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VITAL SIGNS NAME: Raptor Pharmaceuticals HEADQUARTERS: Novato, CA STOCK PRICE AS OF 10/15/2014: $10.19 52 WEEK RANGE: $7.12-$17.72 MARKET CAPITALIZATION: $639 million EMPLOYEES: ~125 APPROVED COMPOUNDS: Cysteamine bitartrate delayed-release capsules (PROCYSBI®), FDA- approved in 2013 for treatment of nephropathic cystinosis in adults and children age 6 and older Meet the Company Copyright © Huntington Study Group 2014. All rights reserved. Secondary endpoints include all components of the UHDRS scale, as well as imaging, quantitative motor assessments, and some additional neuropsychiatric testing. HD INSIGHTS: Can you tell us briefly about the results? SMITH: In the data that have been released, total motor score deterioration was approximately 34 percent slower in the RP103- treated patients compared to placebo at 18 months in the 89 patients who completed that phase of the trial. This was not statistically significant. When we received those results we naturally wanted to understand more about individual measures and results in the trial to decide if it was worthwhile to continue. We looked at the other medications that study patients were taking, because some medications, particularly the neuroleptics like tetrabenazine are known to have an effect on patient voluntary movement ability. Total motor score is a collection of 15 different individual tests that measure involuntary and voluntary movements, and involuntary chorea is one component of the total motor score, which comprises approximately ten percent of the overall score. Approximately 33 percent of the study patients were found to be taking tetrabenazine to control their chorea. We looked at the treatment groups of the patients not taking tetrabenazine and other neuroleptics and antipsychotics just to see if those other treatments could have had the effect that we saw – a positive trend – or whether it was directly attributable to RP103. In the 66 patients who did not take tetrabenazine and who were treated with RP103 or placebo, we saw a 57 percent slower progression of total motor score deterioration compared to placebo. This was statistically significant (p=0.03) and clinically significant, and encouraged us to look at the individual measurements and different components of total motor score. The French investigators are working very hard to get all the data assembled and published. In terms of safety, I should also note that there were no unexpected adverse events with RP103. HD INSIGHTS: What are your plans for cysteamine? SMITH: We are very positive about cysteamine's potential in HD. The trial is ongoing, and we look forward to the 36 month results. As the second 18 months is open label with all patients taking RP103, we will not necessarily be able to compare the two arms of placebo treatment and continuous treatment with RP103 in terms of the total motor score, but there are other measurements such as imaging that may provide more insight into cysteamine's effectiveness over the full course of 36 months. A 36-month trial is pretty challenging to pull off, but patient retention has been strong. All patients who have finished have insisted on staying on open-label extension treatment. We have been able to grant patients access to RP103 for that purpose and we'll continue to do so until all patients complete their last treatment. We are in the process of speaking with regulators in the USA and Europe in an effort to clarify the path to approval of RP103 for use in HD. HD INSIGHTS: Thank you very much for your time and for your interest in HD therapeutics. SMITH: Thank you. It's our pleasure and our purpose. Meet Julie Smith, cont... 1 Paul BD, Sbodio JI, Xu R, Vandiver MS, Cha JY, Snowman AM, Snyder SH. Cystathionine γ-lyase deficiency mediates neurodegeneration in Huntington's disease. Nature. 2014 May 1;509(7498):96-100. doi: 10.1038/ nature13136. Epub 2014 Mar 26. H D I N S I G H T S HD Insights, Vol. 9 13