FDA Grants Fast Track Designation to Multiple Therapies for Rare Diseases and Hematologic Malignancies

The U.S. Food and Drug Administration has granted Fast Track Designation to QRX003 lotion (4%) for the treatment of Netherton Syndrome, a rare and severe genetic skin disorder for which there are currently no approved treatments. The designation was announced March 11, 2026, by Quoin Pharmaceuticals Ltd., a late clinical-stage specialty pharmaceutical company focused on developing and commercializing therapeutic products that treat rare and orphan diseases.

QRX003 lotion (4%) is currently being evaluated in two late-stage whole-body clinical trials designed to assess safety and efficacy in patients with Netherton Syndrome. QRX003 previously received Orphan Drug Designation from both the U.S. FDA and the European Medicines Agency (EMA) for the treatment of Netherton Syndrome, providing potential benefits including market exclusivity upon approval, tax credits for clinical testing, and certain regulatory fee reductions. QRX003 has also been granted Pediatric Rare Disease Designation by the FDA.

Netherton Syndrome is a rare, inherited skin disorder caused by mutations in the SPINK5 gene, leading to severe skin barrier dysfunction, chronic inflammation, and a heightened risk of infections and allergic complications. Patients often experience widespread skin redness, scaling, persistent itching, and significant impairment in quality of life. There are currently no FDA-approved therapies for the treatment of Netherton Syndrome, and treatment options are limited to supportive care and off-label therapies.

The FDA has also granted fast track designation to IBI3003, an investigational anti-GPRC5D/BCMA/CD3 trispecific antibody. This designation applies specifically to the treatment of relapsed/refractory multiple myeloma in patients who have received 4 or more prior lines of therapy, including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 monoclonal antibody. IBI3003 is designed to target both GPRC5D and BCMA to inhibit the tumor escape often associated with single-antigen targeting.

Clinical data from a phase 1/2 trial involving 39 patients demonstrated an overall response rate of 83.3% at doses of 120 μg/kg or higher. Notably, an 80% ORR was observed in patients with extramedullary disease, and a 77.8% ORR was recorded among patients with prior exposure to BCMA- or GPRC5D-directed therapies. For patients achieving a complete response or better, the minimal residual disease negativity rate was 100%.

From a safety perspective, cytokine release syndrome events were limited to grade 1 to 2, and only 2 cases of grade 1 to 2 immune effector cell-associated neurotoxicity syndrome were reported. Common treatment-emergent adverse events related to GPRC5D targeting included grade 1 to 2 effects on the skin, nails, and oral cavity.

IBI3003 has optimized CD3 affinity to ensure a balance between efficacy and safety. This approach aims to support effective engagement of T cells while preventing excessive activation of the immune system, which can cause cytokine release syndrome and immune-related reactions.

The FDA's Fast Track program is designed to facilitate the development and expedite the review of drugs that treat serious conditions and fill an unmet medical need. A therapy granted Fast Track Designation may benefit from more frequent interactions with the FDA, eligibility for rolling review of regulatory submissions, and potential qualification for Accelerated Approval and Priority Review, if relevant criteria are met.

In related regulatory actions, the FDA has accepted the new drug application for iberdomide used in combination with daratumumab and dexamethasone for patients with relapsed or refractory multiple myeloma. This application has been granted priority review and breakthrough therapy designation, with a target action date of August 17, 2026. Iberdomide is a potential first-in-class cereblon E3 ligase modulator agent. The regulatory filing is supported by the phase 3 EXCALIBER-RRMM study, which compares the oral IberDd regimen against the standard triplet of daratumumab, bortezomib, and dexamethasone. The study utilizes dual primary endpoints of MRD negativity and progression-free survival.

The FDA has also approved a label update for the CAR T-cell therapy axicabtagene ciloleucel, removing previous limitations of use for patients with relapsed or refractory primary central nervous system lymphoma. PCNSL is an aggressive form of non-Hodgkin lymphoma originating in the brain, spinal cord, eye, or cerebrospinal fluid. The prognosis for this condition is generally poor, with a 5-year survival rate of approximately 30%.