A.

$5,980 per month, payable in advance, the first installment to be paid on the execution of this Sublease and regular monthly installments in the amount of $5,980 per month to be paid on the 1^st day of each month thereafter in respect of each month of the subleasing prior to the End Date.

B.

Sublessee further agrees to pay in advance to Sublessor on the 1^st day of each month such Operating Expense as is required pursuant to the Major Lease, which for the Major Lessor’s FY 2017 is $844 per month.   If such amount is adjusted at the end of the Major Lessor’s fiscal year, any credit given by the Major Lessor shall be pro-rated according to the portion of the year in which this agreement is effective.  Sublessee likewise agrees to pay to Sublessor, on the 1^st day of each month, the monthly Operating Expense assessment for the Major Lessor’s FY 2018.  Any credits given by Major Lessor at the conclusion of the Major Lease for its FY 2018 Operating Expenses shall be paid over to the Sublessee.

C.

Sublessee further agrees to pay Sublessor for all Real Estate Tax Assessment charges imposed pursuant to the Major Lease during the term of this sublease.  Such charges are

payable quarterly and shall be pro-rated for the quarter in which this agreement becomes effective. The assessment to the Sublessor for the City of Newton Second Quarter of FY 2018 (October, November, and December) was $564.   Accordingly, Sublessee shall pay $188 to Sublessor on the Start Date of this agreement.  

D.

It is understood that upon the execution of this Sublease, Sublessee shall have deposited with Sublessor the sum of $13,648 as a Security Deposit as security for the faithful performance and observance by Sublessee of the terms, conditions, provisions and covenants of this Sublease, it being further understood however, that said deposit is not to be considered prepaid rent. In the event Sublessee defaults in respect to any of the terms, conditions, provisions and covenants of this Sublease, including, but not limited to the payment of Rent, Sublessor may use, apply or retain the whole or any part of the Security Deposit to the extent required for the payment of any Rent or any other sum as to which Sublessee is in default or for any sum which Sublessor may expend or may be required to expend by reason of Subessee's default with respect to this Sublease, including but not limited to any amount for which the Sublessee is liable under the article contained herein entitled "DEFAULT" provided, however, that such Security Deposit shall in no way be construed as liquidated damages for any default or breach of any term, condition, provision and covenant of this Sublease, nor shall Sublessor be required, because of said deposit, to waive its right under the article contained herein entitled "DEFAULT" to terminate this Sublease in the event of default. If, on the End Date the Sublessee shall not have been in default under the Sublease at any time and Sublessee shall have fully and faithfully complied with all of the terms, conditions, provisions and covenants of this Sublease, including, without limitation, payment of Rent when due, the Security Deposit shall be returned without interest.

A.

if to Sublessee, at One Gateway Center, Suite 351, Newton, Massachusetts 02458 or

B.

if to Sublessor, at 248 Summit Avenue, Brookline, Massachusetts 02446, or such place as Sublessor may designate in writing in the future,

Sublessor:

Sublessee:

/s/ Bradley A. MacDonald

Bradley A. MacDonald

Acer Therapeutics Inc.

By: /s/ Chris Schelling    

Chris Schelling

CEO & Founder

10/23/2017

Approved:

Commonwealth Development LLC as Trustee of Gateway Realty Trust

By: ________________________

Authorized Agent

A.

Landlord and Tenant are the parties to that certain Lease dated as of July 14, 1993, as most recently amended by Amendment Number Four, as of January 21, 2012 (as amended, "Master Lease");

B.

Tenant and Subtenant wish to enter into the Sublease;

C.

The Master Lease provides, inter alia, that Tenant may not enter into any sublease without Landlord's prior written approval; and

D.

Tenant and Subtenant have presented the fully executed Sublease (a true copy of which is attached hereto) to Landlord for Landlord's approval.

1.

Landlord hereby consents to the subleasing of the premises which Subtenant is leasing from Tenant (the “Subleased Premises”) pursuant to the Sublease (i) upon the terms and conditions set forth herein and (ii) subject to the terms of the Master Lease, including, without limitation, Landlord’s right to the net excess rent as set forth in Article 10.0 of the Master Lease, “ASSIGNMENT, MORTGAGING, SUBLETTING, ETC.”. Tenant and Subtenant hereby represent to Landlord that Tenant is not receiving any such net excess rent under the Sublease. Except for the foregoing consent by Landlord to the subleasing of the Subleased Premises pursuant to the Sublease, nothing in this Agreement shall operate as a consent by Landlord to or approval by Landlord of any of the particular provisions of the Sublease.

2.

Tenant and Subtenant hereby acknowledge that in the event of a conflict between the terms of this Consent and the Master Lease or Sublease, this Consent shall control.

3.

(a) In the event of Master Lease Termination (as hereinafter defined) prior to the termination of the Sublease, and subject to the provisions of Section 3(b) hereof, or in the event of Landlord's right to terminate Tenant's (and as a result Subtenant's) right of possession to the Subleased Premises and the interest of Tenant (and as a result Subtenant) therein, Landlord may, at its sole discretion, require Subtenant to assume and agree to perform Tenant's obligations under the Master Lease with respect to the Subleased Premises. Such assumption by Subtenant of each and every one of the obligations of Tenant under the Master Lease with respect to the Subleased Premises shall entitle the Subtenant to occupy the Subleased Premises leased pursuant to the Master Lease, but shall not relieve Tenant from any liability to Landlord under the Master Lease. In the event of such assumption, Subtenant agrees to execute and deliver at any time and from time to time, upon request of Landlord, any instruments which may be necessary or appropriate to evidence such assumption and Subtenant hereby irrevocably appoints Landlord as its attorney-in-fact, coupled with an interest, to execute on behalf of Subtenant any documents or instruments necessary to evidence such assumption.

4.

Neither the Master Lease, the Sublease nor this Consent shall be deemed, nor are such documents intended, to grant to Subtenant any rights whatsoever against Landlord. Subtenant hereby acknowledges and agrees that its sole remedy for any alleged or actual breach of its rights in connection with the Sublease shall be solely against Tenant. Subtenant acknowledges and agrees that it is not a third party beneficiary under the Master Lease and is not entitled to assert any of Tenant's rights thereunder against Landlord, whether in its own right or on behalf of Tenant.

5.

Neither this Consent nor the Sublease shall release Tenant from any existing or future duty, obligation or liability to Landlord pursuant to the Master Lease, nor shall this Consent or the Sublease change, modify or amend the Master Lease in any manner, except insofar as it constitutes Landlord's consent to Subtenant’s subleasing of the Subleased Premises as set forth in this Consent. Notwithstanding the generality of the foregoing: (a) neither the Sublease nor the Consent shall absolve Tenant from any requirement set forth in the Master Lease that Tenant obtain Landlord's prior written approval as required in the Master Lease, including without limitation, for any alterations, for any additional subleases, assignments or other dispositions of its interest in the Master Lease or the Premises (as defined in the Master Lease), or for any further sublease, assignment or other disposition of the Sublease, (b) Landlord shall be entitled to accept performance by either Tenant or Subtenant, and (c) any alterations, decorations, installations, removals, additions or improvements (including without limitation, the drilling of holes in the Subleased Premises or elsewhere in the building of which the Subleased Premises is a part (the “Building”)) in or to the Subleased Premises or the Building shall be subject to the requirements of the Master Lease, including without limitation, the necessity of obtaining Landlord’s prior written consent thereto.

6.

Subtenant and Tenant shall provide Landlord with a simultaneous copy of any default notice issued under the Sublease. In addition to Landlord's rights under Section 3 hereof, in the event Tenant is in default under any of the terms and provisions of the Master Lease, Landlord may elect to receive directly from Subtenant all sums due or payable to Tenant by Subtenant pursuant to the Sublease, and upon receipt of Landlord's notice, Subtenant shall thereafter pay to Landlord any and all sums becoming due or payable under the Sublease and Tenant shall receive from Landlord a corresponding credit for such sums actually received by Landlord against any and all payments then owing from Tenant. Neither the service of such written notice nor the receipt of such direct payments shall cause Landlord to assume any of Tenant's duties, obligations and/or liabilities under the Sublease, nor shall such event impose upon Landlord the duty or obligation to honor the Sublease, nor subsequently to accept any purported attornment by Subtenant. Tenant grants Landlord a security interest in all such payments due to Tenant from Subtenant, which security interest Landlord may perfect by filing a UCC-1 Financing Statement. Landlord shall credit payments actually received pursuant to this conditional assignment to Tenant's obligations under the Master Lease.

7.

Subtenant hereby acknowledges that it has read and has knowledge of all of the terms, provisions, rules and regulations of the Master Lease and agrees not to do or omit to do anything which would cause Tenant to be in breach of the Master Lease. Any such act or omission also shall constitute a breach of the Master Lease and this Consent shall entitle Landlord to recover any damage, loss, cost, or expense which it thereby suffers, from Tenant and/or Subtenant. Without limiting the foregoing, in the event of the failure of Subtenant to vacate the Subleased Premises upon the Master Lease Termination, and assuming Landlord has not elected to require Subtenant to assume and agree to perform Tenant's obligations under the Master Lease with respect to the Subleased Premises pursuant to Section 3(a) above, then Landlord shall be entitled to all of the rights and remedies against Subtenant that would be available to Landlord against Tenant holding over after a Master

8.

In the event of any litigation between the parties hereto with respect to the subject matter hereof, the unsuccessful party agrees to pay the successful party all reasonable costs, expenses and attorneys' fees incurred therein by the successful party, which amounts may be included as a part of a judgment rendered therein.

9.

The parties acknowledge that the Sublease and this Consent constitute the entire agreement between Tenant and Subtenant with respect to the subject matter thereof insofar as Landlord may be concerned, and that no amendment, termination, modification or change therein will be binding upon Landlord unless Landlord shall have given its prior written consent thereto.

10.

This Consent shall be binding upon and shall inure to the benefit of the parties' respective successors in interest and assigns, subject at all times, nevertheless, to all agreements and restrictions contained in the Master Lease, the Sublease, and herein, with respect to subleasing, assignment or other transfer and the foregoing shall not be deemed to limit or negate Landlord's rights to prohibit or condition its consent to a future dispossession of Tenant's or Subtenant's interests. The agreements contained herein constitute the entire understanding between parties with respect to the subject matter hereof, and supersede all prior agreements, written or oral, inconsistent herewith. Tenant and Subtenant warrant and agree that neither Landlord nor any of its agents or other representatives have made any representations concerning the Premises, the Subleased Premises, their condition, the Sublease or the Master Lease. This Consent may be executed in multiple counterparts, which when taken together shall constitute a complete document.

11.

Notice required or desired to be given hereunder shall be effective by reputable delivery service, proof of delivery required, addressed to parties at the addresses set forth in this Consent (and if no addresses are so listed, then to the Landlord at the address set forth in the Master Lease for the payment of rent, or to Tenant or Subtenant at the address of the Premises or of the Subleased Premises, respectively). Any party may change its address for notice by giving notice in the manner hereinabove provided.

12.

Tenant and Subtenant hereby agree, jointly and severally, to indemnify, hold harmless and defend Landlord from and against any loss, cost, expense, damage or liability, including, without limitation, reasonable attorneys' fees, incurred as a result of (a) any claim by any person or entity that it is entitled to a commission, finder's fee or like payment relating to or arising out of the Sublease, or (b) any claim by any person or entity in any way relating to or arising out of the Sublease, Subtenant’s use or occupancy of the Premises or any portion thereof, or any related agreements or dealings. Subtenant shall provide to Landlord, as if Subtenant were the Tenant, all of the insurance certificates required of Tenant under Article 9 of the Master Lease.

13.

Upon execution hereof, Tenant shall reimburse Landlord, as additional rent, for Landlord’s reasonable legal, professional, administrative, managerial and all other expenses (which expenses may include, without limitation, hourly fees for administrative and management personnel and an allocation for overhead and profit) related to the Sublease and this Consent.

By:/s/ Bradley A. MacDonald

Name: Bradley A. MacDonald

By: /s/ Chris Schelling

Name: Chris Schelling