UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 orOR 15(d) of ~~the~~

The Securities Exchange Act of 1934

Date of Report: ~~October~~(Date 5,of ~~2004~~earliest ~~(October~~event ~~4, 2004~~reported)

~~(Date~~October of18, ~~Earliest~~2004 ~~Event Reported)~~

ACLARA BIOSCIENCES, INC.

(Exact ~~Name~~name of ~~Registrant~~registrant as ~~Specified~~specified in ~~Its~~its ~~Charter~~charter)

Delaware	~~Commission File:~~0-29975	94-3222727
(State or Other Jurisdiction of Incorporation or Organization)	0-29975	(I.R.S. Employer Identification No.)
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)

1288 Pear Avenue


1288 Pear Avenue, Mountain View, California		94043
(Address of principal executive offices)		(Zip Code)

~~Mountain~~Registrant’s ~~View~~telephone number, ~~California~~including ~~94043~~area code

(Address of Principal Executive Offices)

(650) 210-1200

Not Applicable (~~Registrant’s~~Former ~~Telephone~~name ~~Number~~or former address, ~~Including~~if ~~Area~~changed ~~Code)~~since last report)

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 18.01. ~~ENTRY~~OTHER ~~INTO~~EVENTS ~~A MATERIAL DEFINITIVE AGREEMENT.~~

On October 418, 2004, ACLARA BioSciences, Inc. and Mellon Investor Services LLC, aacting ~~Delaware~~as ~~corporation~~the rights agent, executed the Third Amendment to the Rights Agreement (the “~~Registrant”~~Third ~~or “ACLARA~~Amendment”), ~~entered~~amending ~~into~~the anRights ~~agreement~~Agreement, ~~with~~dated ~~GlaxoSmithKline~~as ~~(“GSK”)~~of March 16, 2001, as amended by the Amendment to ~~evaluate~~the ~~ACLARA’s~~Rights ~~proprietary~~Agreement, ~~eTag™~~dated ~~technology~~as ~~assays~~of ~~for~~May ~~GSK’s~~28, ~~potential~~2004 ~~use~~and inby ~~patient~~the ~~selection~~Second ~~for~~Amendment ~~certain~~to ofthe ~~GSK’s~~Rights ~~targeted~~Agreement, ~~cancer~~dated ~~therapies~~as of June 11, 2004. The Third Amendment is attached hereto as Exhibit 4.3 and is incorporated into this report as if fully set forth herein.

~~Under~~On ~~the~~October ~~agreement~~18, ~~GSK~~2004, ~~will~~ACLARA ~~provide~~BioSciences, toInc., ~~ACLARA biological~~Perry ~~samples~~Partners, ~~treated~~L.P., ~~with~~Perry aPartners ~~drug~~International, Inc., and ~~ACLARA~~Auda ~~will~~Classics ~~test~~plc ~~the~~executed ~~samples~~a ~~with~~Standstill Agreement ~~its~~(the ~~eTag~~“Standstill ~~assays~~Agreement”). ~~ACLARA~~The ~~and~~Standstill ~~GSK~~Agreement ~~will~~is ~~then~~attached ~~correlate~~hereto ~~the parameters measured~~ as ~~biomarkers~~Exhibit ~~with~~4.4 ~~response~~and tois ~~the~~incorporated ~~drug.~~into ~~GSK~~this ~~will~~report ~~provide~~as ~~funding~~if tofully ~~ACLARA~~set ~~for~~forth ~~the study~~herein.

~~SIGNATURE~~ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS


Number		Exhibit
4.3		Third Amendment to the Rights Agreement, dated as of October 18, 2004, by and between ACLARA BioSciences, Inc., a Delaware corporation, and Mellon Investor Services LLC, a New Jersey limited liability company.

4.4		Standstill Agreement, dated as of October 18, 2004, by and between ACLARA BioSciences, Inc., a Delaware corporation, Perry Partners, L.P., a Delaware limited partnership, Perry Partners International, Inc., a British Virgin Islands corporation, and Auda Classics plc.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

~~Dated~~ACLARA BIOSCIENCES, INC. By: ~~October~~/s/ 5,Alfred ~~2004~~ G. Merriweather Alfred G. Merriweather Chief Financial Officer

~~ACLARA BIOSCIENCES, INC. By~~Dated: ~~/s/~~October ~~Alfred G. Merriweather Alfred G. Merriweather Vice President~~19, ~~Finance and Chief Financial Officer~~2004

EXHIBIT INDEX


Exhibit No.		Description
4.3		Third Amendment to the Rights Agreement, dated as of October 18, 2004, by and between ACLARA BioSciences, Inc., a Delaware corporation, and Mellon Investor Services LLC, a New Jersey limited liability company.

4.4		Standstill Agreement, dated as of October 18, 2004, by and between ACLARA BioSciences, Inc., a Delaware corporation, Perry Partners, L.P., a Delaware limited partnership, Perry Partners International, Inc., a British Virgin Islands corporation, and Auda Classics plc.

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