Devices Interventional Cardiology

 News Release - May 22, 2007

XTENT Announces Promising Six-Month Custom II Trial Data Presented at EuroPCR Meeting

Trial Included One of the Most Challenging Patient Populations Studied of Any Drug-Eluting Stent (DES) Clinical Trial

Webcast Slide Presentation to Review Data Tuesday, May 22 at 2:00p.m. EDT

BARCELONA and MENLO PARK, Calif., May 22 (HSMN NewsFeed) -- XTENT, Inc. (Nasdaq: XTNT ) announces positive six-month follow-up data from the CUSTOM II clinical trial, which assessed the safety and efficacy of the company's investigational Custom NX® drug-eluting stent (DES) system for the treatment of long and multiple lesions in patients with coronary artery disease.

The single-arm prospective study evaluated the use of CUSTOM NX in patients with long lesions, defined as greater than 20mm, and patients with two lesions. Of the 100 patients enrolled, 69 patients were enrolled in the long lesion arm, and 31 patients were enrolled in the two lesion arm of the study. Up to two customizable stent deployments of up to 60mm total length were evaluated in the study. The primary endpoint was Major Adverse Cardiac Events (MACE) at six months, with clinical follow-up at one, six and 12 months, then annually for five years. Angiographic and intravascular ultrasound (IVUS) follow-up was conducted at six months. The anticoagulation regimen was clopidogrel for a minimum of three months plus aspirin.

At six-month follow-up, the MACE rate was 9%. Early adverse events (in hospital) occurred in five patients, including four myocardial infarctions and one death. At six months, four additional patients (4%) underwent target lesion revascularization. Angiographic and IVUS results demonstrated in-stent late loss was 0.31mm; in-segment late loss was 0.22mm; binary restenosis rate was 7.5%; and the percentage of neointimal volume was 3.3%.

"These data are particularly encouraging considering CUSTOM II enrolled one of the most difficult-to-treat patient populations ever studied in a DES trial and also mirrored the complex disease profile physicians are most likely to see among patients presenting today with coronary artery disease," said Professor Eberhard Grube, MD, chief of cardiology at the Helios Heart Center in Siegburg, Germany and principal investigator of the CUSTOM II trial, who presented the data at the annual EuroPCR meeting in Barcelona. "Despite the complexity of patients treated, the Custom NX system allowed for very favorable results."

Difficult-to-Treat Patient Population

In the CUSTOM II patient population, the average vessel diameter was 2.57mm and the average lesion length was 28.7mm. Of the 100 patients enrolled in the trial, 26% were diabetic. The percentage of patients with ACC/AHA lesion grade B2 or C was 65.1%. This trial includes a high percentage of patients with complex lesions and one of the longest average lesion lengths studied of any DES clinical trial.

"The six-month clinical results from CUSTOM II are very promising and further our efforts to offer treatment options that meet the needs of patients with coronary artery disease," said Gregory D. Casciaro, President and CEO of XTENT. "In addition to the safety and efficacy data demonstrated, CUSTOM II achieved two firsts in coronary stenting history -- the first time a single stent system has been used to treat multiple lesions in multiple coronary arteries and the successful delivery of the longest coronary stent of any kind."

About the CUSTOM Trials

CUSTOM I was a 30 patient first-in-man study designed to evaluate the preliminary safety and feasibility of in-situ customization. CUSTOM I demonstrated positive early clinical results, with two MACE events in XTENT CUSTOM NX treated patients, zero restenosis and zero thrombosis at 12 month follow-up. The CUSTOM III clinical trial is also designed to evaluate in-situ customization for long lesions and multiple lesions. Enrollment of 90 patients at up to 15 European centers is ongoing. XTENT expects to submit an IDE application to the FDA within a timeframe to allow initiation of our pivotal studies in the second half of 2007.

CUSTOM II webcast and slide presentation

XTENT will host a webcast, slide presentation and telebriefing to review the CUSTOM II data Tuesday, May 22 at 2:00p.m. EDT (at 8:00p.m. CEST). The teleconference and slide presentation can be accessed via the investor relations section of the Company's website at http://investor.xtentinc.com/events.cfm or by calling 800-361-0912 (from the U.S.), 913-981-5559 (international). Please dial in or access the website 5 to 10 minutes prior to the beginning of the call. The webcast will be archived on the website for a minimum of three months, and can be accessed at the investor relations portion of the company's website at http://investor.xtentinc.com

About XTENT

XTENT, Inc. is a medical device company focused on developing and commercializing innovative customizable drug eluting stent (DES) systems for the treatment of coronary artery disease (CAD). CAD is the most common form of cardiovascular disease and the number one cause of death in the United States and Europe. XTENT® Custom NX® DES Systems are designed to enable the treatment of single lesions, long lesions and multiple lesions of varying lengths and diameters, in one or more arteries with a single device. Note: XTENT® Custom NX® DES Systems have not been approved for sale by any regulatory authority.

Forward Looking Statements

This press release contains forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Statements in this press release regarding XTENT's business that are not historical facts may be "forward-looking statements" that involve risks and uncertainties. Specifically, these statements include, but are not limited to those concerning: XTENT's ability to initiate its U.S. pivotal trial in the second half of 2007 and the ability of XTENT to enroll the anticipated number of patients in its CUSTOM III trial. Forward-looking statements are based on management's current, preliminary expectations, and are subject to risks and uncertainties that could cause actual results to differ from the results predicted and which are included in the "Risk Factors" section of our most recent quarterly report on Form 10-Q for the quarter ended March 31, 2007. This quarterly report was filed with the SEC on May 14, 2007, and is available on our investor relations website at www.xtentinc.com and on the SEC's website at http://www.sec.gov. Undue reliance should not be placed on forward-looking statements, which speak only as of the date they are made. XTENT undertakes no obligation to update publicly any forward-looking statements to reflect new information, events or circumstances after the date they were made, or to reflect the occurrence of unanticipated events.

Information about XTENT is available at our website at http://www.xtentinc.com.

Source: XTENT

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