UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

o

Rule 13d-1(b)

x

Rule 13d-1(c)

o

Rule 13d-1(d)

CUSIP No. 157085101

(1)

Names of Reporting Persons
Capital Ventures International

(2)

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

o

(3)

SEC Use Only

(4)

Citizenship or Place of Organization
Cayman Islands

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With:

(5)

Sole Voting Power
0

(6)

Shared Voting Power **
2,000,000 Shares of Common Stock

(7)

Sole Dispositive Power
0

(8)

Shared Dispositive Power **
2,000,000 Shares of Common Stock

(9)

Aggregate Amount Beneficially Owned by Each Reporting Person
2,000,000 Shares of Common Stock

(10)

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

(11)

Percent of Class Represented by Amount in Row (9)
5.2%

(12)

Type of Reporting Person (See Instructions)
CO

CUSIP No. 157085101

(1)

Names of Reporting Persons
Heights Capital Management, Inc.

(2)

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

o

(3)

SEC Use Only

(4)

Citizenship or Place of Organization
Delaware

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With:

(5)

Sole Voting Power
0

(6)

Shared Voting Power **
2,000,000 Shares of Common Stock

(7)

Sole Dispositive Power
0

(8)

Shared Dispositive Power **
2,000,000 Shares of Common Stock

(9)

Aggregate Amount Beneficially Owned by Each Reporting Person
2,000,000 Shares of Common Stock

(10)

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

(11)

Percent of Class Represented by Amount in Row (9)
5.2%

(12)

Type of Reporting Person (See Instructions)
CO

CUSIP No. 157085101

Item 1.

(a)

Name of Issuer
Cerus Corporation, a Delaware corporation (the “Company”).

(b)

Address of Issuer’s Principal Executive Offices
2411 Stanwell Drive

Concord, CA  94520

Item 2

(a).

Name of Person Filing

This statement is filed by the entities listed below, who are collectively referred to herein as “Reporting Persons,” with respect to the shares of Common Stock of the Company, $0.001 par value per share (the “Shares”).

(i)            Capital Ventures International

(ii)           Heights Capital Management, Inc.

Item 2

(b).

Address of Principal Business Office or, if none, Residence

The address of the principal business office of Capital Ventures International is:

One Capitol Place

P.O Box 1787 GT

Grand Cayman, Cayman Islands

British West Indies

The address of the principal business office of Heights Capital Management, Inc. is:

101 California Street, Suite 3250

San Francisco, California 94111

Item 2

(c).

Citizenship

Citizenship is set forth in Row 4 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.

Item 2

(d)

Title of Class of Securities

Common Stock, $0.001 par value per share

Item 2

(e)

CUSIP Number

157085101

Item 3.

If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

o

Broker or dealer registered under Section 15 of the Act (15 U.S.C. 78o);

(b)

o

Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c);

(c)

o

Insurance company as defined in Section 3(a)(19) of the Act (15 U.S.C. 78c);

(d)

o

Investment company registered under Section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);

(e)

o

An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);

(f)

o

An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);

CUSIP No. 157085101

(g)

o

A parent holding company or control person in accordance with §240.13d-1(b)(1)(ii)(G);

(h)

o

A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

o

A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

o

A non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J);

(k)

o

Group, in accordance with Rule 13d-1(b)(1)(ii)(K).

If filing as a non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J), please specify the type of institution:

Item 4.

Ownership

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

The information required by Items 4(a) – (c) is set forth in Rows 5 – 11 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person. The Company’s Prospectus Supplement (to Prospectus dated December 17, 2008, Registration Nos. 333-154842 and 333-161214), filed on August 20, 2009 indicates there are 38,649,123 Shares outstanding as of the completion of the offering of the Shares to the Reporting Persons.  In calculating the number and percentage of Shares held by the Reporting Persons, we did not include warrants to purchase 800,000 Shares, which are not exercisable to the extent that the total number of Shares then beneficially owned by the Reporting Person and its Affiliates and any other Persons whose beneficial ownership of Shares would be aggregated with the Reporting Person for purposes of Section 13(d) of the Exchange Act, exceeds 4.99%.

Heights Capital Management, Inc., which serves as the investment manager to Capital Ventures International, may be deemed to be the beneficial owner of all Shares owned by Capital Ventures International. Each of the Reporting Persons hereby disclaims any beneficial ownership of any such Shares, except for their pecuniary interest therein.

Item 5.

Ownership of Five Percent or Less of a Class

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following:   o

Item 6.

Ownership of More than Five Percent on Behalf of Another Person

Not applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company

Not applicable.

Item 8.

Identification and Classification of Members of the Group

Not applicable

CUSIP No. 157085101

Item 9.

Notice of Dissolution of Group

Not applicable.

Item 10.

Certification

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.

Exhibits:

Exhibit I: Joint Filing Agreement, dated as of August 28, 2009, by and among Capital Ventures International and Heights Capital Management, Inc.

CUSIP No. 157085101

CAPITAL VENTURES INTERNATIONAL

HEIGHTS CAPITAL MANAGEMENT, INC.

By: Heights Capital Management, Inc. pursuant to a Limited

By:

/s/ Todd Silverberg

Power of Attorney

Name:

Todd Silverberg

Title

Secretary

By:

/s/ Todd Silverberg

Name:

Todd Silverberg

Title

Secretary

CUSIP No. 157085101

CAPITAL VENTURES INTERNATIONAL

HEIGHTS CAPITAL MANAGEMENT, INC.

By: Heights Capital Management, Inc. pursuant to a Limited

By:

/s/ Todd Silverberg

Power of Attorney

Name:

Todd Silverberg

Title

Secretary

By:

/s/ Todd Silverberg

Name:

Todd Silverberg

Title

Secretary