INBRX-101 has a favorable safety profile in patients with alpha-1 antitrypsin deficiency and demonstrates the potential to achieve normal functional levels of alpha-1 antitrypsin with monthly administration


Data from this multi-country phase 1 study come from 31 patients with AATD: 26 with genotype ZZ, 3 with genotype SZ and 2 with genotype MZ of the SERPINA1 gene, the underlying cause of AATD . The treatment was well tolerated with no serious or serious adverse events related to the study drug. Drug-related adverse events were mostly mild, and the few events of moderate severity were all transient and reversible, with minimal or no symptomatic care. No evidence of neutralizing anti-drug antibodies related to safety or PK/PD was observed.

Dose-related increases in maximum and total exposure to INBRX-101 occurred throughout the single and multiple ascending dose ranges.

Data from multiple escalating dose cohorts of INBRX-101 at 40, 80, and 120 mg/kg IV every three weeks showed the expected accumulation of functional AAT levels. Based on pharmacokinetic modeling, accumulation should continue after subsequent doses and reach a steady state after a total of approximately five to six consecutive doses, administered every three weeks.

The current standard of care, plasma-derived AAT, dosed once weekly at 60 mg/kg, achieves a Cmean functional AAT of 17.8 µM over the weekly dosing interval, calculated from steady-state area under the curve (“AUC”) values ​​reported in Stocks et al. BMC Clinical Pharmacology 2010, 10:13. INBRX-101 achieved a medium Cmean functional AAT of 40.4 µM over the 21-day dosing interval following the third 80 mg/kg dose.

To date, bronchoalveolar lavage fluid samples have been processed from two individuals in the 80 mg/kg multiple dose cohort and confirm the presence of INBRX-101 in lung fluid.

Additionally, functional AAT levels were measured in plasma samples from 65 normal MM genotype individuals. This analysis revealed the 5and and 95and the percentiles of functional AAT levels in individuals with the normal MM genotype were 23 and 57 µM, respectively, with a median of 38 µM.

“We believe these data demonstrate the potential of INBRX-101 to change the paradigm of treatment for AAT deficiency by maintaining patients within the normal range of functional AAT while reducing infusions from 52 per year to as few as 12 per year. We look forward to working with regulators, clinicians and patients to accelerate this therapy to AAT-deficient patients as quickly as possible,” said Marc LappeCEO of Inhibrx.

The Company will host a live web presentation today, May 16andto 1:30 p.m. PT to discuss the results further.

About the conference call

Investors can join via web: or can listen to the call by dialing (1-888-220-8451). Please refer to Inhibrx, Inc. or confirmation code 2516861 when calling. After the webcast, the presentation can be viewed via a link in the investors section of Inhibrx’s website at The webcast will be available for 60 days after the event. Following the presentation, Inhibrx will update its corporate presentation in the “Investors” section of its website at

About INBRX-101 and AATD

INBRX-101 is a precision-engineered recombinant human AAT-Fc fusion protein designed to safely achieve and maintain the levels of AAT found in healthy individuals with the potential for monthly administration.

AATD is an inherited orphan disease affecting approximately 100,000 patients in United States. AATD is characterized by deficient levels of the AAT protein, which leads to loss of lung tissue and function and decreased life expectancy. Plasma-derived AAT is the current standard of care and does not keep patients within the normal AAT range, requires frequent and inconvenient once-weekly intravenous administration, and relies on plasma collection practices that may not not be durable.

About Inhibrx, Inc.

Inhibrx is a clinical-stage biotechnology company focused on developing a broad portfolio of novel biologic therapeutic candidates in oncology and orphan diseases. Inhibrx uses various protein engineering methods to address the specific requirements of complex target and disease biology, including its proprietary sdAb platform. Inhibrx has collaborations with 2seventy bio (formerly bluebird bio), Bristol-Myers Squibb and Chiesi. For more information, please visit

Forward-looking statements

Inhibrx cautions you that statements included in this press release regarding matters that are not historical facts are forward-looking statements. These statements are based on current beliefs and expectations of Inhibrx. Such statements include, without limitation, statements regarding: the judgments and convictions Inhibrx and its researchers on the safety and efficacy observed to date of its therapeutic candidate, the INBRX-101 , discussions and beliefs concerning future actions of the US Food and Drug Administration, statements and beliefs regarding the current standard of care for the AAT and the sustainability of current practices of plasma collection and the potential for INBRX-101 change the standard of care, the future clinical development, application and dosage of INBRX-101 and the presumption that the main data will be representative of the final data and PK modeling is an accurate predictor of PK levels on a basis wider. Actual results may differ from those presented in this press release due to the risks and uncertainties inherent in Inhibrx activities, including, without limitation, risks and uncertainties regarding the launch, timing, progress and the results of preclinical studies and clinical trials, and research and development programs; its ability to advance therapeutic candidates into clinical trials and to carry them out; its interpretation of the initial data, intermediate and preliminary clinical trials, including interpretations concerning the control of the disease and the response to the disease; the timing or likelihood of deposits and regulatory approvals; the successful commercialization of its drug candidates, if approved; pricing, coverage and reimbursement of therapeutic candidates, if approved; ability to use its technology platform to generate and advance additional drug candidates; implementation of its business model and strategic plans for its commercial and therapeutic candidates; ability to successfully manufacture therapeutic candidates in clinical trials and commercial use, if approved; its ability to enter into contracts with suppliers and third-party manufacturers and their ability to function adequately; the extent of the protection it is able to establish and maintain for intellectual property rights covering its drug candidates; its ability to form strategic partnerships and potential benefits of such partnerships; its estimates of expenses, capital requirements and additional funding requirements and financial performance; expectations regarding the impact of the pandemic Covid-19 on its business; and other risks described in the documents filed by Inhibrx with the Securities and Exchange Commission of the United States (the “SEC”), including under the heading “Risk Factors” in the Annual Report on Form 10 Inhibrx -K for the year ended December 31, 2021, as filed with the SEC on February 28, 2022, as well as its quarterly reports on Form 10-Q, and supplemented from time to time by its current reports on Form 8-K. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Inhibrx undertakes no obligation to update these statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. This press release contains estimates and other statistical data made by independent parties and by Inhibrx. These data involve a number of assumptions and limitations, and you are cautioned not to place undue weight on these estimates.

Investor and media contact:
Kelly DeckCFO
[email protected]

SOURCEInhibrx Inc.


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