Sanofi's Acquired Drug Shows Promise in Rare Disease Trial, Validating Inhibrx Buyout

French pharmaceutical giant Sanofi has announced positive results from a Phase 2 study of efdoralprin alfa, an experimental drug for alpha-1 antitrypsin deficiency (AATD), a rare genetic condition affecting the liver and lungs. The success of this trial not only represents a significant step forward in AATD treatment but also validates Sanofi's $2.2 billion acquisition of Inhibrx in 2024.

Efdoralprin Alfa: A New Approach to AATD Treatment

Efdoralprin alfa, a recombinant protein designed to block an enzyme involved in inflammation and lung tissue damage, has shown promising results in treating AATD emphysema. The drug met all primary and key secondary endpoints in the Phase 2 study, demonstrating superiority over current plasma-derived therapies in several crucial areas:

• Higher increases in protective AAT protein levels compared to weekly plasma-derived therapy infusions
• Greater concentration of functional protein in the bloodstream
• More days above the "lower limit" of normal AAT levels

Importantly, the drug maintained a safety profile similar to that of plasma therapy while offering the potential for less frequent dosing. Patients received efdoralprin alfa every three or four weeks, compared to the weekly infusions required for current treatments.

Implications for AATD Patients and the Pharmaceutical Industry

AATD affects approximately 235,000 people globally, with 100,000 cases in the United States alone. However, Sanofi reports that 90% of these cases remain undiagnosed, highlighting a significant unmet medical need and potential market opportunity.

Dr. Igor Barjaktarevic, a study investigator and associate professor at the David Geffen School of Medicine at UCLA, emphasized the potential impact of efdoralprin alfa: "Achieving and maintaining normal AAT levels with less frequent dosing and with complete independence from blood donation programs would be a welcome change to the current treatment experience for people living with AATD."

The success of efdoralprin alfa could represent a major shift in AATD treatment, offering patients a more convenient and potentially more effective option. For Sanofi, the positive trial results support their strategic decision to acquire Inhibrx and expand their rare disease portfolio.

Market Implications and Future Outlook

Leerink Partners analyst David Risinger noted that the trial results "validate" Sanofi's acquisition of Inhibrx and could provide "significant upward pressure" on consensus estimates for the drug. The sizable patient population, coupled with the high rate of undiagnosed cases, presents a substantial commercial opportunity for Sanofi.

As the company prepares to present detailed data at an upcoming medical meeting and engage with global regulatory authorities, the pharmaceutical industry will be watching closely. Efdoralprin alfa's success could potentially reshape the competitive landscape in AATD treatment, where several companies are developing alternative approaches, including RNA editing, gene editing, and RNA interference therapies.