Medical Device Daily Associate Managing Editor

Medtronic (Minneapolis) reported that the FDA has approved the company's InterStim II system for the treatment of intractable cases of overactive bladder and urinary retention. InterStim therapy for urinary control uses sacral nerve stimulation to improve bladder function.

Originally approved by the FDA in 1997, the device is indicated in the U.S. for the treatment of non-obstructive urinary retention and the symptoms of overactive bladder, including urinary urge incontinence and significant symptoms of urgency-frequency alone or in combination, when more conservative treatments fail or cause intolerable side-effects.

The new system also recently received the CE mark in Europe, where InterStim therapy is indicated for the management of chronic intractable (functional) disorders of the pelvis and lower urinary tract or intestinal tract, including overactive bladder, urinary retention, fecal incontinence, and constipation.

Enhancing the original InterStim INS device that was approved by the FDA in 1993 for urinary incontinence, the InterStim II system adds a new implantable neurostimulator (INS), a new improved patient programmer and upgraded software for the clinician programmer. The company said that these advancements offer a choice of neurostimulation devices to accommodate more patients, streamline the implant procedure, and simplify programming and follow-up care. The improved patient programmer also gives patients more control of their therapy, the company noted.

“This new smaller, lighter device – combined with the array of smart design changes to other components of the implantable system – will make InterStim therapy more attractive to both physicians and patients,“ said Steven Siegel, MD, director of Metropolitan Urologic Specialists' Center for Continence Care (St. Paul, Minnesota). “The new patient programmer and physician programmer software upgrade represent a significant step forward for this treatment option for overactive bladder and urinary retention. With all of these enhancements, InterStim therapy deserves a fresh look from physicians and patients alike.“

The company said that the InterStim II's new INS is ideally suited for patients with lower energy requirements or smaller bodies. Additionally, the InterStim II INS is nearly 50% smaller by displaced volume and nearly 50% lighter by weight than the original device – the InterStim INS, which Medtronic noted still continues to be available.

The company said the InterStim iCon patient programmer offers many new features to improve patient management for physicians and provide greater therapy control for patients. Patients can use the programmer to select from four available programs and adjust the stimulation amplitude (only) for each of them.

The InterStim iCon programmer offers these new programming features to patients and physicians, regardless of whether they are using the original InterStim INS or the new InterStim II INS.

Another new feature of the new system is the N'Vision clinician programmer, which works with all Medtronic neuromodulation therapies. The new software allows the physician to design and track the utilization of up to four stimulation programs for patients equipped with the programmer. When coupled with the InterStim iCon programmer, the new InterStim software enables improved clinical management of patient therapy, the company said.

Overactive bladder affects 33 million people in the U.S alone. Worldwide, more than 25,000 people have been treated with InterStim therapy.

In other news from Medtronic, the company reported that it has completed patient enrollment in the ENDEAVOR IV clinical study, paving the way for final data evaluation of the Endeavor drug-eluting coronary stent (DES) system and hopefully, ultimate submission to the FDA for U.S. approval.

Medtronic also said it has completed enrollment in two other important clinical trials: the RESOLUTE study evaluating the company's next-generation DES product and the ENDEAVOR-Japan study evaluating the Endeavor stent at 12 clinical sites in Japan.

“Completion of patient enrollment in these three trials is a tremendous achievement for the Endeavor clinical program,“ said Scott Ward, president of Medtronic's vascular business. “Along with the data from our previous Endeavor trials, the results of the ENDEAVOR IV study will provide a very comprehensive picture of Endeavor's clinical performance.“

The ENDEAVOR IV study is part of an extensive clinical program that also includes the ENDEAVOR I, II and III trials. Together, these trials will provide safety and efficacy data on more than 2,000 patients who have had the Endeavor stent implanted over the past 42 months, and this data will be used to support Medtronic's premarket approval submission to the FDA. Medtronic also is conducting an 8,000-patient international registry known as “e-FIVE“ outside the U.S.

ENDEAVOR IV is evaluating 1,548 patients at 80 clinical centers in the U.S., with a primary endpoint of target vessel failure (TVF) at nine months and a secondary endpoint of major adverse cardiac events (MACE) at 30 days.

The RESOLUTE study enrolled 130 patients at 12 clinical sites in Australia and New Zealand. Medtronic's next-generation drug-eluting stent uses the same stent platform and drug as the Endeavor stent (the Driver bare-metal cobalt alloy stent and Zotarolimus, or ABT-578), but incorporates a biocompatible drug delivery polymer developed by Medtronic instead of the PC Polymer licensed from Abbott Laboratories (Abbott Park, Illinois). This will allow Medtronic to leverage the strengths of Endeavor with the new polymer to extend the duration of drug in the vessel wall, addressing the delayed healing response in patients who have challenging clinical conditions.

The Endeavor-Japan clinical trial is a single-arm, prospective multicenter study with 99 patients and a primary endpoint of TVF at nine months. Data from this trial will be evaluated by the Duke Clinical Research Institute (Durham, North Carolina) and final results will be submitted to Japan's Ministry of Health, Labor and Welfare for ultimate approval in that country.

Endeavor received the CE mark in July 2005 and is available in about 100 countries. The company said it anticipates FDA approval in 2007.