PharmaSonics Inc has been issued four additional U.S. patents and has received a notice of allowance for four other patent applications. The issued and allowed patents provide the coverage needed to continue the development efforts of Sonotherapy into new and emerging markets such as hemodialysis and drug-gene delivery. This issuance expands to 14 the total number of U.S. patents issued to PharmaSonics. Issuance of a patent confirms ownership, while a notice of allowance is a pre-announcement of a pending patent issuance.
Of note is the issued patent that covers the application of the Sonotherapy treatment of arterio-venous grafts and fistulas, which are commonly used for vascular access in hemodialysis patients (U.S. patent 6,387,116). To undergo kidney dialysis, a patient has surgically placed a graft or fistula, which provides the vascular access to facilitate the dialysis treatment. Sonotherapy has undergone pre-clinical investigation to prevent restenosis in these vascular grafts and fistulas.
Grafts and fistulas, when used in hemodialysis patients, can require revascularization up to 3 times per year. In 1999, Medicare spent $2.8 billion for vascular access-related hospitalization in the U.S. In 1999, the company estimates that there were 964,000 dialysis patients worldwide. The company estimates this number to grow to 1,346,000 patients worldwide in 2003, a 7% CAGR.
Allowed under U.S. patent 6,372,498 is the use of Sonotherapy to enhance the transfection of vascular smooth muscle cells by combining gene delivery with Sonotherapy. Ultrasound has been shown to increase membrane permeability and facilitate diffusion of therapeutic agents such as drugs, nucleic acid, and genetic matter into tissue. Combining Sonotherapy with gene delivery can enhance the efficacy of gene expression, reduce dosing needs and allow for a broader use of gene therapeutic agents with non-viral vectors.
During the Trans-Catheter Therapeutics (TCT) 2002 meeting, a presentation summarizing pre-clinical work recently done at the University of Sheffield, U.K., will show a fourfold increase in drug (DNA) uptake by vascular smooth muscle cells with Intravascular Sonotherapy enhanced drug-delivery of drug-eluting stents, compared to sham controls, which consisted of drug-eluting stents alone. The presentation (# 300) will take place on September 25th in the Washington Convention Center, Washington D.C.
Menahem Nassi, PharmaSonics President and CEO, stated, "Receiving these new patents strengthens our ability to protect and position PharmaSonics'''' leadership in new markets for Sonotherapy like the anti-restenosis market for hemodialysis vascular access, and the delivery of therapeutic agents such as genes and drugs. In addition, PharmaSonics is building its intellectual property portfolio to expand the application of Sonotherapy for the treatment of vulnerable plaque and use with drug-eluting stents."
The Sonotherapy trial, SWING, aims at establishing the nine-month safety and efficacy of Sonotherapy in reducing the incidence of restenosis in coronary de novo stented patients. SWING is a worldwide 1,200-patient, prospective, double blind, randomized study. Patients were enrolled from Europe, U.S., Canada and South America. The results will be released on November 18 at the American Heart Association Meeting by the principal investigator, Richard E.Kuntz.