Privacy Policy

X4 Pharmaceuticals, Inc. and its subsidiaries recognize the importance of protecting your privacy. This Privacy Policy (Policy) discloses our information-gathering and dissemination practices for this website at

By using this Website, you agree to be bound by the terms and conditions of this Policy and the Terms of Use. If you do not agree with the terms of this Policy or the Terms of Use, or other terms and conditions on this Website, then do not use this Website. Based upon your specific relationship(s) with X4 Pharmaceuticals, Inc., we may collect, use, or disclose Personal Information (defined below) in ways described in more detail in one or more Other Agreements. To the extent the Other Agreement includes additional terms that are not covered by or are inconsistent with this Policy, the terms and conditions of the Other Agreement will supersede this Policy.

Within this Policy you will find covered matters related to the following:

Information We Collect
How We Use Your Personal Information
Disclosure of Your Personal Information
Choice to Opt-Out and Access to Your Information
Links to Third Party Sites
Governing Law and Jurisdiction
California Privacy Rights
Logging Practices
Do Not Track
Contact Information

This Website is not directed at children and we do not knowingly collect Personal Information (as defined below) online from children under the age of 13. If we learn that we have received Personal Information from a child under the age of 13, we will delete it. If you learn that your child has provided us with personal information without your consent, you may contact us as set forth below.


Personal Information

We collect and store Personal Information that you provide voluntarily when using this Website. Personal Information is defined as information that can identify you as a specific individual. You are responsible for providing accurate and complete information. For example, you might provide us the following information: information requests,  responses and survey information, site registrations, or web portal registration information. Personal Information does not include anonymized aggregate or statistical information from which such identification cannot be reconstituted.

If you request one of our services, we may collect the following Personal Information: full name, home address, e-mail address, telephone number, employment history, and your answers to other similar background information questions, and how you specifically use this Website.

Other Information

When you visit any page on this Website, we use a program that monitors and evaluates this Website’s traffic. It automatically records every visitor’s host, domain name, pages visited, length of user session, browser type and/or IP address. We use this information to find out how many people visit this Website to determine the areas of greatest interest on this Website, and to make improvements to this Website.

When you visit and interact with this Website, X4 Pharmaceuticals, Inc., and third parties with whom X4 Pharmaceuticals, Inc., has contracted to provide services to us, may collect non-personal information (for example, a catalog of the site pages you visit, or your IP address).


As with many other sites, this Website may use cookies or other technologies to help us deliver content specific to your interests, to process your inquiries or requests, and/or to analyze your visiting patterns. Cookies, by themselves, will not be used by X4 Pharmaceuticals, Inc., to disclose your individual identity. This information identifies your browser, but not you, to our servers when you visit this Website. If you want to disable the use of cookies or remove them at any time from your computer, you can disable or delete them using your browser (consult your browser’s help menu to learn how to delete cookies), however, you must enable cookies to access certain information on this Website. Note that in limited instances, such as when you create an online account, or request one of our other services, cookies may contain and be associated with the Personal Information we collect.


We may use your Personal Information to:

  • Complete any registration that you request online;
  • Publish your Personal Information on our website if you consent or opt-in to us sharing it;
  • Improve this Website;
  • Improve our products and services, and identify, develop, and offer new or expanded products and services;
  • Personalize your experience on this Website, and customize the content and/or format of the pages you visit;
  • Share information with you, if you opt-in to receive updates from us;
  • Ask you to participate in brief surveys; and/or
  • Generate aggregate statistical studies and conduct research related to our products and services and the use of this Website.

Based upon your specific relationship(s) with X4 Pharmaceuticals, Inc., we may use your Personal Information in ways described in more detail in one or more Other Agreements. In some instances, we may combine your Personal Information with other information (such as embedding e-mail addresses in cookies). If we do combine any non-personal information with Personal Information, the combined information will be treated by us as Personal Information in accordance with this Policy.


We disclose your Personal Information to certain third parties with whom we have a direct or indirect business or contract relationship.  When you request our services, we will provide your personal data to third parties with whom we arrange for those services to be provided. We may also disclose information to third parties that provide administrative or processing services for us, for example, printing or mailing.  Once these third-party service providers receive your Personal Information from us, their use of that information to provide services to you subject to the terms of use and privacy policies of those third parties.

We may also disclose Personal Information collected on this Website, in accordance with applicable law, to assert or defend our rights and property, to prevent harm to others, to collect a debt, or in response to legal processes such as subpoenas. We may also provide (or reserve the right to provide) Personal Information to credit reporting agencies and to cooperate with law enforcement authorities and other governmental authorities consistent with applicable laws.

If you have specifically consented to our doing so, we may also share your personal data with third parties in order that they may offer you information about their goods and services.

Based upon your specific relationship(s) with X4 Pharmaceuticals, Inc., we may disclose your Personal Information in ways described in more detail in one or more Other Agreements.


This Website may contain links to other third party websites. X4 Pharmaceuticals, Inc., does not control the privacy policies or practices of these third-party sites. You should review those policies before providing any information. X4 Pharmaceuticals, Inc., is not responsible for the content or practices of any linked third-party sites, and we provide these links solely for the convenience and information of our visitors.


X4 Pharmaceuticals, Inc., has established safeguards to help prevent unauthorized access to or misuse of your Personal Information, but cannot guarantee that your Personal Information will never be disclosed in a manner inconsistent with this Policy (for example, as a result of unauthorized acts by third parties that violate applicable law or relevant Web policies). If we become aware of a breach of your Personal Information either by us or by third-party(s) working on our behalf, we will make every reasonable attempt to notify you within 48 hours.


X4 Pharmaceuticals, Inc., reserves the right to change this Policy to respond to new laws, regulations, technology, or for other business reasons. Please check this Website from time to time to review any such changes. Using this Website following the posting of changes to this Policy shall constitute your acceptance of the revised Policy.


You agree that any claim, action or proceeding arising out of this Policy, or your use of this Website, shall be governed by and construed in accordance with the laws of the United States and the Commonwealth of Massachusetts, without regard to principles of conflict of laws. Any claim, action or proceeding related to this Policy will be resolved exclusively in the state or federal courts located in the Commonwealth of Massachusetts and you consent to the jurisdiction of those courts.


California law permits users who are California residents to request and obtain from us once a year, free of charge, a list of the third parties to whom we have disclosed their personal information (if any) for their direct marketing purposes in the prior calendar year, as well as the type of personal information disclosed to those parties. Except as otherwise provided in this Privacy Policy, X4 Pharmaceuticals, Inc., does not share personal information with third parties for their own marketing purposes.


Although our website may log information pertaining to system performance and other information relevant to improving the user experience, we will not log sensitive information. Sensitive information may include personally identifiable information, session identifiers that the user has opted out of, or authorization tokens.


Although our Website currently does not have a mechanism to recognize the various web browser Do Not Track signals, we do offer you choices to manage your preferences as described in the sections above. To learn more about browser tracking signals and Do Not Track please visit:


If you have any questions or concerns about this Website or security policies, you may contact us at 857-529-8300 or write to us in care of:

61 North Beacon Street, 4th Floor
Boston, MA 02134

This Privacy Policy is effective as of April 1, 2021