Inozyme Pharma, Inc. announced positive interim safety, pharmacokinetic (PK), pharmacodynamic (PD) and exploratory efficacy data from the Company?s ongoing Phase 1/2 clinical trials of INZ-701 in adults with ENPP1 Deficiency and ABCC6 Deficiency (PXE, pseudoxanthoma elasticum). ENPP1 Deficiency: Nine patients were initially enrolled in the ongoing Phase 1/2 clinical trial across three dose cohorts of INZ-701 (0.2 mg/kg (n=3), 0.6 mg/kg (n=3), and 1.8 mg/kg (n=3)). For trial design details, please see the section entitled ?INZ-701 in ENPP1 Deficiency Phase 1/2 Clinical Trial Design?

below. Exploratory Biomarker Data: Exploratory biomarker data were collected throughout the study to provide evidence of the potential for disease modification with ongoing treatment with INZ-701. Notable changes in key biomarkers were observed and support the clinical hypothesis, including: Meaningful reduction of fibroblast growth factor-23 (FGF-23) observed.

Most patients with ENPP1 Deficiency have elevated levels of FGF-23, which leads to increased phosphate wasting and hypophosphatemia, a key driver of osteomalacia and rickets; Serum phosphate (Pi) levels increased over time, in the absence of phosphate and active vitamin D supplementation, which were withheld from patients during the study; Statistically significant correlation between increase in plasma pyrophosphate (PPi) and decrease in FGF-23 observed at one week post first dose; Upward trends observed in bone specific alkaline phosphatase (BSAP) levels from baseline, which signal biological activity in bone tissue. Exploratory Efficacy Data: Outcome measures were collected to assess potential clinical benefit with ongoing treatment with INZ-701 and to inform the design and patient selection of future trials in adolescents and adults. Notable changes in PROs and functional outcomes were observed in all cohorts, including: Concordant improvement in GIC scores reported by patients (P-GIC) and clinicians (C-GIC), and no patient showed a deterioration from baseline.

High responder rates in Patient-Reported Outcome Measurement Information Scales (PROMIS) of Pain Intensity, Fatigue and Pain Interference; Trend of improvement in 6-minute walk test (6-MWT). Subgroup analysis of 6-MWT results showed greater improvement in patients with lower baseline values and stable results over time in patients with higher baseline values; Subgroup analysis of patients who presented with arthritis/arthralgia at baseline showed improvement in 6-MWT, and increased spine bone mineral density (BMD) and bone mineral content (BMC), as measured by dual x-ray absorptiometry (DEXA). Pharmacodynamic (PD) and Pharmacokinetic (PK) Data: Rapid, significant, and sustained increase in PPi levels observed in all patients and significant elevation in PPi maintained for up to 18 months; Long half-life of approximately 126 hours and drug accumulation as shown by a greater than dose proportional exposure suggests the potential for once weekly dosing.