Lateral EpicondylitisPhase 1NCT04686799
Doxycycline for Elbow Tendinopathy
A Phase 1 study testing Doxycycline Hyclate 20 MG in people with Lateral Epicondylitis and Lateral Epicondylitis, Left Elbow, run by Hospital for Special Surgery, New York at 1 site in United States.
Trial summary
To evaluate the feasibility of subantimicrobial -dose (SD) doxycycline to improve outcomes of nonsurgical management of elbow tendinopathy via matrix metalloproteinase (MMP) inhibition as well as evaluate if participants will be compliant to with prescribed medication and exercise treatment. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Lateral Epicondylitis, Lateral Epicondylitis, Left Elbow, Lateral Epicondylitis, Right Elbow
- What is being tested?
- Doxycycline Hyclate 20 MG
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 21 participants
- Where
- 1 siteUnited States
- Study dates
- 3 Dec 2020to 9 Oct 2025
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Males and females ages of 18 and up
- Atraumatic unilateral elbow pain of ≥ 6 weeks duration
- Diagnosed clinically as lateral or medial elbow tendinopathy
- Activity-related lateral or medial elbow pain
- Tenderness of the lateral or medial epicondyle
- Pain with gripping and/or resisted wrist extension with the elbow extended
- Pain with passive wrist flexion and finger with the elbow extended
- Internet access to complete electronic surveys
Who cannot join
- Prior surgery of the affected elbow
- Prior injection of the affected lateral or medial epicondyle or extensor tendons
- Prior extracorporeal shockwave therapy to the affected elbow
- Suspicion for radial tunnel syndrome (tenderness distal to the lateral epicondyle in the area of the supinator muscle dorsally, pain with resisted supination with the elbow extended, and/or weakness of the extensor digitorum communis)
- Separate upper extremity injury or condition that would interfere with full participation in the home exercise program
- Fluoroquinolone-associated tendinopathy
Show all 15Show fewer
- Ligamentous laxity on exam
- Evidence of osteoarthritis or osteochondral lesion on radiographs
- Autoimmune condition
- Pregnant, intend to become pregnant, or breastfeeding
- Premenopausal women who are not using contraception
- Allergy to doxycycline or other tetracyclines
- Current esophagitis or peptic ulcer disease
- Current use of medication for which there is a drug interaction with doxycycline
- Who do not speak English
Trial locations and contacts
1 site in 1 country.
United States1 site
Hospital for Special Surgery
New York, New York, 10021
About this study
Official title: Evaluating the Feasibility of Subantimicrobial-dose Doxycycline for Elbow Tendinopathy
To evaluate the feasibility of subantimicrobial -dose (SD) doxycycline to improve outcomes of nonsurgical management of elbow tendinopathy via matrix metalloproteinase (MMP) inhibition as well as evaluate if participants will be compliant to with prescribed medication and exercise treatment. Our working hypothesis is that patients with elbow tendinopathy will be receptive to treatment with SD-doxycycline and compliant with the prescribed treatment.
Read the detailed description
: elbow tendinopathy is a common condition among athletes and the general population. It can result in significant disability and time loss from work. Despite traditional nonsurgical treatment, symptoms often persist for more than 6 months. Second-line treatments, such as platelet rich plasma injections and extracorporeal shock wave therapy, have limited evidence and are often cost-prohibitive. There remains a need for additional cost-effective nonsurgical treatment for elbow tendinopathy.
Purpose: To evaluate the feasibility of subantimicrobial -dose (SD) doxycycline to improve outcomes of nonsurgical management of elbow tendinopathy via matrix metalloproteinase (MMP) inhibition as well as evaluate if participants will be compliant to with prescribed medication and exercise treatment. Our working hypothesis is that patients with elbow tendinopathy will be receptive to treatment with SD-doxycycline and compliant with the prescribed treatment.
Methods: This study will enroll 25 otherwise healthy males and females ages 18 and up with ≥ 6 weeks of symptomatic lateral or medial elbow tendinopathy. Subjects will receive doxycycline 20 mg BID (twice a day) for 12 weeks. Usual care will also be provided with a home exercise program and a counterforce brace. The proportion of eligible patients who elect to participate in the study will be tracked as a measure of receptiveness. Biweekly logs will be collected to monitor for treatment side effects and track compliance. Patient reported outcomes will include quick Disabilities of the Arm Shoulder and Hand score (qDASH) and Patient-Rated Tennis Elbow Evaluation (PRTEE) at baseline, 4, 8, and 12 weeks. Ultrasound tendinopathy grade and grip strength will be measured at baseline and 12 weeks. Blood will be drawn to assess MMP activity and collagen production/connective tissue anabolism at baseline and 12 weeks.
Significance: This study will provide the necessary data to design a phase two-a trial of a safe, low-cost adjuvant treatment for a common condition treated by sports medicine and primary care physicians. If found to be beneficial for elbow tendinopathy, SD-doxycycline may have utility in other types of tendinopathy as well.
- Conditions
- Lateral Epicondylitis, Lateral Epicondylitis, Left Elbow, Lateral Epicondylitis, Right Elbow, Lateral Epicondylitis, Unspecified Elbow, Lateral Epicondylitis (Tennis Elbow) Bilateral, Medial Epicondylitis
- Being tested
- Doxycycline Hyclate 20 MG
- Keywords
- Feasibility, efficacy
- Medical subject headings
- Tennis Elbow, Elbow Tendinopathy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Doxycycline Hyclate 20 MGDrug
Subjects will receive doxycycline 20 mg BID
| Study group | Role | What they receive |
|---|---|---|
| SD-doxycycline group | Experimental | 12 weeks SD-doxycycline: doxycycline hyclate 20 mg tablet by mouth twice daily Receives: Drug: Doxycycline Hyclate 20 MG |
What is being measured
The primary outcome is the main question the study is designed to answer.
Primarily a feasibility study of SD-doxycycline as an adjunctive treatment for elbow tendinopathy (Compliance)
Compliance: At the end of the study, compliance will be calculated using the number of self-reported doses taken divided by the number of prescribed doses (twice daily x 7 days per week x 12 weeks = 168 doses).
Measured: 12 weeks
Receptiveness
The number of patients who enroll in study divided by the number eligible patients minus the number of patients who decline due to reasons unrelated to the prescribed treatment, e.g., unable to return for second study visit. This will be measured at time of study recruitment.
Measured: 12 weeks
Secondary outcomes (5)
Clinical outcomes - qDASH
quick Disabilities of the Arm Shoulder and Hand score (by qDASH score) at baseline, 4, 8, and 12 weeks
Measured: 12 weeks
Clinical outcomes - PRTEE
Patient-Rated Tennis Elbow Evaluation (by PRTEE test ) at baseline, 4, 8, and 12 weeks
Measured: 12 weeks
Secondarily, clinical outcomes will be measured to provide preliminary data to power a future randomized controlled trial. (Ultrasound tendinopathy grade)
Ultrasound tendinopathy grade at baseline at 12 weeks - by ultrasound
Measured: 12 weeks
Clinical outcomes - Grip strength
Grip strength at baseline and 12 weeks - measure by hand-held dynamometer
Measured: 12 weeks
Clinical outcomes - MMP
Matrix metalloproteinase (MMP) inhibition activity and collagen production/connective tissue anabolism at baseline and 12 weeks - measure by blood test
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Dec 2020
- Study start3 Dec 2020
- Primary completion9 Oct 2025
- Study completion9 Oct 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Lateral EpicondylitisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- The plan for achieving the specific aims is to first assess patient receptiveness by screening patients with symptomatic lateral or medial elbow tendinopathy for eligibility and tracking the proportion of eligible patients who decline participation in the study due to not wanting to take an extended course of SD-doxycycline. 25 subjects will given SD-doxycycline and have the tendinopathy grade measured by ultrasound. The medication will be prescribed for 12 weeks during which time logs will be used to track compliance and monitor side effects. This will be done in combination with usual care, which includes a home exercise program, a counterforce brace, and over-the-counter pain medication to use as needed. Clinical effectiveness outcomes will include patient reported outcomes, ultrasound tendinopathy grade, grip strength, and markers of MMP activity and collagen production/connective tissue anabolism.
- Masking
- None (open label)
- Enrolment
- 21 participants (actual)
Sponsor and investigators
- Lead sponsor
- Hospital for Special Surgery, New York
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Brett G Toresdahl, MD, Principal investigator, Hospital for Special Surgery, New York
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04686799
- Sponsor's protocol ID
- 2020-1582
- Status last verified
- Jan 2025
- First submitted
- 6 Nov 2020
- Last updated
- 28 Apr 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: All individual participant data collected during the trial after deidentification
Study at a glance
From the registry record, last updated by the sponsor on 28 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating the Feasibility of Subantimicrobial-dose Doxycycline for Elbow Tendinopathy
- ClinicalTrials.gov ID
- NCT04686799
- Acronym / sponsor ID
- 2020-1582
- Conditions
- Lateral Epicondylitis, Lateral Epicondylitis, Left Elbow, Lateral Epicondylitis, Right Elbow, Lateral Epicondylitis, Unspecified Elbow, Lateral Epicondylitis (Tennis Elbow) Bilateral, Medial Epicondylitis
- Keywords
- Feasibility, efficacy
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 21 participants (actual)
- Lead sponsor
- Hospital for Special Surgery, New YorkUniversity, hospital or other
- Study start
- 3 Dec 2020 (actual)
- Primary completion
- 9 Oct 2025 (actual)
- Study completion
- 9 Oct 2025 (actual)
- First posted
- 29 Dec 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To evaluate the feasibility of subantimicrobial -dose (SD) doxycycline to improve outcomes of nonsurgical management of elbow tendinopathy via matrix metalloproteinase (MMP) inhibition as well as evaluate if participants will be compliant to with prescribed medication and exercise treatment. Our working hypothesis is that patients with elbow tendinopathy will be receptive to treatment with SD-doxycycline and compliant with the prescribed treatment.
Detailed description
: elbow tendinopathy is a common condition among athletes and the general population. It can result in significant disability and time loss from work. Despite traditional nonsurgical treatment, symptoms often persist for more than 6 months. Second-line treatments, such as platelet rich plasma injections and extracorporeal shock wave therapy, have limited evidence and are often cost-prohibitive. There remains a need for additional cost-effective nonsurgical treatment for elbow tendinopathy.
Purpose: To evaluate the feasibility of subantimicrobial -dose (SD) doxycycline to improve outcomes of nonsurgical management of elbow tendinopathy via matrix metalloproteinase (MMP) inhibition as well as evaluate if participants will be compliant to with prescribed medication and exercise treatment. Our working hypothesis is that patients with elbow tendinopathy will be receptive to treatment with SD-doxycycline and compliant with the prescribed treatment.
Methods: This study will enroll 25 otherwise healthy males and females ages 18 and up with ≥ 6 weeks of symptomatic lateral or medial elbow tendinopathy. Subjects will receive doxycycline 20 mg BID (twice a day) for 12 weeks. Usual care will also be provided with a home exercise program and a counterforce brace. The proportion of eligible patients who elect to participate in the study will be tracked as a measure of receptiveness. Biweekly logs will be collected to monitor for treatment side effects and track compliance. Patient reported outcomes will include quick Disabilities of the Arm Shoulder and Hand score (qDASH) and Patient-Rated Tennis Elbow Evaluation (PRTEE) at baseline, 4, 8, and 12 weeks. Ultrasound tendinopathy grade and grip strength will be measured at baseline and 12 weeks. Blood will be drawn to assess MMP activity and collagen production/connective tissue anabolism at baseline and 12 weeks.
Significance: This study will provide the necessary data to design a phase two-a trial of a safe, low-cost adjuvant treatment for a common condition treated by sports medicine and primary care physicians. If found to be beneficial for elbow tendinopathy, SD-doxycycline may have utility in other types of tendinopathy as well.
Study design
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- The plan for achieving the specific aims is to first assess patient receptiveness by screening patients with symptomatic lateral or medial elbow tendinopathy for eligibility and tracking the proportion of eligible patients who decline participation in the study due to not wanting to take an extended course of SD-doxycycline. 25 subjects will given SD-doxycycline and have the tendinopathy grade measured by ultrasound. The medication will be prescribed for 12 weeks during which time logs will be used to track compliance and monitor side effects. This will be done in combination with usual care, which includes a home exercise program, a counterforce brace, and over-the-counter pain medication to use as needed. Clinical effectiveness outcomes will include patient reported outcomes, ultrasound tendinopathy grade, grip strength, and markers of MMP activity and collagen production/connective tissue anabolism.
| Arm | Type | Receives |
|---|---|---|
| SD-doxycycline group | Experimental | Drug: Doxycycline Hyclate 20 MG12 weeks SD-doxycycline: doxycycline hyclate 20 mg tablet by mouth twice daily |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Males and females ages of 18 and up
- Atraumatic unilateral elbow pain of ≥ 6 weeks duration
- Diagnosed clinically as lateral or medial elbow tendinopathy
- Activity-related lateral or medial elbow pain
- Tenderness of the lateral or medial epicondyle
Key exclusion criteria (15 listed)
- Prior surgery of the affected elbow
- Prior injection of the affected lateral or medial epicondyle or extensor tendons
- Prior extracorporeal shockwave therapy to the affected elbow
- Suspicion for radial tunnel syndrome (tenderness distal to the lateral epicondyle in the area of the supinator muscle dorsally, pain with resisted supination with the elbow extended, and/or weakness of the extensor digitorum communis)
- Separate upper extremity injury or condition that would interfere with full participation in the home exercise program
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Doxycycline Hyclate 20 MGSubjects will receive doxycycline 20 mg BID | Drug | SD-doxycycline group |
Primary outcome
Primarily a feasibility study of SD-doxycycline as an adjunctive treatment for elbow tendinopathy (Compliance)
Time frame: 12 weeks
Compliance: At the end of the study, compliance will be calculated using the number of self-reported doses taken divided by the number of prescribed doses (twice daily x 7 days per week x 12 weeks = 168 doses).
Receptiveness
Time frame: 12 weeks
The number of patients who enroll in study divided by the number eligible patients minus the number of patients who decline due to reasons unrelated to the prescribed treatment, e.g., unable to return for second study visit. This will be measured at time of study recruitment.
5 secondary outcomes
Clinical outcomes - qDASH
Time frame: 12 weeks
Clinical outcomes - PRTEE
Time frame: 12 weeks
Secondarily, clinical outcomes will be measured to provide preliminary data to power a future randomized controlled trial. (Ultrasound tendinopathy grade)
Time frame: 12 weeks
Clinical outcomes - Grip strength
Time frame: 12 weeks
Clinical outcomes - MMP
Time frame: 12 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Apr 2026.
- Individual participant dataSharing planned: Yes. All individual participant data collected during the trial after deidentification
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Brett G Toresdahl, MD principal investigator
Hospital for Special Surgery, New York
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Doxycycline Hyclate 20 MG in people with Lateral Epicondylitis and Lateral Epicondylitis, Left Elbow, run by Hospital for Special Surgery, New York at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 28 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Primarily a feasibility study of SD-doxycycline as an adjunctive treatment for elbow tendinopathy (Compliance) (time frame: 12 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Apr 2026.