Effect of Givinostat, an HDAC inhibitor, on disease milestones in Duchenne Muscular Dystrophy boys Paolo Bettica1, M.D., Ph.D., Giacomo P. Comi2, M.D., Enrico Bertini3, M.D., Giuseppe Vita3, M.D., Eugenio Mercuri4, M.D, Sara Cazzaniga1§, M.Sc. 1 Italfarmaco S.p.A., Italy; 2 Dino Ferrari Centre Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milan, Italy; 3 Bambino Gesù Children's Hospital, IRCCS, Rome. Italy; 3 University of Messina, NEMO Clinical Centre, Messina, Italy; 4 Catholic University, Rome, Italy; Corresponding Author§ email: [email protected]

PHASE 3 TRIAL Phase 3, multicentre, double blind, placebo controlled (2:1) study in 242 patients to What happens at study visits? • demonstrate that Givinostat oral suspension preserves muscle mass and slows down disease Informed Consent Paperwork • progression. The study is ongoing in USA, Canada and European countries. A total of 15 visits (every 3 months): • Blood draw more frequently during the first 3 months: • first month: weekly • second month: every 2 weeks • from the third month: every 3 months What does participant entail?: • Surveys (baseline, at 12 and 18 months) and Diaries • must be ambulant DMD boys from 6 years (every visit) of age, • Muscle tests every 3 months (6MWT, NSAA, 4SC, QMT) • on stable corticosteroid for at least 6 • Pulmonary Function test baseline, at 12 and 18 months months prior to start the treatment, • Thigh muscle MRI: baseline, at 12 and 18 months • able to perform the 4 stairs climb in no • Upon successful completion of the study, participants, more than 8 seconds and time to stand up regardless the ability to walk, will have the opportunity to in ≥ 3 and less than 10 seconds, enter into long term safety study and they will ALL receive the • do the MRI scan drug

Givinostat Mechanism of Action in Duchenne

Downstream effects of the Impact on the lack of dystrophin epigenetic effects of the lack of dystrophin Mechanical effects : . Increased muscle damage HDAC inhibition1: . Muscle cell membrane instability Increased translation of . Muscle cell necrosis muscle regeneration factors with an increase Epigenetic effects: in muscle regeneration . Direct: Lack of DAPC leads to a Reduced activation of hyperactive HDAC repressing the immune cells with a translation of muscle reduction in pro- regeneration factors inflammatory . Indirect: Damage-associated release molecular pattern (DAMP)  release and increased Reduced fibroblast lead to activation of immune cells activation with a and fibroblast, which can be reduction in fibrosis halted by HDAC inhibition

STUDY 43: PULMONARY FUNCTION STUDY 43-51: METHODS Study 43 Design - The study was an open label 2-part, phase 2 clinical FVC% Predicted: 2.3% yearly decline PEF% Predicted: no decline trial, which enrolled 20 ambulant DMD boys aged 7 to <11 years. Boys were on a stable dose of corticosteroids for ≥ 6 months2. The study was A 4 to 6% yearly rate4, 5, 6 of extended to allow the continuation of the treatment until 52 month. decline in FVC% Predicted Participants were transferred to Study 51 and on November 2017, 16 (Forced Vital Capacity) and are still on treatment. PEF% Predicted (Peak Expiratory Flow, PEF) has Study 43 Study 43 Study 43 Study 51 2 Month 12 Month 36 Month Long Term Study 51 been shown in natural Follow Up Extension Study still ) ) Dose Finding d d history studies in a patient July 2013 - July 2014 – Nov 2017– ongoing e e May – July 2013 r

r July 2014 Nov 2017 Nov 2018 p

p population comparable to % % ( (

that of Study 43. F C E V P F SAFETY Givinostat treatment for 4.4 The most frequent Adverse Events were: years leads to a delay in the decline of the respiratory • count reduction parameters • dose-dependent, asymptomatic and fully reversible; may Age (years) appear within the first weeks of treatment at the non Age (years) tolerated doses 95% Prediction Limits 95% Confidence Limits Expected Patient data 95% Prediction Limits 95% Confidence Limits Expected Patient data • Nausea, vomiting, abdominal pain and diarrhea: generally mild to moderate and transient STUDY 43-51 (5.4 years of treatment): DISEASE MILESTONE • Transient and reversible increase of Triglyceride level in some subjects CONCLUSION

• Compared to the published natural history data, Givinostat administration appears to be associated with a slowdown of the disease progression • Givinostat was tolerated at the doses used • The ongoing Epidys Phase 3 is supported by the preliminary results of the ongoing long safety study REFERENCES

1 Consalvi et al. Preclinical studies in the mdx mouse model of duchenne muscular dystrophy with the inhibitor givinostat. Mol Med. 2013;19:79-87. 2 Bettica et al. Histological effects of givinostat in boys with Duchenne muscular dystrophy. Neuromuscul Disord. 2016;26:643-649. 3 McDonald et al. Long-term effects of glucocorticoids on function, quality of life, and survival in patients with Duchenne Age 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 muscular dystrophy: a prospective cohort study. Lancet. 2018;391(10119):451-461 Subjects at risk 19 19 19 19 19 19 19 19 19 19 19 18 17 16 9 3 3 0 0 0 0 0 0 0 0 0 4 Mayer et al. Characterization of pulmonary function in Duchenne Muscular Dystrophy. Paediatr Pulmonol 2015 5 Henricson, E. et al. The cooperative international neuromuscular research group Duchenne natural history study: glucocorticoid treatment preserves clinically meaningful functional milestones and reduces rate of disease progression as measured by manual muscle testing and other commonly used clinical trial outcome measures. Muscle & nerve 2013; 8 (1), 3 Contrasted with the natural history published results (CINRG study ) study 43-51 results suggest that the addition of Givinostat 55-67. 6 Kinane et al. Long-Term Pulmonary Function in Duchenne Muscular Dystrophy: Comparison of Eteplirsen-Treated Patients to steroid treatment delays disease progression to Natural History. J Neuromuscul Dis 2018, 5 (1), 47-58.