Settlement Agreement, dated as of March 8, 2019, by and among X4 Pharmaceuticals, Inc. (formerly Arsanis, Inc.), Artemis AC Corp., X4 Therapeutics, Inc. (formerly X4 Pharmaceuticals, Inc.), Arsanis Biosciences GmbH and sterreichische Forschungsfrderungsgesellschaft GmbH

Exhibit 10.1

Exemption from stamp duties according to Sec. 14(2) of the Act on the Establishment of the Austrian Research Promotion Agency (Forschungsförderungsgesellschaftsgesetz).

SETTLEMENT AGREEMENT

concluded between

ARSANIS Biosciences GmbH

Arsanis, Inc.

Artemis AC Corp.

X4 Pharmaceuticals, Inc.

and

Österreichische Forschungsförderungsgesellschaft mbH

This Settlement Agreement (“Agreement”) is concluded between the following Parties (“Parties”):

Subject to the terms and conditions of this Agreement, Arsanis AT and FFG wish to enter into a full and final settlement with regard to the subject matter described under Section 2.5 to 2.7 of this Agreement.

The Parties agree as follows:

Arsanis AT shall repay the loans granted under the Subsidy Agreements until 30 June 2021 in accordance with the following amended (accelerated) payment schedule:

In case of a default of Arsanis AT with payments under the accelerated payment schedule FFG shall provide Arsanis AT with a reminder giving Arsanis AT a minimum 14 (fourteen) day grace period to effect the outstanding payment. A copy of such letter shall be sent to Arsanis Inc.

The regular interest to be paid in connection with the loans shall be paid by Arsanis AT in accordance with the provisions of and at the interest rates agreed in the Subsidy Agreements. Such interest shall accrue for each loan until its respective date of actual repayment. The interest shall be paid by Arsanis AT upon receipt of an invoice from FFG on a half-yearly basis and any remaining amount of interest at the date of actual repayment of the respective loan. Such invoice shall provide for a minimum payment term of two (2) weeks. FFG has the right to collect interest by auto-debiting a bank account of Arsanis AT for all interest amounts, consistent with its current practice. FFG will inform Arsanis AT at the time of sending the respective invoice in case it does not intend to exercise the latter right.

In case of a default of Arsanis AT with interest payments FFG shall provide Arsanis AT with a reminder giving Arsanis AT a minimum 14 (fourteen) day grace period to effect the outstanding interest payments. A copy of such letter shall be sent to Arsanis Inc.

Beginning from a date that is no more than fourteen (14) days from the closing of a financing of Arsanis Inc. following the closing of the Merger between X4 and Artemis, but in any event from 30 April 2019, Arsanis AT shall maintain a cash balance equal to at least 70 (seventy) per cent of the then current total principal amount of FFG loans outstanding at any point of time until all principal amounts of loans are fully repaid. The cash balance shall be maintained by Arsanis AT in a bank account held with an Austrian bank.

Arsanis AT shall maintain an Austrian site with a minimum number of full-time equivalents of eight (8) employees until at least 31 December 2021. In case of employees leaving Arsanis AT, either because of an employee’s resignation or because of dismissal, Arsanis AT is granted a reasonable time period for replacement of such employees. FFG acknowledges that such reasonable time period may vary from time to time depending on the position and qualification of the respective employee(s), but that such time period shall not exceed three (3) months save in case of a specialist skilled employee’s resignation or dismissal for cause in which case Arsanis AT shall, promptly following an unsuccessful lapse of such three (3) months period, submit a report to FFG setting out which efforts Arsanis AT has undertaken to seek a suitable replacement employee(s).

The intellectual property (including but not limited to patents, utility patents, designs, trademarks, trade names, domain names, logos, copyright, rights under license agreements, recipes, formulas and know-how) (“IP”) which generated or may be generated (if any) from or in relation to the projects funded by FFG under the Subsidy Agreements (which, for the sake of clarity, the parties agree does not include ASN500) shall remain part of the assets of Arsanis AT at least until 31 December 2021. While Arsanis AT is not under any obligation to continue to develop such IP, it agrees that in the event that it licenses or provides rights to such IP to any third party it will receive arm’s length compensation as consideration for at least the period up to 31 December 2021.

FFG is aware that Arsanis Inc. has entered in an option and license agreement with subsidiaries of Bravos Biosciences, LLC for the ASN200 and ASN300 programs and confirms that this licensing (as disclosed to FFG) does not constitute a violation of the above-mentioned obligation or any other obligation between Arsanis AT, Arsanis Inc. and FFG, including under the Subsidy Agreements.

FFG was informed by Arsanis AT by way of final report regarding the ASN400 project (submitted to FFG by Arsanis AT on 1 March 2018) that Arsanis AT has abandoned the respective project and confirms the abandonment does not constitute a violation of the above-mentioned obligation or any other obligation, including under the Subsidy Agreements.

Further, FFG was informed by Arsanis AT that Arsanis AT has discontinued its Phase 2 clinical trial of ASN100 for the prevention of S. aureus pneumonia in high-risk, mechanically ventilated patients and confirms that such action does not constitute a violation of the above-mentioned obligation or any other obligation, including under the Subsidy Agreements.

Arsanis AT shall provide FFG with a bank account excerpt, balance sheet and statement of operations (P&L statement) of Arsanis AT (each dated as of the end of the respective calendar quarter) on a quarterly basis. The bank account excerpt shall be sent within five (5) days after the end of the respective calendar quarter, and the other above reports shall be sent to FFG within five (5) days after Arsanis Inc. files its required quarterly and annual reports on Forms 10-Q and 10-K, respectively, with the United States Securities and Exchange Commission.

In case of a failure of Arsanis AT to deliver any of the bank account excerpts or any of the reports according to the foregoing paragraph, FFG shall provide Arsanis AT with a reminder giving Arsanis AT a minimum fourteen (14) day grace period to provide such excerpts or reports. A copy of such letter shall be sent to Arsanis Inc.

Arsanis Inc. shall procure the timely transfer of sufficient funds to Arsanis AT in order to enable Arsanis AT to ensure the minimum cash balance requirement in accordance with Section 3.3 of this Agreement can be met by Arsanis AT at any given time.

Arsanis Inc shall use its best efforts to enable Arsanis AT to comply with the obligations provided for under Section 3.1 to 3.6 of this Agreement and shall refrain from any instructions and measures that might endanger such compliance.

Artemis and X4 confirm that they are aware of the obligations and commitments of Arsanis AT and Arsanis Inc. provided for under Section 3.1 to 3.7 of this Agreement. Each of them shall use commercially reasonable efforts to enable Arsanis AT and Arsanis Inc. to comply with their obligations provided for under Section 3.1 to 3.7 of this Agreement, which will not include actions that cause a breach or event of default under X4’s existing loan facilities, and shall refrain from any instructions and measures that might endanger such compliance.

In the event of a breach (respectively a continuing breach despite the granting and the lapse of a grace period if and where a grace period is expressly foreseen under this Agreement) by Arsanis AT and/or Arsanis Inc. of any of the obligations, commitments and undertakings stipulated in Section 3.1 to 3.5, with respect to Section 3.6 only as far as it is related to the bank account excerpts and with regard to the first paragraph of Section 3.7 of this Agreement, FFG shall be entitled to declare any of the outstanding loan repayments as stipulated under Section 3.1 or parts thereof due for immediate repayment.

Any further rights FFG might have under any of the Subsidy Agreements remain unaffected.

Except for the claims for repayment of the loans and regular interest according to the payment schedule under Section 3.1 and Section 3.2 of this Agreement, FFG waives all claims against Arsanis AT and Arsanis Inc., including those set forth in the letters described in Section 2.6, in particular any claims for repayment of grants and interest exceeding such regular interest, under the suspensive condition and provided that Arsanis AT and Arsanis Inc. comply with the obligations and commitments according to Sections 3.1 to 3.7 of this Agreement. FFG will not pursue such claims as long as an Event of Default according to Section 3.9 of this Agreement has not occurred.

Subject to the fulfillment of Arsanis AT’s obligations and commitments according to Sections 3.1 to 3.5 of this Agreement, FFG releases with effect as of 31 December 2021 (i) Arsanis AT from all obligations and claims arising from and in relation to the Subsidy Agreements, (ii) Arsanis Inc. from all obligations vis-a-vis FGG and claims of FFG arising from and in relation to Arsanis, Inc.’s commitments provided under this Agreement and provided for under any other documents in favor of Arsanis AT in effect as of the date of this Agreement and (iii) Artemis and X4 from all obligations and claims arising from and in relation to their commitments provided under this Agreement.

Arsanis AT shall not be entitled to any further payouts of loans and grants under the existing Subsidy Agreements.

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