1. Duchenne Muscular Dystrophy Program Developing utrophin modulator therapies for the potential treatment of all DMD patients

2. Legal Disclaimer Statements in this presentation, other than statements of historical facts, constitute forward-looking statements within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include statements regarding Summit’s clinical trials supporting the safety and efficacy of its product candidates and the potential novelty of such product candidates as treatments for disease, plans and objectives for clinical trials and product development, strategies, future performance, expectations, assumptions, financial condition, liquidity and capital resources. These forward-looking statements may be preceded by, followed by or otherwise include the words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue,” and similar expressions. Actual results or events may differ materially from those expressed or implied in any forward-looking statements due to various factors, including the risks and uncertainties inherent in clinical trials and product development and commercialization, such as the uncertainty in results of clinical trials for product candidates, the uncertainty of whether the results of clinical trials will be predictive of results in later stages of product development, the risk of delays or failure to obtain or maintain regulatory approval, the risk of failure of the third parties upon whom Summit relies to conduct its clinical trials and manufacture its product candidates to perform as expected, the risk of increased cost and delays due to delays in the commencement, enrollment, completion or analysis of clinical trials or significant issues regarding the adequacy of clinical trial designs or the execution of clinical trials and the timing, cost and design of future clinical trials and research activities, the timing of expected filings with the FDA or other regulatory agencies; and the other risks and uncertainties described in Summit’s public filings with the Securities and Exchange Commission. Summit may not actually achieve the plans, intentions or expectations disclosed in its forward-looking statements, and you should not place undue reliance on its forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in forward-looking statements. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. Summit disclaims any intent or obligation to revise or update these forward-looking statements, except as required by applicable law. November 20152Action Duchenne "A Brave New World"

3. Thank you to the patients and their families, and the organisations who have supported our program Action Duchenne "A Brave New World"3November 2015

4. Utrophin and Dystrophin Two proteins, one major function – stabilise muscle fibre membranes Description of hypothesis Confirmation of approach in vivo Utrophin modulator pipeline November 20154Action Duchenne "A Brave New World"

5. Comparison Between Dystrophin and Utrophin Function November 20155 DystrophinUtrophin Muscle specific transcripts  Early foetal muscle expression  Mature muscle expression  Mature fibre localisationComplete lengthNMJ, MTJ Fibre repair  Specific fibre binding sitesCostamere Protein binding partners Dystrophin Protein Complex  nNOS  Microtubules  Actin  Action Duchenne "A Brave New World"

6. Dystrophin or Utrophin Protein: Maintaining the Function of Muscle Fibers Contractile apparatus Dystrophin or Utrophin Costamere Section through a muscle fibre Finite number of springs Finite number of binding sites Contraction and relaxation stress transmitted through costamere anchor sites Muscle fibre membrane November 2015Action Duchenne "A Brave New World"6 No springs Structural failure No dystrophin (Duchenne) Structural failure Fewer springs Still functional but lower weight capacity Less dystrophin (Becker) Still functional but lower stress tolerance

7. Utrophin is Functionally Equivalent to Dystrophin in Developing and Repairing Muscle >Modulation of utrophin protein has potential to compensate for lack of dystrophin November 20157Action Duchenne "A Brave New World"

8. Summit’s Utrophin Modulation Approach Utrophin gene expression is switched off in myonuclei once repair to a damaged region of the fibre has been made Exactly same mechanism operating in DMD muscle Development of an oral drug treatment where the drug enters muscle fibre myonuclei, via blood circulation, to switch on and maintain utrophin gene expression continuously Mouse dosed orally with SMT C1100 Each “dot” radiolabelled SMT C1100 * Example positive C1100 myonuclei Action Duchenne "A Brave New World"8November 2015 * *

9. Utrophin Modulators Increase Utrophin Expression Along Muscle Fibres in mdx Models >Utrophin localised along the entire length of the membrane with drug treatment >Reconstruction of the dystrophin protein complex >Stabilises membrane reducing rate of degeneration mdx control mdx + SMT C1100mdx + 2 nd Generation β-dystroglycan (EDL) Utrophin (TA) November 2015 Source: Human Mol Genet, (2015), 24 (15) 4212-4224 9Action Duchenne "A Brave New World"

10. Increased Resistance to Muscle damage November 2015 Source: Human Mol Genet (2015), 24 (15), 4212-4224: PLoS ONE (2011), 6 (5), e19189 10 Utrophin Modulation Protected Against Loss of Muscle Function in mdx Disease Model Action Duchenne "A Brave New World"

11. Utrophin Modulator Pipeline November 2015Action Duchenne "A Brave New World"11

12. Our Utrophin Development Pipeline Action Duchenne "A Brave New World"12 Discovery Clinical Trial Preparation Phase 1Phase 2 SMT C1100 Second Generation Future Generations PRODUCT >Disease modifying approach >Potential to treat all DMD patients regardless of the dystrophin mutation November 2015

13. SMT C1100 Overview Molecule: First-generation, small molecule utrophin modulator Status: >Met primary objective in Phase 1b modified diet clinical trial >Received Orphan Drug Designation from the FDA and Orphan Medicinal Product Designation from the EMA Clinical Data-to-Date: >Well-tolerated in ~100 healthy volunteers and 24 DMD patients >Phase 1b modified diet clinical trial demonstrated improved drug exposure in patients following specific dietary guidance November 2015 >>> Next Milestone: Phase 2 proof of concept trial expected to start Q4 2015 13Action Duchenne "A Brave New World"

14. Phase 1b Modified Diet Trial Design Evaluated plasma levels of SMT C1100 in DMD patients following specific dietary guidance providing for a balanced diet of fats, proteins and carbohydrates Study Design:>12 ambulatory DMD patients aged 5-13 years old >Placebo controlled, dose escalating trial >14 days of oral dosing Primary Objective:>PK of SMT C1100 Secondary Objectives:>Safety/tolerability of SMT C1100 >Evaluate variability in steady state PK >Evaluate CK levels as a potential biomarker of SMT C1100 activity November 201514Action Duchenne "A Brave New World"

15. Modified Diet Phase 1b Results: Increased Exposure in Patients who had Participated in First Phase 1b Trial >All seven patients who participated in previous Phase 1b trial had increased exposures when following dietary guidance >Seven of the 12 patients had higher exposure after Day 14 compared to Day 1, which was not observed in previous trials of SMT C1100 November 2015 >>>Potential for all DMD patients to benefit from continued utrophin production >>>Data support advancement to Phase 2 proof of concept trial * (Fixed Dose) 15Action Duchenne "A Brave New World" * Excludes 1 patient who had AUC >1215 in both studies

16. Next Steps: Phase 2 Proof of Concept Trial >Trial to evaluate clinical benefit of SMT C1100 in patients with DMD >Expected initiation Q4 2015 >Plan to report interim data periodically Planned Study Design:Open label trial expected to enrol up to 40 ambulatory DMD patients aged 5-10 years old 48 week trial Sites in Europe and US PK not part of inclusion criteria November 201516Action Duchenne "A Brave New World"

17. Phase 2 Proof of Concept Trial: Range of Mechanism and Efficacy Measures Planned MECHANISM Utrophin protein levels Muscle fibre regeneration MUSCLE HEALTH Magnetic Resonance Imaging (MRI) Serum biomarkers FUNCTION Six minute walk test North Star Ambulatory Assessment November 201517Action Duchenne "A Brave New World"