— Interim results from the Phase 1 study show a favorable safety and tolerability profile with no drug-related severe or serious adverse events at doses up to and including 120 mg/kg single dose and 80mg/kg multi-dose administered intravenously, or IV.

— Data from the single ascending dose cohorts at 10, 40, 80 and 120 mg/kg revealed the potential to achieve normal AAT levels with monthly dosing.

— Data from the first multiple ascending dose cohort at 40 mg/kg IV every three weeks showed the expected accumulation of functional AAT levels with observed trough levels exceeding those achieved by the current standard of care.

SAN DIEGO, CA, USA I October 12, 2021 I Inhibrx, Inc. (Nasdaq: INBX), a biotechnology company with four clinical programs in development and an emerging pre-clinical pipeline, today announced interim results from a Phase 1 clinical trial evaluating the safety and pharmacokinetics of INBRX-101, an optimized recombinant human AAT-Fc fusion protein, in patients with alpha-1 antitrypsin deficiency, or AATD.

Interim functional PK data from this multi-country multi-center Phase 1 study are from 21 patients with AATD, all with the ZZ mutation of the SERPINA1 gene, the underlying cause of AATD. Interim safety data are from 24 patients with AATD. There were no drug-related severe or serious adverse events at doses up to and including 120 mg/kg single dose and 80mg/kg multi-dose. Drug-related adverse events were predominantly mild with a few moderate events and all were transient and reversible. No signs of neutralizing anti-drug antibodies have been seen.

Dose related increases in maximal and total INBRX-101 exposure occurred across the entirety of the tested single ascending dose range of 10 to 120 mg/kg.

Data from the first multiple ascending dose cohort of INBRX-101 at 40 mg/kg IV every three weeks showed the expected accumulation of functional alpha-1 antitrypsin, or AAT, levels with observed trough levels exceeding the goal of the current standard augmentation therapy with plasma-derived AAT.

Functional AAT and bronchoalveolar lavage data from patients to be administered three INBRX-101 doses of 80 or 120 mg/kg IV every three weeks are expected in the first half of 2022.

“These initial data demonstrate the potential of INBRX-101 to significantly improve treatment for patients with AATD by maintaining them in the normal range of functional AAT and reducing infusions from 52 annually to possibly as few as 12 annually,” said Mark Lappe, CEO of Inhibrx.

The Company will host a live webcast presentation today at 5:30 a.m. PT to further discuss the results.

About the Conference Call

Investors may join via the web: https://www.webcaster4.com/Webcast/Page/2560/43178 or may listen to the call by dialing (1-877-870-4263) from locations in the United States or (1-412-317-0790) from outside the United States. Please refer to Inhibrx, Inc. when calling in. Following the webcast, the presentation may be accessed through a link on the “Investors” section of Inhibrx’s website at https://inhibrx.investorroom.com/events-and-presentations. The webcast will be available for 60 days following the event. Following the presentation, Inhibrx will update its corporate presentation within the “Investors” section of its website at www.inhibrx.com.

About INBRX-101 and AATD

INBRX-101 is a precisely engineered recombinant human AAT-Fc fusion protein designed to safely achieve and maintain levels of alpha-1 antitrypsin, or AAT, found in healthy individuals with the potential for once-monthly dosing.

Alpha-1 antitrypsin deficiency, or AATD, is an inherited orphan disease affecting an estimated 100,000 patients in the United States. AATD is characterized by deficient levels of the AAT protein, which causes loss of lung tissue and function and decreased life expectancy.  Plasma-derived AAT is the current standard of care and does not maintain patients in the normal AAT range, requires frequent and inconvenient once-weekly IV dosing, and relies on plasma collection practices that might not be sustainable. 

About Inhibrx, Inc.

Inhibrx is a clinical-stage biotechnology company focused on developing a broad pipeline of novel biologic therapeutic candidates in oncology and orphan diseases. Inhibrx utilizes diverse methods of protein engineering to address the specific requirements of complex target and disease biology, including its proprietary sdAb platform. Inhibrx has collaborations with bluebird bio, Bristol-Myers Squibb and Chiesi. For more information, please visit www.inhibrx.com.

SOURCE: Inhibrx