SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* PROSPECT VENTURE PARTNERS II LP (Last) (First) (Middle) 435 TASSO STREET SUITE 200 (Street) PALO ALTO CA 94301 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Trubion Pharmaceuticals, Inc [ TRBN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 10/17/2006
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/17/2006		C		1,795,112	A	(1)	1,795,112	I	By Prospect Venture Partners II, L.P.(2)
Common Stock	10/17/2006		C		27,338	A	(1)	27,338	I	By Prospect Associates II, L.P.(3)
Common Stock	10/17/2006		P		34,653	A	$13	1,829,765	I	By Prospect Venture Partners II, L.P.(2)
Common Stock	10/17/2006		P		528	A	$13	27,866	I	By Prospect Associates II, L.P.(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series B Convertible Preferred	(4)	10/17/2006		C			1,795,112	10/17/2006(4)	10/17/2006(5)	Common Stock	1,795,112	$0(5)	1,795,112	I	By Prospect Venture Partners II, L.P.(2)
Series B Convertible Preferred	(4)	10/17/2006		C			27,338	10/17/2006(4)	10/17/2006(5)	Common Stock	27,338	$0(5)	27,338	I	By Prospect Associates II, L.P.(3)

1. Name and Address of Reporting Person* PROSPECT VENTURE PARTNERS II LP (Last) (First) (Middle) 435 TASSO STREET SUITE 200 (Street) PALO ALTO CA 94301 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* PROSPECT MANAGEMENT CO II LLC (Last) (First) (Middle) 435 TASSO STREET SUITE 200 (Street) PALO ALTO CA 94301 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* PROSPECT ASSOCIATES II L P (Last) (First) (Middle) 435 TASSO STREET SUITE 200 (Street) PALO ALTO CA 94301 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* TANANBAUM JAMES B (Last) (First) (Middle) 435 TASSO STREET SUITE 200 (Street) PALO ALTO CA 94301 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* HIRSCH RUSSELL C (Last) (First) (Middle) 435 TASSO STREET SUITE 200 (Street) PALO ALTO CA 94301 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* BARKAS ALEXANDER E (Last) (First) (Middle) 435 TASSO STREET SUITE 200 (Street) PALO ALTO CA 94301 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Each share of Series B Convertible Preferred Stock converted automatically into shares of Common Stock on a 1-for-1 basis immediately prior to the closing of the Issuer's initial public offering and had no expiration date.

2. The shares are owned by Prospect Venture Partners II, L.P. ("PVP II"). Prospect Management Co. II, L.L.C. ("PMC II") serves as the sole general partner of PVP II. James B. Tananbaum, M.D., Alexander E. Barkas, Ph.D., David Schnell, M.D., and Russell C. Hirsch, M.D., Ph.D. are the Managing Directors of PMC II. Each reporting person disclaims beneficial ownership of the shares reported herein, except to the extent of its pecuniary interest.

3. The shares are owned by Prospect Associates II, L.P. ("PA II"). PMC II serves as the sole general partner of PA II. James B. Tananbaum, M.D., Alexander E. Barkas, Ph.D., David Schnell, M.D., and Russell C. Hirsch, M.D., Ph.D. are the Managing Directors of PMC II. Each reporting person disclaims beneficial ownership of the shares reported herein, except to the extent of its pecuniary interest.

4. These securities were automatically converted into Common Stock on a 1-for-1 basis upon the closing of the Issuer's initial public offering.

5. Not applicable.

	/s/ Dave Markland, Power of Attorney for Prospect Management Co. II, L.L.C.	10/19/2006
	/s/ Dave Markland, Power of Attorney for Prospect Venture Partners II, L.P.	10/19/2006
	/s/ Dave Markland, Power of Attorney for Prospect Assocates II, L.P.	10/19/2006
	/s/ Dave Markland, Power of Attorney for James B Tananbaum	10/19/2006
	/s/ Dave Markland, Power of Attorney for Russell C Hirsch	10/19/2006
	/s/ Dave Markland, Power of Attorney for Alexander E Barkas	10/19/2006
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.