Adolore BioTherapeutics Receives FDA Orphan Drug Designation for Gene Therapy Targeting Erythromelalgia
Key Insights
Adolore BioTherapeutics (search) received FDA Orphan Drug Designation for its rdHSV-CA8* (search) gene therapy to treat erythromelalgia (search), a rare genetic pain disorder affecting approximately 50,000 U.S. patients.
The Kv7 (search) voltage-gated potassium channel activating therapy demonstrated equipotent analgesia to opioids in preclinical studies without opioid-related side effects.
The designation provides up to seven years of market exclusivity upon FDA approval and may enable expedited development pathways for faster patient access.
Adolore BioTherapeutics (search) announced that the FDA Office of Orphan Products Development has approved an Orphan Drug Designation (ODD) for its innovative Kv7 (search) activating rdHSV-CA8* (search) gene therapy for the treatment of primary and secondary erythromelalgia (search) (EM). The designation applies to approximately 50,000 patients in the United States who suffer from severe chronic pain (search) due to hereditary neuronal sodium ion channel mutations.
Novel Gene Therapy Approach
The company's rdHSV-CA8* (search) therapy represents a breakthrough approach to treating erythromelalgia (search) by targeting the underlying molecular mechanism of the disease. In primary EM, gain-of-function mutations in the SCN9A (search) gene encoding for the Nav1.7 sodium channel cause these channels to become more easily activated, leading to hyperexcitability in pain sensing neurons. Adolore's CA8* gene therapy activates Kv7 (search) channels, which can reverse this hyperexcitability and target the root cause of EM.
"Approval of this ODD underscores the importance of treating EM and recognizes the rationale for treatment with our novel approach," commented Roelof Rongen, CEO of Adolore. "Upon FDA approval, Adolore may be eligible for up to seven years of U.S. market exclusivity for this indication, along with other development incentives available under the Orphan Drug Act."
Preclinical Efficacy and Safety Profile
Preclinical studies have demonstrated that Adolore's Kv7 (search) voltage-gated potassium channel activating rdHSV-CA8* (search) therapy is equipotent to opioid-induced analgesia. The therapy produces profound long-lived analgesia without any opioid-related side effects, addressing a critical unmet medical need in pain management.
"Adolore has generated compelling safety, biodistribution, shedding, histology, and clinical safety data; as well as substantial preclinical efficacy data for its localized rdHSV-CA8* (search) gene therapy," said Roy Clifford Levitt, MD, pain physician, inventor and founder/chairman of Adolore. "These largely published data demonstrate Kv7 (search) voltage-gated potassium channel activation by a single dose of rdHSV-CA8* gene therapy, reversal of neuronal hyperexcitability, and the production of profound long-lived analgesia."
Addressing Significant Unmet Medical Need
Currently, there is no FDA-approved therapy specifically for erythromelalgia (search). Existing treatments target EM symptoms but are largely ineffective, leaving patients with debilitating pain. EM patients typically experience severe burning pain, redness, heat and sometimes swelling during attacks that can last minutes to hours and are triggered by minimal stressors including heat, exercise, wearing warm socks or tight shoes, and alcohol consumption.
"Adolore's gene therapy could address EM patients' significant and unmet medical need because there is no FDA approved therapy," Levitt noted. "Existing therapies target EM symptoms but are largely ineffective, leaving EM patients with debilitating pain."
Genetic Validation of Therapeutic Approach
Further validation of Adolore's approach comes from human genetic studies of EM families, which show that concurrent activating mutations of Kv7 (search)-potassium channels can overcome the severe chronic pain (search) caused by neuronal Nav1.7 sodium channel mutations. This genetic evidence supports the therapeutic rationale for activating Kv7 channels to treat erythromelalgia (search).
Strategic Development Programs
The ODD approval provides additional rationale and momentum for Adolore's rdHSV-CA8* (search) gene therapy development. The company is currently advancing two preclinical development programs leveraging its innovative gene therapy platform. The lead program for chronic pain (search) due to knee osteoarthritis is funded by a UG3/UH3 grant from the NIH/NINDS/HEAL Program, with a first-in-human study expected to commence in 2027.
Development of the rdHSV-CA8* (search) gene therapy in EM is of strategic importance as it creates an additional path to treating patients with high unmet need and may support future consideration of expedited development and review pathways, potentially enabling faster patient access and product commercialization.