This second amendment to the Custom Instrument Development and Commercialization Agreement (the "Second Amendment"), is entered into as of October 26, 2001 (the "Second Amendment Effective Date"), by and between The R. W. Johnson Pharmaceutical Research Institute, a division of Ortho-McNeil Pharmaceutical, Inc., a Delaware corporation having a business address at 920U. S. Route 202, Raritan, New Jersey (hereinafter "PRI"), and ACLARA Biosciences, Inc., a Delaware corporation having a principal place of business at 1288 Pear Avenue, Mountain View California 94043-1432 (hereinafter "ACLARA"). PRI and ACLARA are referred to in this Second Amendment individually or collectively as Party or Parties, as the case may be, and all references to PRI and ACLARA shall include their Affiliates, as defined in the Custom Instrument Development and Commercialization Agreement.

WHEREAS, PRI, ACLARA, and Applied Bio systems Group, a business of Applera Corporation and now doing business under the name Applied Bio systems, Inc., and having a principal place of business at 850 Lincoln Center Drive, Foster City, California 94404 (hereinafter "ABG") previously entered into a Custom Instrument Development and Commercialization Agreement (the "1998 Agreement") effective as of October 1, 1998 for the period October 1, 1998 through March 31, 2001;

WHEREAS, PRI, ACLARA entered into the 1998 Agreement, pursuant to which they pursued the goal of designing, developing and producing prototype high-throughput chip reading devices incorporating microfluidic technology;

WHEREAS, PRI, ACLARA, and ABG previously entered into a first amendment to the 1998 Agreement (the "First Amendment") in which the 1998 Agreement was as amended by the parties thereto as of October 1, 2001 (the "First Amendment Signing Date") and was retroactively effective as of September 30, 2000 (the "First Amendment Effective Date");

WHEREAS, ABG has withdrawn from further participation in collaborative research under the 1998 Agreement pursuant to the First Amendment as of the First Amendment Effective Date;

WHEREAS, as of the First Amendment Effective Date, the Goal had not been achieved;

WHEREAS, although the Goal was not achieved, collaborative research under the 1998 Agreement has produced significant experimental results that provide insight into the technology required to achieve such Goal, as well as the feasibility of implementing identified technical solutions;

WHEREAS, ACLARA has developed proprietary eTag and [*] technologies for [*] instrumentation, or chip based systems incorporating microfluidic technology, respectively;

WHEREAS, PRI and ACLARA desire to continue some aspects of the collaborative research under the 1998 Agreement beyond and after the First Amendment Effective Date, and desire to restate the Goal and other aspects of the 1998 Agreement in order to continue the collaborative research initiated under the PRI Agreement. PRI is also interested in obtaining access to the eTag and [*] technologies;

WHEREAS, this Second Amendment shall not replace or supersede the First Amendment;

WHEREAS, PRI and ACLARA desire to amend the 1998 Agreement and incorporate this Second Amendment therein;

NOW, THEREFORE, PRI and ACLARA agree as follows:

1. Section 1.2 is deleted in its entirety.

2. Section 1.6 is deleted in its entirety.

3. Section 1.7 is deleted in its entirety.

4. Section 1.8 is deleted in its entirety.

5. Section 1.14 shall be deleted in its entirety and replaced with the following:

1.14 "High Throughput Screening" or "HTS" shall mean methods utilizing microfluidic Chips, [*] ACLAmate or [*] instruments which involve: (i) [*] of candidate compounds are contacted with the target, the result of which contact [*], said activity being determined based upon subsequent analysis [*] (ii) [*] of candidate compounds are contacted with the target, the result of which contact [*] being determined based upon subsequent analysis [*] eTag Technology, and [*].

6. Section 1.15 shall be deleted in its entirety and replaced with the following:

1.15 "HTS Chip Device" shall mean a microfluidic high throughput screening instrument which may be developed as part of the Project, which may consist of one or more components and peripherals, capable of performing approximately one hundred thousand (100,000) individual assays per instrument per [*] day, or such other number as the Parties may agree in writing from time to time, that uses microfluidic Chips to perform High Throughput Screening for drug discovery.

7. Section 1.20 shall be deleted in its entirety and replaced with the following:

1.20 "microfluidic Chip" shall mean a device made of a substrate that [*], that employs electric field driven fluidics combined with electrophoretic separation in micro channels formed in such substrate that is intended to be used with HTS Chip Devices, Low Throughput Devices, Prototype HTS Chip Devices, Substitute Prototype Devices, ACLAmate Instruments or [*] Instruments and that is developed as part of the Project, and any improvements thereto that are developed by ACLARA.

8. Section 1.22 shall be deleted and replaced in its entirety with the following: