This study is testing a drug called TenoMiR that is being developed for the treatment of tennis elbow (lateral epicondylitis). The study drug is a new compound that works by improving the quality of the collagen which helps repair damage to the elbow. The study drug is being developed in the hope of providing a more reliable treatment than those currently available and can be given at the time of first diagnosis, so that recovery can begin as soon as possible.

TenoMiR a chemically synthesised mimic of microRNA-29a (miR29a) which has improved stability, activity and cellular uptake while being non-immunogenic, has been created to restore miR29a levels back to pre-injury levels.

TenoMiR is unique in directly targeting the key changes in collagen production associated with tendinopathy. Unlike other therapies, TenoMiR has a well-defined mode-of-action that is supported by a wealth of scientific data. Moreover, treatment with TenoMiR does not require invasive biopsies and can be delivered at the point of initial diagnosis initiating recovery at the very earliest time.

Inclusion Criteria:

1. Subject has a clinical diagnosis of lateral epicondylitis.

2. Aside from lateral epicondylitis, the subject is otherwise healthy as determined by a responsible physician, based on medical history, physical examinations, concomitant medication, vital signs, 12-lead ECGs and clinical laboratory evaluations. Laboratory values may be re-tested once at the discretion of the Investigator.

3. Subject's symptoms can be reproduced with resisted supination or wrist dorsiflexion (as confirmed by tenderness at lateral epicondyle and positive pick up back of chair sign).

4. Subject's symptoms have persisted for at least 6 weeks to 6 months, despite conservative treatment that includes 1 or combinations of:

   1. Physical therapy
   2. Splinting
   3. NSAIDs

Exclusion Criteria:

Subjects with any of the following will be excluded from study participation:

1. Subject has undergone previous corticosteroid injection therapy to the affected elbow in less than 6 months prior to enrolment.
2. Subjects unwilling or unable to discontinue use of pain medication (opiate or NSAID) from at least 1 week prior to Investigational Medicinal Product (IMP) administration.
3. Subject has received previous Platelet-Rich Plasma (PRP) injection to the affected elbow.
4. Subject uses or has recent use of medications known to affect the skeleton (e.g., glucocorticoid usage >5 mg/day, fluoroquinolone antibiotics).
5. Subject has undergone surgical intervention to the affected elbow for the treatment of lateral epicondylitis.