Inhibrx Incorporated announced favorable initial results of its phase 1 clinical trial on the safety, pharmacokinetics, and pharmacodynamics of the optimized recombinant human alpha-1 antitrypsin (AAT)-Fc protein therapy INBRX-101 for patients with alpha-1 antitrypsin deficiency (AATD).

The results, announced via news release, showed favorable safety and tolerability, and no drug-related severe or serious adverse events.

“We believe this data demonstrates the potential of INBRX-101 to change the paradigm of treatment of AAT deficiency by maintaining patients in the normal range of functional AAT while reducing infusions from 52 annually to as few as 12 annually,” Mark Lappe, chief executive officer of Inhibrx, said.

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“We look forward to working with regulators, clinicians, and patients to expedite this therapy to AAT deficient patients as rapidly as possible.”

INBRX-101 is an engineered recombinant human AAT-Fc fusion protein aimed at restoring and maintaining healthy levels of ATT in patients with AATD with once-per-month dosing.

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The current trial included multiple ascending dose cohorts of 40 mg/kg, 80 mg/kg, and 120 mg/kg intravenously every 3 weeks. Following the third 80 mg/kg dose, the average functional AAT level achieved over the 21-day period was 40.4 micromolar.

This achievement represents a significant improvement over the current standard of care, which employs plasma-derived AAT dosed at 60 mg/kg weekly and results in an average AAT level of just 17.8, well below the normal range.

The treatment was well tolerated and the few drug-related adverse events that occurred were mild, transient, and reversible. No neutralizing antidrug antibodies were observed.


Inbrx-101 shows favorable safety profile in patients with alpha-1 antitrypsin deficiency and demonstrates potential to achieve normal functional alpha-1 antitrypsin levels with monthly dosing. New release. Inhibrx Incorporated; May 16, 2022.