SIXTH AMENDMENT TO LEASE

Exhibit 10.1

SIXTH AMENDMENT TO LEASE

SIXTH AMENDMENT TO LEASE dated as of this 28^th day of October, 2009 by and between MORTIMER B. ZUCKERMAN AND EDWARD H. LINDE, AS TRUSTEES OF TRACER LANE TRUST II, under Declaration of Trust dated May 30, 2000 recorded with the Middlesex South District Registry of Deeds in Book 31451, Page 498, but not individually (“Landlord”) and UNICA CORPORATION, a Delaware corporation (as successor by merger to Unica Corporation, a Massachusetts corporation, “Tenant”).

RECITALS

By Lease dated December 20, 2002 (the “Original Lease”), Landlord did lease to Tenant and Tenant did hire and lease from Landlord certain premises containing 26,460 square feet of rentable floor area (referred to in the Original Lease as the “Rentable Floor Area of the Premises” and hereinafter sometimes referred to as the “Rentable Floor Area of the Initial Premises”) on the second (2^nd) floor of the building (the “Building”) known as and numbered 170 Tracer Lane, Waltham, Massachusetts (referred to in the Original Lease as the “Premises” and hereinafter sometimes referred to as the “Initial Premises”).

By letter dated December 20, 2002 (the “December 2002 Letter”), Landlord and Tenant agreed upon signage rights to be provided to Tenant under certain circumstances.

By First Amendment to Lease dated December 23, 2003 (the “First Amendment”), Landlord and Tenant increased the size of the Premises by adding thereto 13,734 square feet of rentable floor area (the “Rentable Floor Area of the First Additional Premises”) located on the first (1^st) floor of the Building, which space is shown as Exhibit A attached to such First Amendment (the “First Additional Premises”).

By Second Amendment to Lease dated October 14, 2004 (the “Second Amendment”), Landlord and Tenant increased the size of the Premises by adding thereto 4,679 square feet of rentable floor area (the “Rentable Floor Area of the Second Additional Premises”) located on the first (1^st) floor of the Building, which space is shown as Exhibit A attached to such Second Amendment.

By Third Amendment to Lease dated December 30, 2004 (the “Third Amendment”), Landlord and Tenant (i) extended the Term of the Lease for one (1) year upon the terms set forth in such Third Amendment and (ii) increased the size of the Premises by adding thereto 26,570 square feet of rentable floor area (the “Rentable Floor Area of the Third Additional Premises”) located on the third (3^rd) floor of the Building, which space is shown as Exhibit A attached to such Third Amendment.

By Fourth Amendment to Lease dated February 12, 2007 (the “Fourth Amendment”), Landlord and Tenant increased the size of the Premises by adding thereto 1,815 square feet of rentable floor area (the “Rentable Floor Area of the Fourth Additional Premises”) located on the first (1^st) floor of the Building, which space is shown on Exhibit A attached to such Fourth Amendment.

By Fifth Amendment to Lease dated October 2, 2008 (the “Fifth Amendment”), Landlord and Tenant extended the Term of the Lease for one (1) year upon the terms set forth in such Fifth Amendment.

Landlord and Tenant have agreed to extend the Term of the Lease for one (1) period of five (5) years upon all of the same terms and conditions set forth in the Lease except as set forth in this Sixth Amendment to Lease (the “Sixth Amendment”).

Landlord and Tenant are entering into this instrument to set forth said extension of the Term of the Lease and to amend the Lease.

NOW THEREFORE, in consideration of One Dollar ($1.00) and other good and valuable consideration in hand this date paid by each of the parties to the other, the receipt and sufficiency of which are hereby severally acknowledged, and in further consideration of the mutual promises herein contained, Landlord and Tenant hereby agree to and with each other as follows:

(B) If Tenant desires to exercise the option to extend the Term, then Tenant shall give notice (the “Exercise Notice”) to Landlord, not earlier than eighteen (18) months nor later than fifteen (15) months prior to the expiration of the Third Extended Term exercising such option to extend. Promptly after Landlord’s receipt of the Exercise Notice Landlord shall provide Landlord’s quotation of a proposed Annual Fixed Rent which shall represent a rate that Landlord believes is equal to the fair market rent for the entire Premises for the Fourth Extended Term (“Landlord’s Rent Quotation”). If at the expiration of thirty (30) days after the date when Landlord provides such quotation to Tenant (the “Negotiation Period”), Landlord and Tenant have not reached agreement on a determination of an Annual Fixed Rent for the Fourth Extended Term and executed a written instrument memorializing the extension of the Term of the Lease pursuant to such agreement on the Annual Fixed Rent for the Fourth Extended Term, then Tenant shall have the right, for ten (10) days after the expiration of the Negotiation Period, to either (i) make a request to Landlord for a broker determination (the “Broker Determination”) of the Prevailing Market Rent for the entire Premises for the Fourth Extended Term, which Broker Determination shall be made in the manner set forth in Exhibit A attached hereto, or (ii) revoke its Exercise Notice.

If Landlord and Tenant shall have reached agreement during the Negotiation Period, then the Annual Fixed Rent for the Fourth Extended Term shall be as agreed upon by Landlord and Tenant. If Tenant timely shall have requested the Broker Determination, then the Annual Fixed Rent for the Fourth Extended Term shall be the Prevailing Market Rent as determined by the Broker Determination. If Tenant timely revokes its Exercise Notice, the Lease shall expire as of the expiration date of the Third Extended Term. If Tenant does not timely request the Broker Determination, then Tenant shall be deemed to have revoked its Exercise Notice.

(C) Upon either (i) the agreement of Landlord and Tenant during the Negotiation Period on an Annual Fixed Rent for the Fourth Extended Term or (ii) the timely request by Tenant for a Broker Determination, the Lease and the Lease Term thereof shall be extended, for the Fourth Extended Term, without the necessity for the execution of any additional documents, except that Landlord and Tenant agree to enter into an instrument in writing setting forth the Annual Fixed Rent for the Fourth Extended Term but the failure to so enter into such a written instrument shall not negate the exercise of the option to extend. Notwithstanding anything herein contained to the contrary, in no event shall the Lease Term hereof be extended for more than three (3) years after the expiration of the Third Extended Term.

(B) Effective as of September 1, 2009 and continuing through the expiration of the Third Extended Term, Annual Fixed Rent shall be payable by Tenant as follows:

(C) Annual Fixed Rent for the extension option period shall be payable as determined in accordance with Section 2 of this Sixth Amendment.

“Base Operating Expenses” means Landlord’s Operating Expenses (as hereinafter defined in Section 2.6) for calendar year 2010, being the period from January 1, 2010 through December 31, 2010.

(B) For purposes of calculating Tenant’s payments for real estate taxes pursuant to Section 2.7 of the Lease, for that portion of the Lease Term prior to September 1, 2009 the definition of “Base Taxes” contained in Section 2.7 of the Lease shall be unchanged. For that portion of the Lease Term on and after September 1, 2009, for such purposes, the definition of “Base Taxes” shall be deleted in its entirety and substituted with the following:

“Base Taxes” means Landlord’s Tax Expenses (as hereinabove defined in Section 2.7) for fiscal tax year 2011 (being the period from July 1, 2010 and through June 30, 2011).

(B) It is understood and agreed that Landlord shall be performing certain work in the Premises as set forth on Exhibit B attached hereto (the “Landlord’s Work”). The items of Landlord’s Work delineated on Exhibit B as being part of the turnkey scope (“Turnkey Work”) shall be at Landlord’s sole cost and expense and the items of Landlord’s Work delineated as not included in the turnkey scope or any changes to Exhibit B requested by Tenant shall be paid for by Tenant. Landlord shall use reasonable speed and diligence to perform the Landlord’s Work; provided, however, that Landlord shall not be liable to Tenant for the failure to complete the Landlord’s Work by any given date so long as Landlord has used reasonable speed and diligence as aforesaid. In addition, it is acknowledged and agreed that Landlord will be performing the Landlord’s Work in the Premises while Tenant is in occupancy thereof, and accordingly Landlord and Tenant agree to cooperate with each other in good faith to insure that the Landlord’s Work can be undertaken in an efficient and cost-effective manner and so as to minimize any unreasonable interference with Tenant’s business operations in the Premises (consistent with the nature of the work being performed).

(C) Landlord shall provide to Tenant a special allowance in the amount $183,145.00 (the “Tenant Allowance”). The Tenant Allowance shall be used and applied by Landlord solely on account of the cost of (i) any items of Landlord’s Work delineated on Exhibit B as not being included within the Turnkey Work, (ii) any changes to Exhibit B requested by Tenant during the performance of the Landlord’s Work and (iii) any subsequent tenant improvements to be performed by Landlord as requested by Tenant prior to August 31, 2011 and reviewed and approved by Landlord in accordance with the terms and provisions of the Lease (the items described in the foregoing clauses (i), (ii) and (iii) being hereinafter referred to collectively as “Additional Work”). In no event shall Landlord’s obligations to pay or reimburse Tenant for any of the costs of Additional Work exceed the total Tenant Allowance. Notwithstanding the foregoing, Landlord shall be under no obligation to apply any portion of the Tenant Allowance for any purposes other than as provided in this Section 5. In addition, in the event that (x) Tenant is in default under the Lease or (y) there are any liens which are not bonded to the reasonable satisfaction of Landlord against Tenant’s interest in the Lease or against the Building or the Site arising out of any work performed by Tenant or any litigation in which Tenant is a party or (z) Tenant shall have not requested prior to August 31, 2011 that a particular item of Additional Work be performed, then, from and after the date of such event (“Event”), Landlord shall have no further obligation to fund any portion of the Tenant Allowance and Tenant shall be obligated to pay, as Additional Rent, all costs of the Additional Work in excess of that portion of the Tenant Allowance funded by Landlord through the date of the Event. Further, the Tenant Allowance shall only be applied towards the cost of leasehold improvements and in no event shall Landlord be required to make application of any portion of the Tenant Allowance towards Tenant’s personal property, trade fixtures or moving expenses or on account of any supervisory fees, overhead, management fees or other payments to Tenant, or any partner or affiliate of Tenant. In the event that the costs of the Additional Work are less than the Tenant Allowance, Tenant shall not be entitled to any payment or credit nor shall there be any application of the same toward Annual Fixed Rent or Additional Rent owed by Tenant under the Lease. In the event that the costs of the Additional Work (together with a construction management fee in an amount equal to four percent (4%) of the costs of the Additional Work) exceed the Tenant Allowance, such excess costs are hereinafter referred to as “Tenant Plan Excess Costs” and shall be paid by Tenant as Additional Rent in accordance with subsection (D) below.

(D) To the extent, if any, that there are Tenant Plan Excess Costs, Tenant shall pay such Tenant Plan Excess Costs to Landlord, as Additional Rent, within ten (10) days after billing therefor from time to time during the performance of the component of Additional Work at issue, in the proportion that the Tenant Plan Excess Costs bears to the overall cost of the component of Additional Work at issue.

(E) Provided that Tenant has made its paint and carpet selections in a timely manner, Landlord agrees to commence Landlord’s Work within sixty (60) days after the full execution of this Sixth Amendment by Landlord and Tenant.

(B) Landlord warrants and represents that Landlord has not dealt with any broker in connection with the consummation of this Sixth Amendment other than the Broker and in the event any claim is made against Tenant relative to dealings by Landlord with brokers, other than the Broker, Landlord shall defend the claim against Tenant with counsel of Landlord’s selection and save harmless and indemnify Tenant on account of loss, cost or damage which may arise by reason of such claim.

Page Ends Here

1

EXECUTED as a sealed instrument as of the date and year first above written.

EXHIBIT A

BROKER DETERMINATION OF PREVAILING MARKET RENT

Where in the Sixth Amendment to Lease to which this Exhibit is attached provision is made for a Broker Determination of Prevailing Market Rent, the following procedures and requirements shall apply:

2

EXHIBIT B

TURNKEY SCOPE

Boston Properties Tenant Work Letter 170 Tracer Lane

DELINEATION OF TENANT IMPROVEMENT TURN-KEY SCOPE

3

Boston Properties Tenant Work Letter 170 Tracer Lane

DELINEATION OF TENANT IMPROVEMENT TURN-KEY SCOPE

4