Exhibit 4.2

XORTX THERAPEUTICS INC.

STOCK OPTION PLAN

The Company hereby establishes a stock option plan for directors, senior officers, Employees, Consultants, Consultant Company or Management Company Employees (as such terms are defined below) of the Company and its subsidiaries, or an Eligible Charitable Organization (collectively “Eligible Persons”), to be known as the “Stock Option Plan” (the “Plan”). The purpose of the Plan is to give to Eligible Persons, as additional compensation, the opportunity to participate in the success of the Company by granting to such individuals options, exercisable over periods of up to ten years, as determined by the board of directors of the Company, to buy shares of the Company at a price equal to the Market Price prevailing on the date the option is granted less applicable discount, if any, permitted by the policies of the Exchange and approved by the Board.

In this Plan, the following terms shall have the following meanings:

“Associate” means an “Associate” as defined in the National Instrument 45-106.

“Board” means the Board of Directors of the Company.

“Change of Control” means the acquisition by any person or by any person and all Joint Actors, whether directly or indirectly, of voting securities (as defined in the Securities Act) of the Company, which, when added to all other voting securities of the Company at the time held by such person or by such person and a Joint Actor, totals for the first time not less than fifty percent (50%) of the outstanding voting securities of the Company or the votes attached to those securities are sufficient, if exercised, to elect a majority of the Board of Directors of the Company.

“Company” means XORTX Therapeutics Inc. (formerly APAC Resources Inc.) and its successors.

“Consultant” means a “Consultant” as defined in NI 45-106.

“Consultant Company” means a corporation controlled or operated by a Consultant.

“CSA” means the Canadian Securities Administrators, and for British Columbia in particular, the B.C. Securities Commission.

“Disability” means any disability with respect to an Optionee which the Board, in its sole and unfettered discretion, considers likely to prevent permanently the Optionee from:

“Eligible Persons” has the meaning given to that term in section 1 hereof.

“Employee” means an “Employee” as defined in NI 45-106.

“Exchange” means the TSX Venture Exchange and, if applicable, any other stock exchange on which the Shares are listed.

“Expiry Date” means the date set by the Board under subsection 3.1 of the Plan, as the last date on which an Option may be exercised.

“Grant Date” means the date specified in the Option Agreement as the date on which an Option is granted.

“Insider” means an “Insider” as defined in the British Columbia Securities Act.

“Investor Relations Activities” means “Investor Relations Activities” as defined in the TSXV policies.

“Joint Actor” has the meaning defined in NI 62-103, The Early Warning System and Related Take-Over Bid and insider Reporting Issues.

“Management Company Employee” means an Employee of an “external management company” as such term is defined under Form 51-102F6 “Statement of Executive Compensation” in respect of financial years ending on or after December 31, 2008, of NI 51-102, “Continuous Disclosure Obligations” published by the CSA.

“Market Price” of Shares at any Grant Date means the last closing price per Share on the trading day immediately preceding the day on which the Company announces the grant of the option or, if the grant is not announced, on the Grant Date, or if the Shares are not listed on any stock exchange, “Market Price” of Shares means the price per Share on the over-the-counter market determined by dividing the aggregate sale price of the Shares sold by the total number of such Shares so sold on the applicable market for the last day prior to the Grant Date.

“NI 45-106” means NI 45-106, “Prospectus and Registration Exemptions” published by the CSA.

“Option” means an option to purchase Shares granted pursuant to this Plan.

“Option Agreement” means an agreement, in the form attached hereto as Schedule A, whereby the Company grants to an Optionee an Option.

“Optionee” means each of Eligible Persons granted an Option pursuant to this Plan and their heirs, executors and administrators.

“Option Price” means the price per Share specified in an Option Agreement, adjusted from time to time in accordance with the provisions of section 5.

“Option Shares” means the aggregate number of Shares which an Optionee may purchase under an Option.

“Plan” means this Stock Option Plan.

“Shares” means the common shares in the capital of the Company as constituted on the Grant Date provided that, in the event of any adjustment pursuant to section 5, “Shares” shall thereafter mean the shares or other property resulting from the events giving rise to the adjustment.

“Securities Act” means the Securities Act, R.S.B.C. 1996, c.418, as amended, as at the date hereof.

“Unissued Option Shares” means the number of Shares which have, at a particular time, been reserved for issuance upon the exercise of an Option, but which have not been issued, as adjusted from time to time in accordance with the provisions of section 5, such adjustments to be cumulative.

“Vested” means that an Option has become exercisable in respect of a ac of Option Shares by the Optionee pursuant to the terms of the Option Agreement.

The Board may from time to time authorize the allocation and issue of Options to specific Eligible Persons of the Company and its subsidiaries. The Option Price under each Option so allocated shall be not less than the Market Price on the Grant Date. The Expiry Date for each Option shall be set by the Board at the time of issue of the Option and shall not be more than ten years after the Grant Date. Options shall not be assignable (or transferable) by the Optionee. Both the Company and the Optionee are responsible for ensuring and confirming that the Optionee is a bona fide Eligible Person.

The maximum number of Shares which may be issuable pursuant to options granted under the Plan shall be that number equal to 10% of the Company’s issued share capital from time to time. The number of Shares reserved for issuance under the Plan and all of the Company’s other previously established or proposed share compensation arrangements:

The number of Shares which may be issuable under the Plan and all of the Company’s other previously established or proposed share compensation arrangements, within a one-year period:

Each Option shall be confirmed by the execution of an Option Agreement. Each Optionee shall have the option to purchase from the Company the Option Shares at the time and in the manner set out in the Plan and in the Option Agreement applicable to that Optionee. For stock options to Employees, Consultants, Consultant Company or Management Company Employees, each of the Company and the Optionee is representing herein and in the applicable Option Agreement that the Optionee is a bona fide Employee, Consultant, Consultant Company or Management Company Employee, as the case may be, of the Company or its subsidiary. The execution of an Option Agreement shall constitute conclusive evidence that it has been completed in compliance with this Plan.

Subject to subsections 4.3 and 4.4, an Option shall be granted as fully Vested on the Grant Date, and may be exercised to purchase any number of Shares up to the number of Unissued Option Shares at any time after the Grant Date, provided that this Plan has been previously approved by the shareholders of the Company, where such prior approval is required by Exchange policies, up to 4:00 p.m. local time on the Expiry Date and shall not be exercisable thereafter.

The Option shall be exercisable by delivering to the Company a notice specifying the number of Shares in respect of which the Option is exercised together with payment in full of the Option Price for each such Share. Upon notice and payment there will be binding contract for the issue of the Shares in respect of which the Option is exercised, upon and subject to the provisions of the Plan. Delivery of the Optionee’s certified cheque or bank draft payable to the Company in the amount of the Option Price shall constitute payment of the Option Price unless the certified cheque is not honoured upon presentation for any reason, in which case the Option shall not have been validly exercised.

An Option shall be granted hereunder as fully Vested, unless a vesting schedule is imposed by the Board as a condition of the grant on the Grant Date; and provided that if the Option is being granted to an Eligible Person who is providing Investor Relations Activities to the Company, then the Option must vest in stages over not less than 12 months and no more than one-quarter (1/4) of such Options may be vested in any three (3) month period.

If an Optionee ceases to be an Eligible Person, his or her Option shall be exercisable as follows:

If the Optionee ceases to be an Eligible Person, due to his or her death or Disability or, in the case of an Optionee that is a company, the death or Disability of the person who provides management or consulting services to the Company or to any entity controlled by the Company, the Option then held by the Optionee shall be exercisable to acquire Vested Unissued Option Shares at any time up to but not after the earlier of:

If the Optionee, or in the case of a Management Company Employee or a Consultant Company, the Optionee’s employer, ceases to be an Eligible Person as a result of termination for cause, as that term is interpreted by the courts of the jurisdiction in which the Optionee, or, in the case of a Management Company Employee or a Consultant Company, of the Optionee’s employer, is employed or engaged; any outstanding Option held by such Optionee on the date of such termination shall be cancelled as of that date.

If the Optionee or, in the case of a Management Company Employee or a Consultant Company, the Optionee’s employer, ceases to be an Eligible Person due to his or her retirement at the request of his or her employer earlier than the normal retirement date under the Company’s retirement policy then in force, or due to his or her termination by the Company other than for cause, or due to his or her voluntary resignation, the Option then held by the Optionee shall be exercisable to acquire Vested Unissued Option Shares at any time up to but not after the earlier of the Expiry Date and the date which is 90 days after the Optionee or, in the case of a Management Company Employee or a Consultant Company, the Optionee’s employer, ceases to be an Eligible Person.

If a bona fide offer (an “Offer”) for Shares is made to the Optionee or to shareholders of the Company generally or to a class of shareholders which includes the Optionee, which Offer, if accepted in whole or in part, would result in the offeror becoming a control person of the Company, within the meaning of subsection 1(1) of the Securities Act, the Company shall, immediately upon receipt of notice of the Offer, notify each Optionee of full particulars of the Offer, whereupon the Option Shares subject to such Option may be exercised in whole or in part by the Optionee so as to permit the Optionee to tender the Option Shares received upon such exercise, pursuant to the Offer. However, if:

If at any time when an Option granted under the Plan remains unexercised with respect to any Unissued Option Shares, an Offer is made by an offeror, the Directors may, upon notifying each Optionee of full particulars of the Offer, declare all Option Shares issuable upon the exercise of Options granted under the Plan, are Vested (subject to the proviso below), and declare that the Expiry Date for the exercise of all unexercised Options granted under the Plan is accelerated so that all Options will either be exercised or will expire prior to the date upon which Shares must be tendered pursuant to the Offer, provided that where an Option was granted to a consultant providing Investor Relations Activities, the Directors declaration that Option Shares issuable upon the exercise of such Options granted under the Plan be Vested with respect to such Option Shares, is subject to prior approval of the Exchange. The Directors shall give each Optionee as much notice as possible of the acceleration of the Options under this section, except that not less than five (5) business days and not more than 35 days notice is required.

If a Change of Control occurs, all Option Shares subject to each outstanding Option may be exercised in whole or in part by the Optionee.

If the Optionee, or, in the case of a Management Company Employee or a Consultant Company, the Optionee’s employer, retires, resigns or is terminated from employment or engagement with the Company or any subsidiary of the Company, the loss or limitation, if any, by the cancellation of the right to purchase Option Shares under the Option Agreement shall not give rise to any right to damages and shall not be included in the calculation of nor form any part of any severance allowance, retiring allowance or termination settlement of any kind whatsoever in respect of such Optionee.

Any Unissued Option Shares not acquired by an Optionee under an Option which has expired, and any Option Shares acquired by an Optionee under an Option when exercised, may be made the subject of a further Option granted pursuant to the provisions of the Plan.

In the event the Expiry Date of an Option falls on a date during a trading black out period that has been self imposed by the Company, the Expiry Date of the Option will be extended to the 10^th business day following the date that the self imposed trading black out period is lifted by the Company. For greater certainty, the Expiry Date of an Option will not be extended in the event a cease trade order is issued by a securities regulatory authority against the Company or an Optionee.

Whenever the Company issues Shares to all or substantially all holders of Shares by way of a stock dividend or other distribution, or subdivides all outstanding Shares into a greater number of Shares, or combines or consolidates all outstanding Shares into a lesser number of Shares (each of such events being herein called a “Share Reorganization”) then effective immediately after the record date for such dividend or other distribution or the effective date of such subdivision, combination or consolidation, for each Option:

Subject to the prior approval of the Exchange, whenever the Company issues by way of a dividend or otherwise distributes to all or substantially all holders of Shares:

Whenever there is:

(any such event being herein called a “Corporate Reorganization”) the Optionee will have an option to purchase (at the times, for the consideration, and subject to the terms and conditions set out in the Plan) and will accept on the exercise of such option, in lieu of the Unissued Option Shares which he would otherwise have been entitled to purchase, the kind and amount of shares or other securities or property that he would have been entitled to receive as a result of the Corporate Reorganization if, on the effective date thereof, he had been the holder of all Unissued Option Shares or if appropriate, as otherwise determined by the Directors.

If any questions arise at any time with respect to the Option Price or number of Unissued Option Shares deliverable upon exercise of an Option following a Share Reorganization, Special Distribution or Corporate Reorganization, such questions shall be conclusively determined by the Company’s auditor, or, if they decline to so act, any other firm of Chartered Accountants in Vancouver, British Columbia, that the Directors may designate and who will have access to all appropriate records and such determination will be binding upon the Company and all Optionees.

Any adjustment to the Option Price or the number of Unissued Option Shares purchasable under the Plan pursuant to the operation of any one of subsection 5.1, 5.2 or 5.3 is subject to the approval of the Exchange where required pursuant to their policies, and compliance with the applicable securities rules or regulations of any other governmental authority having jurisdiction.

Neither this Plan nor any of the provisions hereof shall confer upon any Optionee any right with respect to employment or continued employment with the Company or any subsidiary of the Company or interfere in any way with the right of the Company or any subsidiary of the Company to terminate such employment.

The Plan shall be effective immediately upon the approval of the Board of directors of the Company, where the Company is a non-reporting issuer. If the Company is a reporting issuer whose Shares are listed on any Exchange, then the Plan shall be effective only upon the approval of the shareholders of the Company given by way of an ordinary resolution of the disinterested shareholders in the case of a new Plan, and the written acceptance of the Plan by the Exchange where such prior approval is required by the policies of the Exchange. Any Options granted under this Plan before such approval shall only be exercised upon the receipt of such approval, where it is required by the policies of the Exchange. The obligation of the Company to sell and deliver Shares in accordance with the Plan is subject to compliance with the policies of the Exchange and applicable securities rules or regulations of any governmental authority having jurisdiction. If any Shares cannot be issued to any Optionee for any reason, including, without limitation, the failure to comply with such policies, rules or regulations, then the obligation of the Company to issue such Shares shall terminate and any Option Price paid by an Optionee to the Company shall be immediately refunded to the Optionee by the Company.

The Directors shall, without limitation, have full and final authority in their discretion, but subject to the express provisions of the Plan, to interpret the Plan, to prescribe, amend and rescind rules and regulations relating to the Plan and to make all other determinations deemed necessary or advisable in respect of the Plan. Except as set forth in subsection 5.4, the interpretation and construction of any provision of the Plan by the Directors shall be final and conclusive. Administration of the Plan shall be the responsibility of the appropriate officers of the Company and all costs in respect thereof shall be paid by the Company.

As a condition of and prior to participation of the Plan any Optionee shall on request authorize the Company in writing to withhold from any remuneration otherwise payable to him or her any amounts required by any taxing authority to be withheld for taxes of any kind as a consequence of his or her participation in the Plan.

The Directors may from time to time, subject to applicable law and to the prior approval, if required, of the Exchange or any other regulatory body having authority over the Company or the Plan, suspend, terminate or discontinue the Plan at any time, or amend or revise the terms of the Plan or of any Option granted under the Plan and the Option Agreement relating thereto, provided that no such amendment, revision, suspension, termination or discontinuance shall in any manner adversely affect any option previously granted to an Optionee under the Plan without the consent of that Optionee. Any amendments to the Plan or options granted to Insiders thereunder will be subject to the approval of the shareholders, where such approval is required by the policies of the Exchange.

A notice given to the Company shall be in writing, signed by the Optionee and delivered to the head business office of the Company.

The Company makes no representation or warranty as to the future market value of any Shares issued in accordance with the provisions of the Plan.

If any provision of the Plan or any Option Agreement contravenes any law or any order, policy, by-law or regulation of any regulatory body or Exchange having authority over the Company or the Plan, then such provision shall be deemed to be amended to the extent required to bring such provision into compliance therewith.

No Optionee may assign any of his or her rights under the Plan or any Option granted thereunder.

An Optionee shall have no rights whatsoever as a shareholder of the Company in respect of any of the Unissued Option Shares (including, without limitation, voting rights or any right to receive dividends, warrants or rights under any rights offering).

In the event of any conflict between the provisions of this Plan and an Option Agreement, the provisions of this Plan shall govern.

The Plan and each Option Agreement issued pursuant to the Plan shall be governed by the laws of the Province of British Columbia.

Time is of the essence of this Plan and of each Option Agreement. No extension of time will be deemed to be or to operate as a waiver of the essentiality of time.

This Plan and the Option Agreement sets out the entire agreement between the Company and the Optionees relative to the subject matter hereof and supersedes all prior agreements, undertakings and understandings, whether oral or written.

SCHEDULE A

XORTX THERAPEUTICS INC.

STOCK OPTION PLAN
OPTION AGREEMENT

This Option Agreement is entered into between XORTX Therapeutics Inc. (the “Company”) and the Optionee named below pursuant to the Company Stock Option Plan (the “Plan”), a copy of which is attached hereto, and confirms that:

(Where “Personal Information” means any information about the Optionee, and includes the information contained in the tables, as applicable), all on the terms and subject to the conditions set out in the Plan.

By signing this Option Agreement, the Optionee acknowledges that the Optionee has read and understands the Plan and agrees to the terms and conditions of the Plan and this Option Agreement.

IN WITNESS WHEREOF the parties hereto have executed this Option Agreement as of the ● day of ●, 20●.