GI Dynamics Announces New Data Demonstrating Feasibility of EndoBarrier® Re-Implantation

Lexington, Mass., and Sydney, Australia – April 27, 2012 – GI Dynamics, Inc. (ASX: GID) today announced new data results that demonstrate the feasibility and safety of re-implantation of EndoBarrier®, a breakthrough device for the treatment of type 2 diabetes and/or obesity. These data were presented for the first time by Alex Escalona, M.D., Department of Digestive Surgery, Pontificia Universidad Católica de Chile, Santiago, Chile, during an oral session on Thursday, April 26, 2012, at the 5th Congress of the International Federation for the Surgery of Obesity and Metabolic Disorders, European Chapter (IFSO-EC) in Barcelona.

In addition, information about EndoBarrier Therapy, including how it works, key benefits and clinical results to date, will be presented by Jan Willem Greve, M.D., Ph.D., Gastrointestinal and Bariatric Surgery, Atrium Medical Center Parkstad, Heerlen, the Netherlands, during a roundtable discussion at the Metabolic Surgery Symposium at IFSO-EC on Friday, April 27, 2012.

“The efficacy of first-time EndoBarrier Therapy in weight loss and blood sugar control have been well established, and these results demonstrate that EndoBarrier can be safely re-implanted in patients who have previously undergone treatment with the device,” said Dr. Escalona. “Re-implantation of the EndoBarrier may facilitate additional weight loss and improvements in diabetes and other co-morbid conditions, and additional studies evaluating these clinical benefits are ongoing. We believe this is very exciting news for patients who may benefit from another period of EndoBarrier Therapy.” Twenty-four obese patients with an average weight of 109 kg (239.8 lbs.) and an average body mass index (BMI) of 44 completed 12 months of EndoBarrier Therapy, achieving a mean weight loss of 20 percent (22 kg/44.4 lbs) and excess weight loss of 47 percent. Following their initial treatment period and at least 31 weeks of follow-up post EndoBarrier removal, these patients were invited to participate in a re-implant study. In this study, 19 of the eligible 24 obese patients were re-implanted with the EndoBarrier. The mean time from EndoBarrier removal to re-implant was 39.4 weeks (range: 31-52 weeks). All of the patients who participated in the study were successfully re-implanted with EndoBarrier and there were no procedure-related complications.

“We are pleased to have these data presented showcasing the ability to successfully re-implant the EndoBarrier, and we look forward to sharing data on the efficacy of second time EndoBarrier Therapy later this year,” said Stuart A. Randle, president and CEO, GI Dynamics, Inc.

About EndoBarrier® Therapy

EndoBarrier is a breakthrough device for the treatment of type 2 diabetes and/or obesity that has been clinically demonstrated to lower HbA1c levels, achieve weight loss of more than 20 percent, and improve important metabolic measures including cholesterol, blood sugar and triglycerides.1 It has been studied in 13 clinical trials and has been used in more than 500 patients. EndoBarrier is a thin, flexible, tube-shaped liner that forms a physical barrier between food and a portion of the wall of the intestine. Once implanted, EndoBarrier Therapy affects certain gastrointestinal hormones involved in insulin sensitivity, glucose metabolism and satiety, and these changes allow for rapid and sustained improvement of type 2 diabetes and weight loss.2

EndoBarrier received CE Mark approval for Europe in 2010 as well as approval by the Therapeutic Goods Administration in Australia in 2011 for the treatment of type 2 diabetes and/or obesity. EndoBarrier is currently commercially available in select European markets, Chile and Australia. For more information, please visit www.endobarrier.com.

1Moura, GHD, et al, One Year Results of an Endoscopic, Duodenal-Jejunal Exclusion Device for Weight Loss and Control of Type 2 Diabetes. Hospital das Clinicas, University of São Paulo, São Paulo, Brazil. DT&T, February 2012, vol 14, no.2:183-189.

2 C de Jonge, JW Greve, N Bouvy, et al, EndoBarrier Gastrointestinal Liner treatment rapidly improves diabetes parameters paralleled by increased postprandial GLP-1 and PYY levels in obese type 2 diabetic patients, Department of Surgery, Maastricht University Medical Centre, presented at IFSO 2011, Hamburg, Germany.

About GI Dynamics

GI Dynamics, Inc. (ASX: GID) is pioneering the development and commercialization of effective, non-surgical treatments targeting the large and growing global patient populations with type 2 diabetes and obesity. The company’s flagship product, the EndoBarrier®, is a novel, non-surgical device proven to lower blood glucose levels and promote weight loss in diabetic patients and/or obese patients during the implant period. GI Dynamics currently markets the EndoBarrier in select regions in Europe, South America and Australia and is planning near-term commercial expansion into additional European countries. EndoBarrier is not approved for sale in the United States and is considered investigational. Founded in 2003, GI Dynamics is headquartered in Lexington, Massachusetts. For more information, please visit www.gidynamics.com.

Forward-Looking Statements

This announcement contains or may contain forward-looking statements that are based on management’s beliefs, assumptions and expectations and on information currently available to management. All statements that address operating performance, events or developments that we expect or anticipate will occur in the future are forward-looking statements, including without limitation our expectations with respect to our ability to commercialize our EndoBarrier® including our estimates of potential revenues, costs, profitability and financial performance; our ability to develop and commercialize new products including our ability to obtain reimbursement for our products; our expectations with respect to our clinical trials, including enrollment in or completion of our clinical trials and our associated regulatory submissions and approvals; our expectations with respect to the integrity or capabilities of our intellectual property position. Management believes that these forward-looking statements are reasonable as and when made. You should not place undue reliance on forward-looking statements because they speak only as of the date when made. GI Dynamics does not assume any obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. GI Dynamics may not actually achieve the plans, projections or expectations disclosed in forward-looking statements, and actual results, developments or events could differ materially from those disclosed in the forward-looking statements. Forward-looking statements are subject to a number of risks and uncertainties, described in “Risk Factors” in our Prospectus lodged with the Australian Securities & Investments Commission on 3 August 2011.

Investor Enquiries:

United States

Robert Crane, Chief Financial Officer

+1 (781) 357-3250

Australia

David Allen / Alan Taylor, Inteq Limited

+61 2 9231 3322

Media Enquiries:

North America/Europe:

Dan Budwick, Pure Communications Inc.

+ 1 (973) 271-6085

Australia:

Rebecca Wilson, Buchan Consulting Group

+61 3 9866 4722

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