Filing Details

 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

 

Spero Therapeutics, Inc.

(Name of Issuer)

Common Stock, $0.001 par value

(Title of Class of Securities)

84833T103

(CUSIP Number)

November 2, 2017

(Date of Event Which Requires Filing of this Statement)

 

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

☐

Rule 13d-1(b)

☒

Rule 13d-1(c)

☐

Rule 13d-1(d)

 

 

1              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).

 

1

NAME OF REPORTING PERSON

Biotechnology Value Fund, L.P.

2

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

3

SEC USE ONLY

4

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

5

SOLE VOTING POWER

SHARES

BENEFICIALLY

0 shares

OWNED BY

6

SHARED VOTING POWER

EACH

REPORTING

510,846

PERSON WITH

7

SOLE DISPOSITIVE POWER

0 shares

8

SHARED DISPOSITIVE POWER

510,846

9

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

510,846

10

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

11

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

3.7%

12

TYPE OF REPORTING PERSON

PN

  

1

NAME OF REPORTING PERSON

Biotechnology Value Fund II, L.P.

2

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

3

SEC USE ONLY

4

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

5

SOLE VOTING POWER

SHARES

BENEFICIALLY

0 shares

OWNED BY

6

SHARED VOTING POWER

EACH

REPORTING

326,647

PERSON WITH

7

SOLE DISPOSITIVE POWER

0 shares

8

SHARED DISPOSITIVE POWER

326,647

9

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

326,647

10

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

11

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

2.4%

12

TYPE OF REPORTING PERSON

PN

  

 

1

NAME OF REPORTING PERSON

Biotechnology Value Trading Fund OS LP

2

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

3

SEC USE ONLY

4

CITIZENSHIP OR PLACE OF ORGANIZATION

Cayman Islands

NUMBER OF

5

SOLE VOTING POWER

SHARES

BENEFICIALLY

0 shares

OWNED BY

6

SHARED VOTING POWER

EACH

REPORTING

87,695

PERSON WITH

7

SOLE DISPOSITIVE POWER

0 shares

8

SHARED DISPOSITIVE POWER

87,695

9

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

87,695

10

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

11

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

Less than 1%

12

TYPE OF REPORTING PERSON

PN

  

 

1

NAME OF REPORTING PERSON

BVF Partners OS Ltd.

2

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

3

SEC USE ONLY

4

CITIZENSHIP OR PLACE OF ORGANIZATION

Cayman Islands

NUMBER OF

5

SOLE VOTING POWER

SHARES

BENEFICIALLY

0 shares

OWNED BY

6

SHARED VOTING POWER

EACH

REPORTING

87,695

PERSON WITH

7

SOLE DISPOSITIVE POWER

0 shares

8

SHARED DISPOSITIVE POWER

87,695

9

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

87,695

10

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

11

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

Less than 1%

12

TYPE OF REPORTING PERSON

CO

  

 

1

NAME OF REPORTING PERSON

BVF Partners L.P.

2

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

3

SEC USE ONLY

4

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

5

SOLE VOTING POWER

SHARES

BENEFICIALLY

0 shares

OWNED BY

6

SHARED VOTING POWER

EACH

REPORTING

1,029,185

PERSON WITH

7

SOLE DISPOSITIVE POWER

0 shares

8

SHARED DISPOSITIVE POWER

1,029,185

9

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,029,185

10

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

11

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

7.4%

12

TYPE OF REPORTING PERSON

PN, IA

  

 

1

NAME OF REPORTING PERSON

BVF Inc.

2

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

3

SEC USE ONLY

4

CITIZENSHIP OR PLACE OF ORGANIZATION

Delaware

NUMBER OF

5

SOLE VOTING POWER

SHARES

BENEFICIALLY

0 shares

OWNED BY

6

SHARED VOTING POWER

EACH

REPORTING

1,029,185

PERSON WITH

7

SOLE DISPOSITIVE POWER

0 shares

8

SHARED DISPOSITIVE POWER

1,029,185

9

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,029,185

10

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

11

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

7.4%

12

TYPE OF REPORTING PERSON

CO

  

 

1

NAME OF REPORTING PERSON

Mark N. Lampert

2

CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

(a) ☒

(b) ☐

3

SEC USE ONLY

4

CITIZENSHIP OR PLACE OF ORGANIZATION

United States

NUMBER OF

5

SOLE VOTING POWER

SHARES

BENEFICIALLY

0 shares

OWNED BY

6

SHARED VOTING POWER

EACH

REPORTING

1,029,185

PERSON WITH

7

SOLE DISPOSITIVE POWER

0 shares

8

SHARED DISPOSITIVE POWER

1,029,185

9

AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

1,029,185

10

CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES

☐

11

PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

7.4%

12

TYPE OF REPORTING PERSON

IN

  

Item 1(a).

Name of Issuer:

 

Spero Therapeutics, Inc., a Delaware corporation (the “Issuer”).

 

Item 1(b).

Address of Issuer's Principal Executive Offices:

 

675 Massachusetts Avenue, 14th Floor

Cambridge, Massachusetts 02139

 

Item 2(a).

Name of Person Filing

Item 2(b).

Address of Principal Business Office or, if None, Residence

Item 2(c).

Citizenship

 

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.”

 

Item 2(d).

Title of Class of Securities:

 

Common Stock, $0.001 par value (the “Common Stock”)

 

Item 2(e).

CUSIP Number:

 

84833T103

 

Item 3.

If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

 

	/x/	Not applicable.
(a)	/ /	Broker or dealer registered under Section 15 of the Exchange Act.
(b)	/ /	Bank as defined in Section 3(a)(6) of the Exchange Act.
(c)	/ /	Insurance company as defined in Section 3(a)(19) of the Exchange Act.
(d)	/ /	Investment company registered under Section 8 of the Investment Company Act.
(e)	/ /	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E).
(f)	/ /	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F).
(g)	/ /	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G).
(h)	/ /	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act.
(i)	/ /	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act.
(j)	/ /	Group, in accordance with Rule 13d-1(b)(1)(ii)(J).
(k)	/ /	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with Rule 240.13d-1(b)(1)(ii)(J), please specify the type of institution: ____

 

Item 4.

Ownership

 

(a)

Amount beneficially owned:

 

As of the close of business on November 9, 2017 (i) BVF beneficially owned 510,846 shares of Common Stock, (ii) BVF2 beneficially owned 326,647 shares of Common Stock, and (iii) Trading Fund OS beneficially owned 87,695 shares of Common Stock.

 

Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 87,695 shares of Common Stock beneficially owned by Trading Fund OS.

 

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 1,029,185 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 103,997 shares of Common Stock held in the Partners Managed Accounts.

 

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 1,029,185 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 1,029,185 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 shares of Common Stock owned by another Reporting Person. Partners OS disclaims beneficial ownership of the shares of Common Stock beneficially owned by Trading Fund OS. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the shares of 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.

 

(b)

Percent of class:

 

The following percentages are based on 13,897,684 shares of Common Stock outstanding as disclosed in the Issuer’s prospectus filed with the Securities and Exchange Commission on November 2, 2017.

 

As of the close of business on November 9, 2017 (i) BVF beneficially owned approximately 3.7% of the outstanding shares of Common Stock, (ii) BVF2 beneficially owned approximately 2.4% of the outstanding shares of Common Stock, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding shares of Common Stock (iv) Partners OS may be deemed to beneficially own less than 1% of the outstanding shares of Common Stock, and (v) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 7.4% of the outstanding shares of Common Stock (less than 1% of which is held in the Partners Managed Accounts).

 

(c)

Number of shares as to which such person has:

 

(i)

Sole power to vote or to direct the vote

 

See Cover Pages Items 5-9.

 

(ii)

Shared power to vote or to direct the vote

 

See Cover Pages Items 5-9.

 

(iii)

Sole power to dispose or to direct the disposition of

 

See Cover Pages Items 5-9.

 

(iv)

Shared power to dispose or to direct the disposition of

 

See Cover Pages Items 5-9.

 

Item 5.

Ownership of Five Percent or Less of a Class.

 

Not Applicable.

 

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

 

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.

 

Item 7.

Identification and Classification of the Subsidiary That Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

 

Not Applicable.

 

Item 8.

Identification and Classification of Members of the Group.

 

See Exhibit 99.1.

 

Item 9.

Notice of Dissolution of Group.

 

Not Applicable.

 

Item 10.

Certifications.

 

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: November 9, 2017

 

BIOTECHNOLOGY VALUE FUND, L.P.			BVF INC.
By:	BVF Partners L.P., its general partner			/s/ Mark N. Lampert
By:	BVF Inc., its general partner		By:	Mark N. Lampert
				President
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President		/s/ Mark N. Lampert
			MARK N. LAMPERT
BIOTECHNOLOGY VALUE FUND II, L.P.
By:	BVF Partners L.P., its general partner
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President
BVF PARTNERS L.P.
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President

 

BVF PARTNERS OS LTD.
By:	BVF Partners L.P., its sole member
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President
Biotechnology Value Trading Fund OS LP
By:	BVF Partners L.P., its investment manager
By:	BVF Inc., its general partner
By:	/s/ Mark N. Lampert
	Mark N. Lampert
	President