private Investments IV, LP (“OPI IV”), which holds Common Stock, as more particularly described in Item 6 below.  Advisors has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022.

GP IV has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022.

Isaly, a natural person, owns a controlling interest in Advisors.

The directors and executive officers of Advisors and GP IV are set forth on Schedules I and II, attached hereto.  Schedules I and II set forth the following information with respect to each such person:

(i)

name;

(ii)

business address;

(iii)

present principal occupation or employment and the name, principal business and address of any corporation or other organization in which such employment is conducted;

(iv)

citizenship.

(d) – (e)          During the last five years, neither the Reporting Persons nor any Person named in Schedule I or II have been (i) convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or (ii) a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f)          Isaly is a citizen of the United States.