Exhibit 10.22

RIGHT OF FIRST REFUSAL AGREEMENT

THIS RIGHT OF REFUSAL AGREEMENT (this “ Agreement ”) is entered into as of May 5, 2008, by and among (i) the entities listed as “grantors” on the signature pages of this Agreement (each a “ Grantor ” and collectively the “ Grantors ”), and (ii) Senior Housing Properties Trust, a Maryland real estate investment trust (“ SNH ”).

WITNESSETH:

WHEREAS,   the Grantors have agreed to grant to SNH a right of first refusal to purchase certain medical office buildings, clinical laboratory buildings and biomedical, pharmaceutical and laboratory buildings, listed on Schedule A hereto and as more particularly described on Schedules B-1 through B -35 hereto (each a “ ROFR Property ”, and collectively, the “ ROFR Properties ”), subject to, and upon, the terms and conditions of this Agreement;

NOW, THEREFORE ,   for and in consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by each party hereto, the parties hereto hereby agree as follows:

1.             Right of First Refusal to Purchase .    The Grantors hereby grant to SNH, subject to the Declaration of Trust of HRPT Properties Trust (“ HRPT ”) and subject to and in accordance with the terms and conditions of this Section 1 , the right of first refusal to purchase the ROFR Properties.

(a)           If a Grantor desires to sell a ROFR Property, or if a Grantor shall otherwise receive an offer from a party other than SNH, or its affiliates, for any such sale or transfer which such Grantor intends to accept, then such Grantor shall, prior to entering into an agreement with respect to such sale, provide, or shall cause to be provided, written notice (the “ ROFR Notice ”) to SNH of its intention to effect such a transaction, which ROFR Notice shall specify the cash purchase price for the ROFR Property, the terms of payment, the closing date and the other material business terms of such transaction. SNH shall have fifteen (15) business days after receipt of the ROFR Notice to notify such Grantor in writing (the “ ROFR Acceptance Notice ”) of its intent to purchase the ROFR Property on the terms and conditions set forth in the ROFR Notice. The negotiation and execution of a mutually acceptable purchase and sale agreement must occur no more than fifteen (15)

calendar days after the date on which SNH gave the Grantor the ROFR Acceptance Notice.

(b)           If SNH fails or elects not to give timely a ROFR Acceptance Notice, or if a mutually acceptable purchase and sale agreement is not executed within fifteen (15) calendar days after the date on which SNH gave the Grantor the ROFR Acceptance Notice, then the Grantor shall have three hundred sixty-five (365) days from the date thereof to sell the ROFR Property to any third party (including any party making the offer set forth in subsection (a) above) for a purchase price not less than 95% of the cash purchase price specified in the ROFR Notice. If such sale shall not have occurred within such three hundred sixty-five (365) day period, then the sale of the ROFR Property shall once again be subject to the right of first refusal set forth in this Agreement.

(c)           Excluded Transactions .    The following transactions shall be excluded from the right of first refusal contained herein:

(i)            A transfer of any ROFR Property to a governmental or quasi-governmental agency (collectively, the “ Agency ”) as part of a tax reduction or tax abatement program in which a Grantor leases a ROFR Property back from the Agency; provided, however, a transfer or assignment of such Grantor’s interest as tenant in the lease of the ROFR Property from the Agency shall be subject to the terms and conditions of this Agreement and the right of first refusal granted herein;

(ii)           A transfer of a ROFR Property to an entity that is wholly owned, directly or indirectly, by HRPT so long as such entity continues to be wholly owned directly or indirectly by HRPT;

(iii)          A sale of a ROFR Property to any tenant or other party having a right of first refusal or offer to purchase in effect on the date hereof on the terms and conditions of such right of first refusal or offer to purchase;

(iv)          A sale of the ROFR Property to the appropriate condemning authority pursuant to eminent domain or under threat of eminent domain;

(v)           Any financing, reorganization, recapitalization,

reclassification, exchange of shares or spin-offs to HRPT shareholders, in each case where there is no Change of Control.

2.             Change of Control .   For the purposes of this Agreement, a direct or indirect Change of Control shall be deemed a sale. HRPT shall give SNH prompt written notice of the occurrence of any Change of Control with respect to any Grantor. In such event, subject to the provisions of the Declaration of Trust of HRPT, SNH shall have the option, exercisable by written notice to HRPT within sixty (60) days after HRPT’s notice to SNH regarding such Change of Control, to purchase any or all of the ROFR Properties owned by the Grantor to which such Change of Control applies (or any Subsidiary of such Grantor), for a purchase price equal to, with respect to each such ROFR Property, the Change of Control Purchase Price.

As used in this Agreement:

(i)            “ Affiliated Person ”     shall mean, with respect to any Person, (a)  in the case of any such Person which is a partnership, any partner in such partnership, (b) in the case of any such Person which is a limited liability company, any member of such company, (c) any other Person which is a Parent, a Subsidiary, or a Subsidiary of a Parent with respect to such Person or to one or more of the Persons referred to in the preceding clauses (a) and (b), (d) any other Person who is an officer, director, trustee or employee of, or partner in or member of, such Person or any Person referred to in the preceding clauses (a), (b) and (c), and (e) any other Person who is a member of the Immediate Family of such Person or of any Person referred to in the preceding clauses (a) through (d).

(ii)           “ Capitalization Value ”     shall mean, with respect to any ROFR Property, the Net Operating Income of such ROFR Property divided by the greater of (a) treasuries plus 350 basis points and (b) nine percent (9%).

(iii)          “ Change of Control ”     shall mean, with respect to any Grantor, (a) the acquisition by any Person, or two or more Persons acting in concert, of beneficial ownership (within the meaning of Rule 13d-3 of the SEC) of 9.8% or more in violation of the Declaration of Trust of HRPT, or rights, options or warrants to acquire 9.8% or more, of the outstanding shares of voting stock or other voting interests of a Grantor or its direct or indirect Parent in violation of the Declaration of Trust of HRPT, as the case may be, or the power to direct the management and policies of a Grantor or its direct or indirect

Parent, directly or indirectly, (b) the merger or consolidation of a Grantor or its direct or indirect Parent with or into any other Person (other than the merger or consolidation of any Person into a Grantor or direct or indirect Parent that does not result in a Change of Control of a Grantor or direct or indirect Parent under clauses (a), (c) or (d) of this definition), (c) any one or more sales or conveyances to any Person of all or any material portion of the assets (including capital stock or other equity interests) or business of HRPT, or (d) the cessation, for any reason, of the individuals who at the beginning of any twenty-four (24) consecutive month period (commencing on the date of this Agreement) constituted the board of directors of a Grantor or its direct or indirect Parent (together with any new directors whose election by such board or whose nomination for election by the shareholders of a Grantor or its direct or indirect Parent, as the case may be, was approved by a vote of a majority of the directors then still in office who were either directors at the beginning of any such period or whose election or nomination for election was previously so approved) to constitute a majority of the board of directors of a Grantor or its direct or indirect Parent then in office.

(iv)          “ Change of Control Purchase Price ”     shall mean, with respect to any ROFR Property which is less than fifty percent (50%) leased, the Fair Market Value of such ROFR Property and, with respect to any ROFR Property which is fifty percent (50%) or more leased, the lesser of (x) the Fair Market Value of such ROFR Property and (y) the Capitalization Value of such ROFR Property.

(v)           “ Entity ”     shall mean any corporation, general or limited partnership, limited liability company or partnership, stock company or association, joint venture, association, company, trust, bank, trust company, land trust, business trust, real estate investment trust, cooperative, any government or agency, authority or political subdivision thereof or any other entity.

(vi)          “ Fair Market Value ”     shall mean, wit