(FOLD) Updates and Final Analysis Plan for Phase 3 Fabry Monotherapy Study 012

Last Patient Completes 18-Month Primary Treatment Period – Top-Line Data on Track to Report in 3Q14

96% of Patients with Amenable Mutations Elected to Continue in 12-Month Treatment Extension

Statistical Analysis Plan Finalized

CRANBURY, N.J., June 30, 2014  — Amicus Therapeutics (Nasdaq:FOLD), a biopharmaceutical company at the forefront of therapies for rare and orphan diseases, today provided updates and detailed the statistical analysis plan for its second Phase 3 study (Study 012) of the oral small molecule pharmacological chaperone migalastat HCl (“migalastat”) monotherapy for Fabry patients with amenable mutations. The 18-month primary treatment period is now complete and top-line data from Study 012 are expected in the third quarter of 2014. If successful, Study 012 will trigger the process for European regulatory approval of migalastat as a monotherapy for Fabry patients with amenable mutations.

Study 012 is the first clinical study to compare oral migalastat to standard-of-care enzyme replacement therapies (ERTs) for Fabry disease (Fabrazyme® and Replagal®). The primary outcome measure is renal function at 18 months. This open-label registration study enrolled 60 patients (26 males and 34 females) with Fabry disease with amenable mutations who had been treated with ERT for a minimum of 12 months prior to study entry. These patients were randomized 1.5:1 to switch to migalastat (36 patients) or remain on ERT (24 patients) for the primary 18-month treatment period, after which they were eligible to receive migalastat in a 12-month extension phase. Among the 60 patients enrolled, 56 (34 in the migalastat group and 22 in the ERT group) had amenable mutations in a GLP-validated human embryonic kidney (HEK) cell-based in vitro assay (“GLP HEK amenable”).

Study 012 (The ATTRACT Study, or AT1001-012) Patient Disposition Highlights

• Following randomization, 34 of 36 patients who switched to migalastat and 18 of 24 patients who continued with ERT completed the primary 18-month treatment period.
• Among patients completing the 18-month primary treatment period, 32 out of 34 in the migalastat group and 16 out of 18 in the ERT group had GLP HEK amenable mutations.
• 97% of patients with GLP HEK amenable mutations in the migalastat group (31 out of 32) elected to continue to receive migalastat in the 12-month treatment extension.
• 94% of patients with GLP HEK amenable mutations in the ERT group (15 out of 16) elected to switch from ERT to migalastat for the 12-month treatment extension.

John F. Crowley, Chairman and Chief Executive Officer of Amicus Therapeutics, Inc., stated, “We are very pleased to be advancing our Fabry monotherapy chaperone program into the final stages of drug development for Fabry patients with amenable mutations. Following on the heels of our recent positive results from our first Phase 3 registration Study 011, we are on track to report data in the third quarter of this year from Study 012, in which patients have volunteered to switch from ERT to our oral chaperone migalastat as their only therapy for Fabry disease. Pending positive data from this Study 012, we expect to submit a marketing application for migalastat monotherapy in Europe. We also plan to meet with the Food and Drug Administration in the fourth quarter of this year to discuss the data from both of our Phase 3 Fabry monotherapy studies, to determine the fastest U.S. registration pathway for migalastat. Together these studies represent the largest registration program ever conducted in Fabry disease. Hopefully, migalastat will become an important new medicine for the treatment of Fabry disease, where so much unmet need remains.”

Study 012 Statistical Analysis Plan:

Taking into account scientific advice from European regulatory authorities, the pre-specified co-primary outcome measures of efficacy in Study 012 are the descriptive assessments of comparability of the mean annualized change in measured (iohexol) glomerular filtration rate (mGFR) and estimated GFR (eGFR) for migalastat and ERT. Both mGFR and eGFR are considered important measures of renal function. Success on mGFR and eGFR will be measured in two ways:

• A 50% overlap in the confidence intervals between the migalastat and ERT treatment groups; and
• Whether the mean annualized changes for patients receiving migalastat are within 2.2 mL/min/1.73 m²/yr of patients receiving ERT.

Amicus has pre-specified that these renal function outcomes will be analyzed in patients with GLP HEK amenable mutations. Discussions with European regulators have centered on the entirety of the data to come from Study 012, considering the relatively low number of study participants due to the orphan nature of Fabry disease. In addition, in Europe the benefit/risk assessment is expected to be based on the overall data from this study and results from the entire clinical development program.

About Migalastat Monotherapy

Migalastat monotherapy is an oral small molecule pharmacological chaperone being investigated in two Phase 3 registration studies (Study 011 and Study 012) and an open-label extension study (Study 041) in Fabry patients with amenable mutations. Positive 12-month results from Study 011 were reported in the second quarter of 2014 and top-line data from Study 012 are anticipated in the third quarter of 2014.

About GLP HEK Amenable Mutations

Amenable mutations are defined as having an absolute increase of 3% of wild type alpha-Gal A enzyme activity and a relative increase of 20% when exposed to migalastat in a cell-based in vitro assay. All subjects enrolled in Study 012 had amenable mutations in the clinical trial human embryonic kidney (HEK) assay available at study initiation (“clinical trial assay”). Following the completion of enrollment, a GLP HEK assay was developed with a third party to measure the criteria for amenability with more quality control and rigor. However, approximately 10% of mutations in the HEK database switched categorization between “amenable” and “non-amenable” when moving from the clinical trial assay to the GLP HEK assay. Therefore, there were changes in categorization from amenable to non-amenable in 4 patients (2 per treatment arm) in Study 012. Based on results from mutations tested in the GLP HEK assay, Amicus continues to believe that approximately 30% to 50% of individuals with Fabry have mutations that are amenable to migalastat.

About Amicus Therapeutics

Amicus Therapeutics (Nasdaq:FOLD) is a biopharmaceutical company at the forefront of therapies for rare and orphan diseases. The Company is developing novel, first-in-class treatments for a broad range of human genetic diseases, with a focus on delivering new benefits to individuals with lysosomal storage diseases. Amicus’ lead programs include the small molecule pharmacological chaperones migalastat as a monotherapy and in combination with enzyme replacement therapy (ERT) for Fabry disease; and AT2220 (duvoglustat) in combination with ERT for Pompe disease.

Forward-Looking Statements

This press release contains, and the accompanying conference call will contain, “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 relating to preclinical and clinical development of Amicus’ candidate drug products, the timing and reporting of results from preclinical studies and clinical trials evaluating Amicus’ candidate drug products and the projected cash position for the Company. Words such as, but not limited to, “look forward to,” “believe,” “expect,” “anticipate,” “estimate,” “intend,” “potential,” “plan,” “targets,” “likely,” “may,” “will,” “would,” “should” and “could,” and similar expressions or words identify forward-looking statements. Such forward-looking statements are based upon current expectations that involve risks, changes in circumstances, assumptions and uncertainties. The inclusion of forward-looking statements should not be regarded as a representation by Amicus that any of its plans will be achieved. Any or all of the forward-looking statements in this press release may turn out to be wrong. They can be affected by inaccurate assumptions Amicus might make or by known or unknown risks and uncertainties. For example, with respect to statements regarding the goals, progress, timing and outcomes of discussions with regulatory authorities and the potential goals, progress, timing and results of preclinical studies and clinical trials, actual results may differ materially from those set forth in this release due to the risks and uncertainties inherent in the business of Amicus, including, without limitation: the potential that results of clinical or pre-clinical studies indicate that the product candidates are unsafe or ineffective; the potential that it may be difficult to enroll patients in our clinical trials; the potential that regulatory authorities may not grant or may delay approval for our product candidates; the potential that preclinical and clinical studies could be delayed because we identify serious side effects or other safety issues; the potential that we will need additional funding to complete all of our studies and, our dependence on third parties in the conduct of our clinical studies. Further, the results of earlier preclinical studies and/or clinical trials may not be predictive of future results. With respect to statements regarding projections of the Company’s cash position, actual results may differ based on market factors and the Company’s ability to execute its operational and budget plans. In addition, all forward looking statements are subject to other risks detailed in our Annual Report on Form 10-K for the year ended December 31, 2013. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, and Amicus undertakes no obligation to revise or update this news release to reflect events or circumstances after the date hereof. This caution is made under the safe harbor provisions of Section 21E of the Private Securities Litigation Reform Act of 1995.

FOLD–G

CONTACT: Investors/Media:
         Sara Pellegrino
         spellegrino@amicusrx.com
         (609) 662-5044

         Media:
         Dan Budwick
         dan@purecommunicationsinc.com
         (973) 271-6085