Knopp Biosciences Announces Publication of Phase 2 Trial Results of dexpramipexole in Hypereosinophilic Syndromes (HES) in Blood

A team of investigators led by Dr. Amy Klion at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), undertook the open-label study of dexpramipexole as a steroid-sparing agent in subjects with HES. Dexpramipexole had been observed to produce a significant, targeted reduction of peripheral blood eosinophils in earlier clinical trials in amyotrophic lateral sclerosis.

Subjects with HES on glucocorticoid therapy were eligible for the study if they required ≥10 mg prednisone or equivalent for control of symptoms and eosinophilia. Prior to study treatment, subjects underwent a standardized glucocorticoid taper to determine their minimally effective glucocorticoid dose (MED). Subjects for whom the MED had been determined within the past year or with an eosinophil count ≥1000/µL at the time of enrollment were eligible to proceed directly to dexpramipexole treatment at the discretion of the principal investigator. After 12 weeks of oral dexpramipexole treatment (150 mg twice daily) on a stable glucocorticoid dose, a glucocorticoid taper was attempted and the MED on dexpramipexole (MEDD) was determined.

The trial enrolled 10 subjects and met the co-primary endpoints of: 1) percentage of subjects experiencing a ≥50% reduction in MED and 2) reduction of glucocorticoid requirement among all subjects. Notably, three of the four responders meeting the primary endpoint exhibited complete hematological responses (eosinophil count of zero or near-zero) and were able to discontinue prednisone completely. These subjects have remained symptom-free, eosinophil-free, and steroid-free for 13-32 months while continuing dexpramipexole treatment, as reported in the article.

The investigators also reported that three of four responders who underwent biopsies had complete resolution of eosinophilia in affected skin or gastrointestinal tissue. Delayed and partial hematological responses were also noted in the trial.

Dexpramipexole was well tolerated, with no adverse events leading to drug interruption or discontinuation.

The article concluded, “Well-tolerated and with a dosing schedule convenient for routine outpatient treatment, dexpramipexole shows great promise as a novel oral therapy for HES.”

Michael Bozik, M.D., President and CEO of Knopp Biosciences, said, “The Blood publication demonstrates that dexpramipexole merits Phase 3 development in HES, a rare hematological disease with significant morbidity and limited treatment options. We are grateful for our collaboration with Dr. Klion and her NIH colleagues, and we look forward to initiating the Phase 3 study later this year.”

HES comprises a heterogeneous group of rare disorders characterized by peripheral eosinophilia and eosinophil-related end organ damage. The NIH trial enrolled subjects with the FIP1L1-PGDFRA-negative form of the disease, which accounts for 85-90% of all HES. Although glucocorticoid therapy is the first-line treatment for patients with FIP1L1-PGDFRA-negative HES, many patients develop serious side effects or resistance over time.

The Phase 2 study was conducted as part of an agreement between Knopp Biosciences and NIAID, demonstrating industry-government collaboration in the field of rare disease drug development.

ABOUT KNOPP BIOSCIENCES LLC

Knopp Biosciences, based in Pittsburgh, PA, USA, is a privately held drug discovery and development company focused on delivering breakthrough treatments for inflammatory and neurological diseases of high unmet need. Our clinical-stage small molecule, dexpramipexole, is entering Phase 3 development in hypereosinophilic syndromes and Phase 2 clinical development in eosinophilic asthma. Our preclinical platform is directed to small molecule treatments for neonatal epileptic encephalopathy, a devastating brain disorder of infants caused by a rare mutation in the KCNQ2 gene. Please visit knoppbio.com.

This press release contains “forward-looking statements,” including statements relating to planned regulatory filings and clinical development programs for dexpramipexole. All forward-looking statements are based on management’s current assumptions and expectations and involve risks, uncertainties and other important factors, specifically including the uncertainties inherent in clinical trials and product development programs, the availability of funding to support continued research and studies, the availability or potential availability of alternative therapies or treatments, the availability of patent protection for the discoveries and strategic alliances, as well as additional factors that may cause Knopp’s actual results to differ from our expectations. There can be no assurance that dexpramipexole will be successfully developed or manufactured or that final results of clinical studies will be supportive of regulatory approvals required to market the product. Knopp undertakes no obligation to update or revise any such forward-looking statements, whether as a result of new information, future events or otherwise.

Knopp’s pipeline consists of investigational drug products that have not been approved by the U.S. Food and Drug Administration. These investigational drug products are still undergoing clinical study to verify their safety and effectiveness.

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