The purpose of this study (Study INZ701-304 [ADAPT]) is to assess the long-term safety of INZ-701 in patients with ENPP1 Deficiency or ABCC6 Deficiency who have received INZ-701 in an existing clinical study and choose to continue dosing for the potential treatment of their condition.

The investigational product INZ-701 is being developed as a therapeutic protein for the treatment of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) Deficiency and adenosine triphosphate (ATP)-binding cassette subfamily C member 6 (ABCC6) Deficiency. INZ-701 is a recombinant fusion protein that contains the extracellular domains of human ENPP1 coupled with an Fc fragment from an immunoglobulin (Ig) G1 antibody.

The ADAPT Study (INZ701-304) is an open-label study to assess the long-term safety of INZ-701 in patients with ENPP1 Deficiency or ABCC6 Deficiency who have received INZ-701 in an existing clinical study and choose to continue dosing for the potential treatment of their condition.

The study will consist of a 30-day Screening Period, followed by an open-label Treatment Period during which all participants will receive once-weekly subcutaneous (SC) doses of INZ-701 and continue with treatment until INZ-701 is commercially available in the country/region of the participant's residence or until Inozyme chooses to discontinue development of INZ-701. Participants will complete an End of Study (EOS) safety follow-up visit approximately 30 days after their last designated study visit assigned by the Investigator and/or Sponsor.

Individuals eligible to participate must meet all of the following inclusion criteria:

1. Provide written or electronic informed consent after the nature of the study has been explained, and prior to any research-related procedures, per International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Good Clinical Practice (GCP)
2. Provide assent in accordance with local regulations, if <18 years of age
3. Male or female, greater than 1 year of age
4. Must have completed the protocol-required safety and PK/PD and/or efficacy period(s) of a previous INZ-701 clinical study in ENPP1 or ABCC6 Deficiency, as confirmed by the Sponsor
5. Female participants of childbearing potential who are sexually active must be using or agree to use 1 highly effective form of contraception (per CTFG 2020) from at least 1 month before the first dose of INZ-701 through 30 days after last dose of INZ-701 (greater than 5 half-lives of INZ-701); participants must agree to not donate ova from the period following the first dose of INZ-701 through 30 days after the last dose of INZ-701
6. Male participants who are sexually active must agree to use condoms from the period following the first dose of INZ-701 through 30 days after the last dose of INZ-701; participants must agree to not donate sperm from the period following the first dose of INZ-701 through 30 days after last dose of INZ-701
7. In the opinion of the Investigator, able to complete all aspects of the study

Individuals who meet any of the following exclusion criteria will not be eligible to participate:

1. In the opinion of the Investigator, presence of any clinically significant disease or laboratory abnormality not associated with ENPP1 Deficiency or ABCC6 Deficiency, that will preclude study participation and/or may confound interpretation of study results
2. Known intolerance to INZ-701 or any of its excipients
3. Concurrent participation in another interventional clinical study and/or has received an investigational drug other than INZ-701 within 5 half-lives or within 4 weeks prior to the first dose of INZ-701 in this study, whichever is longer, or use of an investigational device
4. Pregnant, trying to become pregnant, or breastfeeding
5. Male participants trying to father a child