An open-label, long-term safety and tolerability trial of diclofenac sodium 1% gel in patients with knee osteoarthritis

Knee osteoarthritis: disease burden, available treatments, and emerging options

Osteoarthritis (OA) is a prevalent condition that affects nearly 528 million people worldwide, including 23% of the global population aged ⩾40, and is characterized by progressive damage to articular cartilage, which often leads to substantial pain, stiffness, and reduced mobility for affected patients. Pain related to OA is a barrier to maintaining physical activity and a leading cause of disability, accounting for 2.4% of all years lived with disability globally, reducing the ability to work in 66% of US patients with OA and increasing absenteeism in 21% of US patients with OA. The joint most commonly involved in OA is the knee, which is affected in about 60%-85% of all OA cases. The aging population and longer life expectancy, coupled with earlier and younger diagnoses, translate into a growing cohort of symptomatic patients in need of alternatives to surgery. Despite the large number of patients with knee OA (OAK) worldwide, the high degree of variability in patient presentation can lead to challenges in diagnosis and treatment. Multiple society guidelines recommend therapies for OAK, but departures from guidelines by healthcare professionals in clinical settings reflect a discordance between evidence-based treatment algorithms and routine clinical practice. Furthermore, disease-modifying pharmacotherapies are limited, and treatment for OAK often focuses solely on symptom relief, rather than underlying causes. In this narrative review, we summarize the patient journey, analyze current disease burden and nonsurgical therapy recommendations for OAK, and highlight emerging and promising therapies-such as cryoneurolysis, long-acting corticosteroids, and gene therapies-for this debilitating condition.

Drug Delivery Strategies and Nanozyme Technologies to Overcome Limitations for Targeting Oxidative Stress in Osteoarthritis

Oxidative stress is an important, but elusive, therapeutic target for osteoarthritis (OA). Antioxidant strategies that target oxidative stress through the elimination of reactive oxygen species (ROS) have been widely evaluated for OA but are limited by the physiological characteristics of the joint. Current hallmarks in antioxidant treatment strategies include poor bioavailability, poor stability, and poor retention in the joint. For example, oral intake of exogenous antioxidants has limited access to the joint space, and intra-articular injections require frequent dosing to provide therapeutic effects. Advancements in ROS-scavenging nanomaterials, also known as nanozymes, leverage bioactive material properties to improve delivery and retention. Material properties of nanozymes can be tuned to overcome physiological barriers in the knee. However, the clinical application of these nanozymes is still limited, and studies to understand their utility in treating OA are still in their infancy. The objective of this review is to evaluate current antioxidant treatment strategies and the development of nanozymes as a potential alternative to conventional small molecules and enzymes.

Electroacupuncture vs topical diclofenac sodium gel for patients with hand osteoarthritis: study protocol for a randomized controlled trial

Background

Hand osteoarthritis (OA) is a prevalent joint disorder and a great burden to both patients and society. While electroacupuncture (EA) and topical diclofenac sodium gel (DSG) are both currently used to treat OA, no head-to-head study of EA and topical DSG for hand OA exists. Thus, it remains unknown whether one intervention offers improved outcomes over the other. This study aims to compare the effects of EA and topical DSG in patients with hand OA.

Methods

A total of 108 participants with hand OA according to the American College of Rheumatology criteria will be recruited and randomly assigned to the EA group or topical DSG group with a 1:1 allocation ratio. Participants in the EA group will receive EA treatment thrice weekly for 4 weeks, followed by a 12-week follow-up. In the topical DSG group, topical DSG at a dose of 2 g over the affected joints per hand will be applied four times per day for 4 weeks. The outcomes will be measured at weeks 4, 8, and 16. The primary outcome will be the change in average overall finger joint pain intensity in the dominant hand from baseline to week 4. All outcome variables will be analyzed on an intention-to-treat principle. All statistical tests will be two-sided.

Discussion

This study will help determine which of the two treatment protocols, EA or topical DSG, is more effective for the clinical treatment of hand OA.

Trial registration ClinicalTrials.gov identifier: NCT04402047. Registered 16 May 2020, https://clinicaltrials.gov/ct2/show/NCT04402047

Survey of Australasian Renal and Rheumatology Specialists investigating topical NSAID use and adverse renal outcomes

INTRODUCTION

A survey investigated physician reported use, prescribing practices and adverse renal events of topical NSAIDs.

METHOD

This survey was sent to members of the Australian Rheumatology Association and the Australian and New Zealand Society of Nephrology.

RESULTS

Sixty physicians responded, 55% (n = 33) were nephrologists; 45% (n = 27) rheumatologists. Nearly all (n = 56, 93.3%) had managed at least one patient using topical NSAIDs, including those with an eGFR <45 mL/min (n = 55, 91.7%). Concern was expressed that patients may use topical NSAIDs without the physician's knowledge. The majority (n = 40, 66.6%) have prescribed (or recommended) a topical NSAID, slightly less in patients with a reduced eGFR <45 mL/min (n = 36, 60.0%). Participants would advise topical NSAIDs for osteoarthritis and musculoskeletal pain, though be mindful to monitor the renal function and blood pressure. There was a variance in comments in advising use in CKD (eGFR <45 mL/min) from avoidance in those with an eGFR <30 mL/min to minimal concern. Most respondents (n = 55, 91.7%) had not encountered an acute kidney injury (AKI) suspected from topical NSAID use. Of the five that did, three were thought to be an adverse renovascular event and two were uncertain. All patients had an eGFR <45 mL/min, all had recovery f their renal function with NSAID cessation.

DISCUSSION

Patients commonly use topical NSAIDs, often without the physician's knowledge. Most respondents would recommend their use in osteoarthritis and musculoskeletal pain, though with caution in CKD. While an AKI is uncommon due to topical NSAIDs, it may occur, especially in those with CKD.

Safety of Topical Non-steroidal Anti-Inflammatory Drugs in Osteoarthritis: Outcomes of a Systematic Review and Meta-Analysis

Objective

We aimed to assess the safety of topical non-steroidal anti-inflammatory drugs (NSAIDs) in the management of osteoarthritis (OA) in a systematic review and meta-analysis of randomized, placebo-controlled trials.

Methods

A comprehensive literature search was undertaken in the MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and Scopus electronic databases. Randomized, double-blind, placebo-controlled, parallel-group trials that assessed adverse events (AEs) with topical NSAIDs in patients with OA were eligible for inclusion. Authors and/or study sponsors were contacted to obtain the full report of AEs. The primary outcomes were overall severe and serious AEs, as well as the following MedDRA System Organ Class (SOC)-related AEs: gastrointestinal, vascular, cardiac, nervous system, skin and subcutaneous tissue, musculoskeletal and connective tissue.

Results

The search strategy identified 1209 records, from which 25 papers were included in the qualitative synthesis and 19 were included in the meta-analysis, after exclusions. Overall, more total AEs (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.04–1.29; I² = 0.0%) and more withdrawals due to AEs (OR 1.49, 95% CI 1.15–1.92; I² = 0.0%) were observed with topical NSAIDs compared with placebo. The same results were achieved with topical diclofenac, largely driven by an increase in skin and subcutaneous tissue disorders (OR 1.73, 95% CI 0.96–3.10), although the difference was not statistically significant compared with placebo. No significant difference in the odds for gastrointestinal disorders was observed between topical NSAIDs and placebo (OR 0.96, 95% CI 0.73–1.27).

Conclusions

Topical NSAIDs may be considered safe in the management of OA, especially with regard to low gastrointestinal toxicity. The use of topical NSAIDs in OA should be considered, taking into account their risk: benefit profile in comparison with other anti-OA treatments.

Electronic supplementary material

The online version of this article (10.1007/s40266-019-00661-0) contains supplementary material, which is available to authorized users.

[Pharmacological action and clinical outcome of newly developed NSAIDs patch, "LOQOA® tape"]

Topical non-steroidal anti-inflammatory drugs (NSAIDs) patches are indispensable for the treatment of musculoskeletal diseases, while they are considered less effective than oral NSAIDs. LOQOA^® tape is a tape-type patch containing esflurbiprofen (SFP) as a major active ingredient with potent cyclooxygenase inhibition and sufficient skin permeability. SFP patch (SFPP) showed higher percutaneous absorption rate, rapid pain relief, and potent anti-inflammatory efficacy comparing with existing NSAIDs patches in rat. SFPP showed dramatically higher synovial fluid and tissue concentration on SFP than that of flurbiprofen (FP) patch after single application to knee osteoarthritis (OA) patients. On the other hand, clinical dosage of SFPP was determined as not more than two patches a day from the estimation of systemic exposure to SFP of SFPP and oral FP. SFPP showed statistically significant differences in pain relief and all the other efficacy end points compared to inactive placebo or FP patch in knee OA patients. Efficacy on OA other than knee joint was also observed. In long-term study of SFPP, using up to two patches a day, a total of 201 patients was included and 161 patients achieved 52-week application. Among drug-related side effects, skin reaction at the application sites was observed in 46.8% and discontinued in 4.3%. Although gastro-intestinal reaction and abnormal changes in laboratory tests related to kidney function were observed as systemic drug-related side effects, most of them were mild in severity. SFPP, the new generation NSAIDs patch, would be one of effective options for the treatment of symptomatic OA patients.

The Long-Term Safety of S-Flurbiprofen Plaster for Osteoarthritis Patients: An Open-Label, 52-Week Study

Background and objectives

The newly developed S-flurbiprofen plaster (SFPP) is a tape-type patch that shows innovative percutaneous absorption. This study was designed to evaluate the safety of a long-term 52-week SFPP application to osteoarthritis (OA) patients.

Methods

This was a multi-center, open-label, uncontrolled prospective study that included 201 OA patients. SFPP at 40 mg/day was applied to the site of pain in 101 patients and at 80 mg/day (2 patches) in 100 patients at a total of 301 sites for 52 weeks. The affected sites assessed included the knee (192), lumbar spine (66), cervical spine (26), and others (17). Drug safety was evaluated by medical examination, laboratory tests, and examination of vital signs. Efficacy was evaluated by the patient’s and clinician’s global assessments and clinical symptoms.

Results

Most patients (80.1 %) completed the 52-week SFPP application. The majority of drug-related adverse events (AEs) included mild dermatitis at the application sites and occurred in 46.8 % of the sites. No photosensitive dermatitis was observed. Systemic AEs occurred in 9.0 % of the patients; a serious AE (gastric ulcer hemorrhage) occurred in one patient. No clinically significant changes in the laboratory tests and vital signs were observed. The efficacy evaluation showed an improvement from 2 weeks after the SFPP application, which continued during the 52 weeks’ treatment.

Conclusions

No apparent safety concerns were observed, even during the long-term SFPP application. Therefore, SFPP could be an additional pharmacotherapy in OA treatment.

Topical NSAIDs for chronic musculoskeletal pain in adults

BACKGROUND

Use of topical nonsteroidal anti-inflammatory drugs (NSAIDs) to treat chronic musculoskeletal conditions has become widely accepted because they can provide pain relief without associated systemic adverse events. This review is an update of 'Topical NSAIDs for chronic musculoskeletal pain in adults', originally published in Issue 9, 2012.

OBJECTIVES

To review the evidence from randomised, double-blind, controlled trials on the efficacy and safety of topically applied NSAIDs for chronic musculoskeletal pain in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and our own in-house database; the date of the last search was February 2016. We also searched the references lists of included studies and reviews, and sought unpublished studies by asking personal contacts and searching online clinical trial registers and manufacturers' web sites.

SELECTION CRITERIA

We included randomised, double-blind, active or inert carrier (placebo) controlled trials in which treatments were administered to adults with chronic musculoskeletal pain of moderate or severe intensity. Studies had to meet stringent quality criteria and there had to be at least 10 participants in each treatment arm, with application of treatment at least once daily.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and extracted data. We used numbers of participants achieving each outcome to calculate risk ratio and numbers needed to treat (NNT) or harm (NNH) compared to carrier or other active treatment. We were particularly interested to compare different formulations (gel, cream, plaster) of individual NSAIDs. The primary outcome was 'clinical success', defined as at least a 50% reduction in pain, or an equivalent measure such as a 'very good' or 'excellent' global assessment of treatment, or 'none' or 'slight' pain on rest or movement, measured on a categorical scale.

MAIN RESULTS

We identified five new studies for this update, which now has information from 10,631 participants in 39 studies, a 38% increase in participants from the earlier review; 33 studies compared a topical NSAID with carrier. All studies examined topical NSAIDs for treatment of osteoarthritis, and for pooled analyses studies were generally of moderate or high methodological quality, although we considered some at risk of bias from short duration and small size.In studies lasting 6 to 12 weeks, topical diclofenac and topical ketoprofen were significantly more effective than carrier for reducing pain; about 60% of participants had much reduced pain. With topical diclofenac, the NNT for clinical success in six trials (2343 participants) was 9.8 (95% confidence interval (CI) 7.1 to 16) (moderate quality evidence). With topical ketoprofen, the NNT for clinical success in four trials (2573 participants) was 6.9 (5.4 to 9.3) (moderate quality evidence). There was too little information for analysis of other individual topical NSAIDs compared with carrier. Few trials compared a topical NSAID to an oral NSAID, but overall they showed similar efficacy (low quality evidence). These efficacy results were almost completely derived from people with knee osteoarthritis.There was an increase in local adverse events (mostly mild skin reactions) with topical diclofenac compared with carrier or oral NSAIDs, but no increase with topical ketoprofen (moderate quality evidence). Reporting of systemic adverse events (such as gastrointestinal upsets) was poor, but where reported there was no difference between topical NSAID and carrier (very low quality evidence). Serious adverse events were infrequent and not different between topical NSAID and carrier (very low quality evidence).Clinical success with carrier occurred commonly - in around half the participants in studies lasting 6 to 12 weeks. Both direct and indirect comparison of clinical success with oral placebo indicates that response rates with carrier (topical placebo) are about twice those seen with oral placebo.A substantial amount of data from completed, unpublished studies was unavailable (up to 6000 participants). To the best of our knowledge, much of this probably relates to formulations that have never been marketed.

AUTHORS' CONCLUSIONS

Topical diclofenac and topical ketoprofen can provide good levels of pain relief beyond carrier in osteoarthritis for a minority of people, but there is no evidence for other chronic painful conditions. There is emerging evidence that at least some of the substantial placebo effects seen in longer duration studies derive from effects imparted by the NSAID carrier itself, and that NSAIDs add to that.

Efficacy and safety of diclofenac sodium 2% topical solution for osteoarthritis of the knee: a randomized, double-blind, vehicle-controlled, 4 week study

OBJECTIVE

Nonsteroidal anti-inflammatory drugs (NSAIDs) are standard therapy for osteoarthritis (OA). Topically applied NSAIDs reduce systemic exposure compared with oral NSAIDS, and European guidelines recommend their use. The NSAID diclofenac is available in a range of topical formulations. Diclofenac 1% gel and 1.5% four times daily and 2% twice daily (BID) solutions are approved to reduce pain from OA of the knee(s). The objective of this study was to investigate the efficacy and safety of diclofenac sodium 2% topical solution BID versus vehicle control solution for treating pain associated with OA of the knee.

RESEARCH DESIGN AND METHODS

A phase II, 4 week, randomized, double-blind, parallel-group, two-arm, vehicle-controlled study compared pain relief with diclofenac sodium 2% topical solution versus control (vehicle only) in patients aged 40 to 85 years with radiographically confirmed primary OA of the knee.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01119898.

MAIN OUTCOME MEASURES

The primary efficacy outcome was change from baseline to the final visit in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. Secondary outcomes included additional WOMAC subscales and patient global assessment of OA. Treatment-emergent adverse events (TEAEs), skin irritation, and vital signs were assessed and collected throughout the study.

RESULTS

Of 260 patients randomized, 259 received ≥1 dose of study drug. Significantly greater reductions in least-squares mean (standard error) WOMAC pain scores were observed for diclofenac-treated (-4.4 [0.4]) versus vehicle-treated patients (-3.4 [0.4]) at the final visit (p = 0.040). The most commonly reported TEAEs were administration site conditions. The vehicle-treated group experienced slightly more TEAEs than the active treatment group (38.8% vs. 31.5%). No serious adverse events were reported.

CONCLUSIONS

Administration of diclofenac sodium 2% topical solution BID resulted in significantly greater improvement in pain reduction in patients with OA of the knee versus vehicle control and was generally well tolerated.

Long-term tolerability of topical diclofenac sodium 1% gel for osteoarthritis in seniors and patients with comorbidities

Background

Adverse events associated with nonsteroidal anti-inflammatory drugs (NSAIDs) used to treat knee and hand osteoarthritis may be more frequent in certain patient populations. Topical NSAIDs, such as diclofenac sodium 1% gel (DSG), have equivalent efficacy and fewer adverse events compared with oral NSAIDs. This post hoc analysis assessed the long-term tolerability of DSG in elderly patients and patients with an elevated risk of gastrointestinal, cardiovascular, and renal adverse events.

Methods

Patients ≥ 35 years of age with knee osteoarthritis applied DSG (4 g) to one or both knees for 12 weeks during either of two primary studies and for 9 months during a long-term extension study. Other patients entered the long-term extension study directly and applied DSG for 12 months. Safety was assessed by reported adverse events. Subpopulations were defined based on age, or the comorbidities of hypertension, type 2 diabetes mellitus, and cerebrovascular or cardiovascular disease.

Results

The safety population consisted of 947 patients who received at least one dose of DSG during the primary or extension study. Patients aged < 65 years (68.2%) and ≥65 years (67.2%) experienced any adverse event at similar rates. The percentage of patients who experienced any adverse event was similar between patients with and without hypertension (65.5% versus 69.7%, respectively), type 2 diabetes mellitus (64.0% versus 68.2%), or cerebrovascular or cardiovascular disease (61.9% versus 68.5%). Among the 15 patients with all three comorbidities, the percentage of patients with any adverse event (53.3%) was less than that of patients who did not have all three comorbidities (68.0%).

Conclusion

These results suggest that long-term DSG treatment is safe in patient subpopulations with an elevated risk of NSAID-related adverse events, such as the elderly and those with the comorbidities of hypertension, type 2 diabetes mellitus, and cerebrovascular or cardiovascular disease.

Topical NSAIDs for chronic musculoskeletal pain in adults

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly taken orally, but they are also available in topical preparations to be applied to or rubbed onto the skin of a painful joint, typically one affected by arthritis, with the aim of relieving pain locally. Topical NSAIDs are widely used in some parts of the world for acute and chronic painful conditions, but have not been universally accepted until recently. One of the problems has been that older clinical studies were generally short, lasting four weeks or less, and short duration studies are not regarded as adequate in ongoing painful conditions.

OBJECTIVES

To examine the use of topical NSAIDs in chronic musculoskeletal pain, focusing on studies of high methodological quality, and examining the measured effect of the preparations according to study duration. The principal aim was to estimate treatment efficacy in longer duration studies of at least 8 weeks.

SEARCH METHODS

A series of electronic searches, together with bibliographic searches, and searches of in-house databases were combined with electronic searches of clinical trial registers and manufacturers of topical NSAIDs, or companies known to be actively researching topical NSAIDs. There had to be at least 10 participants in each treatment arm, with application of treatment at least once daily.

SELECTION CRITERIA

Randomised, double blind studies with placebo or active comparators, where at least one treatment was a topical NSAID product, in any topical formulation (cream, gel, patch, solution), in studies lasting at least two weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and validity, and extracted data. Numbers of participants achieving each outcome were used to calculate relative risk (RR) and numbers needed to treat (NNT) or harm (NNH) compared to placebo or other active treatment.

MAIN RESULTS

Information was available from 7688 participants in 34 studies from 32 publications; 23 studies compared a topical NSAID with placebo. Topical NSAIDs were significantly more effective than placebo for reducing pain due to chronic musculoskeletal conditions. The best data were for topical diclofenac in osteoarthritis, where the NNT for at least 50% pain relief over 8 to 12 weeks compared with placebo was 6.4 for the solution, and 11 for the gel formulation. There were too few data of good quality to calculate NNTs for other individual topical NSAIDs compared with placebo. Direct comparison of topical NSAID with an oral NSAID did not show any difference in efficacy. There was an increase in local adverse events (mostly mild skin reactions) with topical NSAIDs compared with placebo or oral NSAIDs, but no increase in serious adverse events. Gastrointestinal adverse events with topical NSAID did not differ from placebo, but were less frequent than with oral NSAIDs.A substantial amount of data from unpublished studies was unavailable. Much of this probably relates to formulations that have never been marketed.

AUTHORS' CONCLUSIONS

Topical NSAIDs can provide good levels of pain relief; topical diclofenac solution is equivalent to that of oral NSAIDs in knee and hand osteoarthritis, but there is no evidence for other chronic painful conditions. Formulation can influence efficacy. The incidence of local adverse events is increased with topical NSAIDs, but gastrointestinal adverse events are reduced compared with oral NSAIDs.