NeurogesX announced it has received an additional notice of allowance from the U.S. Patent and Trademark Office, or USPTO, related to the company's family of patents for NGX-1998, the company's next generation liquid formulation of prescription-strength capsaicin. The allowed patent application expands on the company's patent entitled, "Methods and compositions for administration of TRPV1 agonists." The claims in the allowed application relate to methods of treating capsaicin-responsive conditions with a liquid formulation containing between 10% and 30% by weight of a TRPV1 agonist and certain penetration enhancer combinations. The capsaicin-responsive conditions referenced in the patent application include various types of pain, such as neuropathic pain and pain associated with skin cancer. The patent issuing from this application is expected to expire in 2024.