13G Filing: Biotechnology Value Fund LP and Contrafect Corp (CFRX)

 UNITED STATES

SECURITIES AND EXCHANGE
COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULES 13d-1(b), (c),
AND (d) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2(b)

(Amendment No.
)¹

Check the appropriate box
to designate the rule pursuant to which this Schedule is filed:

(1)       Includes 145,947 shares of Common Stock issuable upon the exercise
of certain Warrants (defined in Item 4).

ContraFect Corporation, a Delaware corporation (the “Issuer”).

28 Wells Avenue, 3rd Floor

Yonkers, New York 10701

Biotechnology Value Fund, L.P. (“BVF”)

1 Sansome Street, 30^th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Fund II, L.P. (“BVF2”)

1 Sansome Street, 30^th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Trading Fund OS
LP (“Trading Fund OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF Partners OS Ltd. (“Partners
OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF Partners L.P. (“Partners”)

1 Sansome Street, 30th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF Inc.

1 Sansome Street, 30^th Floor

San Francisco, California 94104

Citizenship: Delaware

Mark N. Lampert (“Mr. Lampert”)

1 Sansome Street, 30^th Floor

San Francisco, California 94104

Citizenship: United States

Each of the foregoing is referred to
as a “Reporting Person” and collectively as the “Reporting Persons.”

Common Stock, par value $0.0001 per share (the “Common
Stock”)

212326102

The Reporting Persons hold 3,500,000
warrants, exercisable for an aggregate of 1,750,000 shares of Common Stock (the “Warrants”). Each Warrant is exercisable
for ½ share of Common Stock. The Warrants are only exercisable to the extent that the holder, together with its affiliates
and any other person or entity acting as a group, would not beneficially own more than 9.99% of the outstanding Common Stock after
giving effect to such exercise, as such percentage ownership is determined in accordance with the terms of the Warrant (the “Beneficial
Ownership Limitation”), except that upon at least 61 days prior notice from the holder to the Issuer, the holder may waive
the Beneficial Ownership Limitation. The Beneficial Ownership Limitation does not limit the Reporting Persons at this time, as
none of the Reporting Persons may be deemed to beneficially own more than 9.99% after giving effect to the exercise of the Warrants.

The beneficial ownership for each of
the Reporting Persons includes the shares of Common Stock issuable upon exercise of the Warrants held by such Reporting Person
and is rounded down to the nearest full share of Common Stock.

As of the close of business on July
20, 2017 (i) BVF beneficially owned 2,443,720 shares of Common Stock, including 814,573 shares of Common Stock issuable upon the
exercise of certain Warrants, (ii) BVF2 beneficially owned 1,574,254 shares of Common Stock, including 524,751 shares of Common
Stock issuable upon the exercise of certain Warrants, and (iii) Trading Fund OS beneficially owned 437,841 shares of Common Stock,
including 145,947 shares of Common Stock issuable upon the exercise of certain Warrants.

Partners OS, as the general partner
of Trading Fund, OS may be deemed to beneficially own the 437,841 shares of Common Stock beneficially owned by Trading Fund OS,
including 145,947 shares of Common Stock issuable upon the exercise of certain Warrants.

Partners, as the general partner of
BVF, BVF2, the investment manager of Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the
5,250,000 shares of Common Stock beneficially owned in the aggregate by BVF, BVF2, Trading Fund OS, and certain Partners managed
accounts (the “Partners Managed Accounts”), including 794,184 shares of Common Stock held in the Partners Managed Accounts
(which includes 264,728 shares of Common Stock issuable upon the exercise of certain Warrants).

BVF Inc., as the general partner of
Partners, may be deemed to beneficially own the 5,250,000 shares of Common Stock beneficially owned by Partners.

Mr. Lampert, as a director and officer
of BVF Inc., may be deemed to beneficially own the 5,250,000 shares of Common Stock beneficially owned by BVF Inc.

The foregoing should not be construed
in and of itself as an admission by any Reporting Person as to beneficial ownership of any Common Stock owned by another Reporting
Person. Partners OS disclaims beneficial ownership of the Common Stock beneficially owned by Trading Fund OS. Each of Partners,
BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Common Stock beneficially owned by BVF, BVF2, Trading Fund OS, and
the Partners Managed Accounts, and the filing of this statement shall not be construed as an admission that any such person or
entity is the beneficial owner of any such securities.

The following percentages are based
on a denominator that is the sum of: (a) 73,656,606 shares of Common Stock outstanding as disclosed in the Issuer’s Prospectus
filed with the Securities and Exchange Commission on July 21, 2017 and (b) 1,750,000 shares of Common Stock issuable upon the exercise
of certain Warrants.

As of the close of business on July
20, 2017 (i) BVF beneficially owned approximately 3.2% of the outstanding Common Stock, including shares of Common Stock issuable
upon the exercise of certain Warrants (ii) BVF2 beneficially owned approximately 2.1% of the outstanding Common Stock, including
shares of Common Stock issuable upon the exercise of certain Warrants (iii) Trading Fund OS beneficially owned less than 1% of
the outstanding Common Stock including shares of Common Stock issuable upon the exercise of certain Warrants (iv) Partners OS may
be deemed to beneficially own less than 1% of the outstanding Common Stock, and (v) each of Partners, BVF Inc. and Mr. Lampert
may be deemed to beneficially own approximately 7.0% of the outstanding Common Stock (approximately 1.1% of which is held in the
Partners Managed Accounts, including shares of Common Stock issuable upon the exercise of certain Warrants).

See Cover Pages Items 5-9.

See Cover Pages Items 5-9.

See Cover Pages Items 5-9.

See Cover Pages Items 5-9.

Not Applicable.

Partners, BVF Inc. and Mr. Lampert
share voting and dispositive power over the shares of Common Stock beneficially owned by BVF, BVF2, Trading Fund OS, and the Partners
Managed Accounts.

Not Applicable.

See Exhibit 99.1.

Not Applicable.

By signing below each of
the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were not acquired and
are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were
not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

After reasonable inquiry
and to the best of his knowledge and belief, each of the undersigned certifies that the information set forth in this statement
is true, complete and correct.

Dated: July 28, 2017