SC 13D/A

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934
(Amendment No. 3 )*

Response Biomedical Corp.

(Name of Issuer)

Common Shares, without par value

(Title of Class of Securities)

76123L204

(CUSIP Number)

OrbiMed Advisors LLC
OrbiMed Advisors Limited
OrbiMed Asia GP, L.P.
OrbiMed Capital GP III LLC
Samuel D. Isaly
767 Third Avenue, 30th Floor
New York, NY 10017
Telephone: (212) 739-6400
Attn: Alexander M. Cooper

(Name, Address and Telephone Number of Person Authorized to
Receive Notices and Communications)

January 11, 2011

(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 §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. o

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7(b) 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).

CUSIP No. 76123L204 

1	NAMES OF REPORTING PERSONS OrbiMed Advisors LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a)   o
	(b)   o
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF (See Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
		7	SOLE VOTING POWER
NUMBER OF			0
SHARES		8	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			9,151,200 (See Items 3, 4 and 5)
EACH		9	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0
WITH		10	SHARED DISPOSITIVE POWER
			9,151,200 (See Items 3, 4 and 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	9,151,200 (See Items 3, 4 and 5)
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	23.6% (See Item 5)
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	IA

2

CUSIP No. 76123L204 

1	NAMES OF REPORTING PERSONS OrbiMed Advisors Limited
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a)   o
	(b)   o
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF (See Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Cayman Islands
		7	SOLE VOTING POWER
NUMBER OF			0
SHARES		8	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			5,376,300 (See Items 3, 4 and 5)
EACH		9	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0
WITH		10	SHARED DISPOSITIVE POWER
			5,376,300 (See Items 3, 4 and 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	5,376,300 (See Items 3, 4 and 5)
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	13.9% (See Item 5)
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO

3

CUSIP No. 76123L204 

1	NAMES OF REPORTING PERSONS OrbiMed Asia GP, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a)   o
	(b)   o
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF (See Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Cayman Islands
		7	SOLE VOTING POWER
NUMBER OF			0
SHARES		8	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			5,376,300 (See Items 3, 4 and 5)
EACH		9	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0
WITH		10	SHARED DISPOSITIVE POWER
			5,376,300 (See Items 3, 4 and 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	5,376,300 (See Items 3, 4 and 5)
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	13.9% (See Item 5)
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO

4

CUSIP No. 76123L204 

1	NAMES OF REPORTING PERSONS OrbiMed Capital GP III LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a)   o
	(b)   o
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF (See Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware
		7	SOLE VOTING POWER
NUMBER OF			0
SHARES		8	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			9,065,300 (See Items 3, 4 and 5)
EACH		9	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0
WITH		10	SHARED DISPOSITIVE POWER
			9,065,300 (See Items 3, 4 and 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	9,065,300 (See Items 3, 4 and 5)
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	23.4% (See Item 5)
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	OO

5

CUSIP No. 76123L204 

1	NAMES OF REPORTING PERSONS Samuel D. Isaly
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
	(a)   o
	(b)   o
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)
	AF (See Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e)
	o
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	United States
		7	SOLE VOTING POWER
NUMBER OF			0
SHARES		8	SHARED VOTING POWER
BENEFICIALLY
OWNED BY			9,151,200 (See Items 3, 4 and 5)
EACH		9	SOLE DISPOSITIVE POWER
REPORTING
PERSON			0
WITH		10	SHARED DISPOSITIVE POWER
			9,151,200 (See Items 3, 4 and 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	9,151,200 (See Items 3, 4 and 5)
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)
	o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	23.6% (See Item 5)
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
	IN

6

TABLE OF CONTENTS

Item 1. Security and Issuer

Item 3. Source and Amount of Funds or Other Consideration

Item 5. Interest in Securities of the Issuer

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

Item 7. Material to Be Filed as Exhibits

Signature

EX-99.E

7

Item 1. Security and Issuer

     This Amendment No. 3 (the “Amendment No. 3”) to Schedule 13D supplements and amends the Statement on Schedule 13D of OrbiMed Advisors LLC, OrbiMed Advisors Limited, OrbiMed Asia GP, L.P., OrbiMed Capital GP III LLC and Samuel D. Isaly originally filed on August 9, 2010, as amended by Amendment No. 1 to Schedule 13D filed on October 4, 2010 and Amendment No. 2 to Schedule 13D filed on October 22, 2010 (the “Schedule 13D”), relating to the common shares, without par value (the “Shares”), of Response Biomedical Corp., a corporation continued under the laws of the Province of British Columbia (the “Issuer”), having its principal executive offices located at 1781 — 75th Avenue W., Vancouver, BC, V6P 6P2 Canada.

     Each item below amends and supplements the information disclosed under the corresponding item of the Schedule 13D. Capitalized terms defined in the Schedule 13D are used herein with their defined meanings.

Item 3. Source and Amount of Funds or Other Consideration

     Item 3 of the Schedule 13D is hereby amended and supplemented by adding immediately after the last paragraph thereof the following:

     Effective October 25, 2010, Caduceus III was renamed OrbiMed Private Investments III, LP (“OPI III”) and Caduceus Asia was renamed OrbiMed Asia Partners, LP (“OAP”). Accordingly, all previous references in the Schedule 13D to Caduceus III and Caduceus Asia shall henceforth be deemed to refer to OPI III and OAP, respectively.

     Amendment No. 3 is being filed in connection with the acquisition by OPI III, OAP and OrbiMed Associates of Shares in open market transactions on November 17, 2010, November 29, 2010, December 3, 2010 and January 11, 2011 as described below in greater detail.

     Pursuant to its authority under the limited partnership agreement of OPI III, on November 17, 2010, November 29, 2010, December 3, 2010 and January 11, 2011, OrbiMed Capital, as general partner of OPI III, caused OPI III to purchase an aggregate of 271,000 Shares using OPI III’s working capital in the aggregate amount of approximately Cdn.$106,727.

     Pursuant to its authority under the limited partnership agreement of OAP, on November 17, 2010, November 29, 2010, December 3, 2010 and January 11, 2011, OrbiMed Asia caused OAP to purchase an aggregate of 127,600 Shares using OAP’s working capital in the aggregate amount of approximately Cdn.$49,309. Such authority is exercised through OrbiMed Limited as the sole general partner of OrbiMed Asia, which is the sole general partner of OAP.

     Pursuant to its authority under the limited partnership agreement of OrbiMed Associates, on November 17, 2010, November 29, 2010, December 3, 2010 and January 11, 2011, OrbiMed Advisors, as general partner of OrbiMed Associates, caused OrbiMed Associates to purchase an aggregate of 2,400 Shares using OrbiMed Associates’ working capital in the aggregate amount of approximately Cdn.$940.

Item 5. Interest in Securities of the Issuer

     Item 5(a) and 5(b) of the Schedule 13D is hereby amended and restated in its entirety by the following:

     (a) — (b) The following disclosure assumes that there are 38,800,755 Shares outstanding, which number is based upon information contained in the most recent available filing by the Issuer with the SEC (a Form 6-K file on November 9, 2010).

     The 5,376,300 Shares held by OAP constitute approximately 13.9% of the issued and outstanding Shares. OrbiMed Asia is the sole general partner of OAP pursuant to the terms of the limited partnership agreement of OAP and OrbiMed Limited is the sole general partner of OrbiMed Asia pursuant to the terms of the limited partnership agreement of OrbiMed Asia. As a result, OrbiMed Asia has the power to direct the vote and to direct the disposition of the Shares held by OAP described in Item 3 and such power is exercised through OrbiMed Limited. OrbiMed Limited exercises this investment power through an investment committee (the “Committee”) comprised of Isaly, Carl L. Gordon, Nancy T. Chang, Jonathan J. Wang and Sunny Sharma, each of whom disclaims beneficial ownership of the Shares held by OAP, except to the extent of their pecuniary interest therein, if any. As a result, OrbiMed Asia and OrbiMed

8

Limited may be deemed directly or indirectly, including by reason of their mutual affiliation, to be the beneficial owners of the Shares held by OAP and to share power to direct the vote and the disposition of the Shares held by OAP.

     As of the date of this filing, OrbiMed Capital, OrbiMed Advisors and Isaly may be deemed directly or indirectly, including by reason of their mutual affiliation, to be the beneficial owners of the Shares held by OPI III described in Item 3. The 9,065,300 Shares held by OPI III constitute approximately 23.4% of the issued and outstanding Shares. Isaly owns a controlling interest in OrbiMed Advisors pursuant to the terms of its limited liability company agreement. OrbiMed Advisors is the sole managing member of OrbiMed Capital and OrbiMed Capital is the sole general partner of OPI III. As a result, Isaly, OrbiMed Advisors and OrbiMed Capital share power to direct the vote and to direct the disposition of the Shares held by OPI III described in Item 3.

     As of the date of this filing, OrbiMed Advisors and Isaly may be deemed directly or indirectly, including by reason of their mutual affiliation, to be the beneficial owners of the Shares held by OrbiMed Associates described in Item 3. The 85,900 Shares held by OrbiMed Associates constitute approximately 0.2% of the issued and outstanding Shares. Isaly owns a controlling interest in OrbiMed Advisors pursuant to the terms of its limited liability company agreement. As a result, Isaly and OrbiMed Advisors share power to direct the vote and to direct the disposition of the Shares held by OrbiMed Associates described in Item 3.

     Item 5(c) of the Schedule 13D is hereby amended and supplemented by adding immediately at the end of such section the following:

     The following table sets forth all transactions with respect to the Shares effected by the Reporting Persons since October 22, 2010 (the date Amendment No. 2 to Schedule 13D was originally filed). All of the following transactions were effected in the open market.

		Number of
Date of		Shares		Price per
Transaction	Purchasing Entity	Acquired		Share(1)
November 17, 2010	OPI III		24,800	Cdn.$0.41
November 17, 2010	OAP		11,500	Cdn.$0.41
November 17, 2010	OrbiMed Associates		200	Cdn.$0.41
November 29, 2010	OPI III		47,300	Cdn.$0.42
November 29, 2010	OAP		21,800	Cdn.$0.42
November 29, 2010	OrbiMed Associates		400	Cdn.$0.42
December 3, 2010	OPI III		75,400	Cdn.$0.42
December 3, 2010	OAP		19,000	Cdn.$0.42
December 3, 2010	OrbiMed Associates		600	Cdn.$0.42
January 11, 2011	OPI III		123,500	Cdn.$0.36
January 11, 2011	OAP		75,300	Cdn.$0.36
January 11, 2011	OrbiMed Associates		1,200	Cdn.$0.36

(1) Represents weighted average price per share paid on such date. The Reporting Persons undertake to provide upon request of the staff of the SEC full information regarding the number of Shares purchased at each separate price used to calculate the average price.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

     Item 6 of the Schedule 13D is hereby amended and restated in its entirety by the following:

     In addition to the relationships between the Reporting Persons described in Item 5, OrbiMed Capital is the sole general partner of OPI III, pursuant to the terms of the limited partnership agreement of OPI III. Pursuant to this agreement and relationship, OrbiMed Capital has discretionary investment management authority with respect to the assets of OPI III. Such authority includes the power to vote and otherwise dispose of securities purchased by OPI III. The number of outstanding Shares of the Issuer attributable to OPI III is 9,065,300. OrbiMed Capital, pursuant to its authority under the limited partnership agreement of OPI III, may be considered to hold indirectly 9,065,300 Shares.

     OrbiMed Advisors is the sole managing member of OrbiMed Capital, pursuant to the terms of the limited liability company agreement of OrbiMed Capital. Pursuant to these agreements and relationships, OrbiMed Advisors and OrbiMed Capital have

9

discretionary investment management authority with respect to the assets of OPI III. Such authority includes the power of OrbiMed Capital to vote and otherwise dispose of securities purchased by OPI III. The number of outstanding Shares attributable to OPI III is 9,065,300 Shares. OrbiMed Advisors is also the general partner of OrbiMed Associates, pursuant to the terms of the limited partnership agreement of OrbiMed Associates. Pursuant to this agreement and relationship, OrbiMed Advisors has discretionary investment management authority with respect to the assets of OrbiMed Associates. Such authority includes the power to vote and otherwise dispose of securities purchased by OrbiMed Associates. The number of outstanding Shares of Issuer attributable to OrbiMed Associates is 85,900. OrbiMed Advisors, pursuant to its authority under its limited partnership agreement with OrbiMed Associates, may be considered to hold indirectly 85,900 Shares.

     OrbiMed Asia is the sole general partner of OAP pursuant to the terms of the limited partnership agreement of OAP. OrbiMed Limited is the sole general partner of OrbiMed Asia pursuant to the terms of the limited partnership agreement of OrbiMed Asia. OrbiMed Limited established the Committee by written resolutions adopted on July 28, 2010. Pursuant to these agreements, resolutions and relationships, OrbiMed Asia has discretionary investment management authority with respect to the assets of OAP and such discretionary investment management authority is exercised through OrbiMed Limited by action of the Committee. Such authority includes the power to vote and otherwise dispose of securities purchased by OAP. The number of outstanding Shares of the Issuer attributable to OAP is 5,376,300. OrbiMed Asia, as the general partner of OAP, may be considered to hold indirectly 5,376,300 Shares, and OrbiMed Limited, as the general partner of OrbiMed Asia, may be considered to hold indirectly 5,376,300 Shares.

     As noted in Item 4 of the Schedule 13D, Peter Thompson, M.D. and Jonathan J. Wang (individuals designated by OPI III to sit on the Issuer’s Board), are members of the Issuer’s Board and, accordingly, the Reporting Persons may have the ability to affect and influence control of the Issuer.

     Other than the agreements and the relationships mentioned above, to the best knowledge of the Reporting Persons, there are no contracts, arrangements, understandings or relationships (legal or otherwise) among the persons named in Item 2 and between such persons and any persons with respect to any securities of the Issuer, including, but not limited to, transfer or voting of any of the Shares, finder’s fees, joint ventures, loan or option arrangements, puts or calls, guarantees of profits, division of profits or loss, or the giving of withholding of proxies.

Item 7. Material to Be Filed as Exhibits

     Item 7 of the Schedule 13D is hereby amended and supplemented by adding at the end thereto the following:

Exhibit	Title
E	Joint Filing Agreement, dated as of January 13, 2011, by and among OrbiMed Advisors LLC, OrbiMed Advisors Limited, OrbiMed Asia GP, L.P., OrbiMed Capital GP III LLC and Samuel D. Isaly.

10

Signature

     After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: January 13, 2011	ORBIMED ADVISORS LLC a Delaware Limited Liability Company
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Managing Member
	ORBIMED ADVISORS LIMITED a Cayman Islands corporation
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Director
	ORBIMED ASIA GP, L.P. a Cayman Islands limited partnership
	By:	ORBIMED ADVISORS LIMITED, its general partner
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Director
	ORBIMED CAPITAL GP III LLC a Delaware limited liability company
	By:	ORBIMED ADVISORS LLC, its managing member
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Managing Member
	SAMUEL D. ISALY
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly

11

EX-99.E

Exhibit E

JOINT FILING AGREEMENT

     The undersigned hereby agree that the Statement on Schedule 13D, dated August 9, 2010, as amended by Amendment No. 1 to Schedule 13D originally filed on October 4, 2010 and Amendment No. 2 to Schedule 13D originally filed on October 22, 2010 (the “Schedule 13D”), and the Amendment No. 3 to the Schedule 13D, dated January 13, 2011 (the “Amendment No. 3”), (including any subsequent amendments, restatements, supplements, and/or exhibits thereto) with respect to the common shares, without par value, of Response Biomedical Corp. was and is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities and Exchange Act of 1934, as amended, and that this Agreement shall be included as an Exhibit to this Amendment No. 3. Each of the undersigned agrees to be responsible for the timely filing of the Amendment No. 3, and for the completeness and accuracy of the information concerning itself contained therein. This Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.

     IN WITNESS WHEREOF, the undersigned have executed this Agreement as of the 13th day of January, 2011.

Dated: January 13, 2011	ORBIMED ADVISORS LLC a Delaware Limited Liability Company
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Managing Member
	ORBIMED ADVISORS LIMITED a Cayman Islands corporation
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Director
	ORBIMED ASIA GP, L.P. a Cayman Islands limited partnership
	By:	ORBIMED ADVISORS LIMITED, its general partner
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Director
	ORBIMED CAPITAL GP III LLC a Delaware limited liability company
	By:	ORBIMED ADVISORS LLC, its managing member
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly
		Managing Member
	SAMUEL D. ISALY
	By:	/s/ Samuel D. Isaly
		Samuel D. Isaly