Elliot W. Ehrich

Characterization of rofecoxib as a cyclooxygenase‐2 isoform inhibitor and demonstration of analgesia in the dental pain model

Nonsteroidal anti‐inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and indomethacin (INN, indometacin) inhibit both the constitutive (COX‐1) and inducible (COX‐2) isoforms of cyclooxygenase. The induction of COX‐2 after inflammatory stimuli has led to the hypothesis that COX‐2 inhibition primarily accounts for the therapeutic properties of NSAIDs.

Rofecoxib, a specific inhibitor of cyclooxygenase 2, with clinical efficacy comparable with that of diclofenac sodium: Results of a one-year, randomized, clinical trial in patients with osteoarthritis of the knee and hip

OBJECTIVE To compare the clinical efficacy of rofecoxib, a specific inhibitor of cyclooxygenase 2 (COX-2), with that of diclofenac in patients with osteoarthritis (OA) and to evaluate the safety and tolerability of rofecoxib. METHODS We performed a randomized, double-blind, active comparator-controlled trial in 784 adults with OA of the knee or hip. Patients were randomized to 1 of 3 treatment groups: 12.5 mg of rofecoxib once daily, 25 mg of rofecoxib once daily, and 50 mg of diclofenac 3 times daily. Clinical efficacy and safety were evaluated over a 1-year continuous treatment period. RESULTS Rofecoxib at dosages of 12.5 and 25 mg demonstrated efficacy that was clinically comparable to that of diclofenac, as assessed by all 3 primary end points according to predefined comparability criteria. Results from secondary end points were consistent with those of the primary end points. There were small statistical differences favoring diclofenac for 2 of the end points. All treatments were well tolerated. CONCLUSION Rofecoxib was well tolerated and provided efficacy that was clinically comparable, according to predefined statistical criteria, to that of 150 mg of diclofenac per day in this 1-year study. Specific inhibition of COX-2 provided therapeutic efficacy in OA.

The safety profile, tolerability, and effective dose range of rofecoxib in the treatment of rheumatoid arthritis

Nonsteroidal anti-inflammatory drugs. (NSAIDs) inhibit both cyclooxygenase (COX)-1 and COX-2 isoenzymes and are effective in the treatment of inflammatory disorders. This 8-week, double-masked, placebo-controlled trial was undertaken to assess the safety profile, tolerability, and effective dose range of once-daily rofecoxib, a COX-2-specific inhibitor, in the treatment of rheumatoid arthritis (RA). After a 3- to 15-day washout of prior NSAID therapy, 658 patients were randomly allocated to receive placebo or rofecoxib 5 mg, 25 mg, or 50 mg once daily. Safety profile, tolerability, and efficacy were evaluated after 2, 4, and 8 weeks of therapy. Six hundred fifty-eight patients (168, 158, 171, and 161 in the placebo and 5-mg, 25-mg, and 50-mg rofecoxib groups, respectively) were enrolled at 79 clinical centers in the United States. Mean age was 55 years, mean duration of RA was 10 years, and 506 (77%) of the 658 patients were female. All groups had similar baseline demographic characteristics. Patients taking rofecoxib 25 and 50 mg showed significant clinical improvement compared with those taking placebo; 43.9% in the rofecoxib 25-mg group and 49.7% in the rofecoxib 50-mg group completed the treatment period and achieved an American College of Rheumatology 20 response (P = 0.025 and 0.001 vs. placebo, respectively). The 5-mg dose of rofecoxib did not differ significantly from placebo. Patients in the rofecoxib 25- and 50-mg groups showed significant improvement in key individual efficacy measurements, including patient global assessment of pain, patient and investigator global assessment of disease activity, and Stanford Health Assessment Questionnaire Disability Index (P<0.05 vs placebo). Compared with placebo, significantly fewer patients in the 25-mg and 50-mg rofecoxib groups discontinued therapy because of lack of efficacy (P = 0.02 and P = 0.032, respectively). Our results show that rofecoxib 25 and 50 mg once daily was effective and generally well-tolerated in patients with RA.

Pharmacokinetics, COX-2 specificity, and tolerability of supratherapeutic doses of rofecoxib in humans.

AbstractObjective: Prostaglandin synthesis is catalyzed by a constitutive cyclo-oxygenase isoform (COX-1) and an inducible isoform (COX-2). It is hypothesized that the analgesic and anti-inflammatory effects of nonsteroidal anti-inflammatory drugs (nonspecific COX-1/COX-2 inhibitors) such as ibuprofen principally derive from COX-2 inhibition. The purpose of this study was to evaluate steady-state pharmacokinetics, biochemical selectivity and tolerability of rofecoxib (VioxxTM), characterized in vitro as a COX-2 inhibitor. Methods: Four panels of healthy men (n=8 per panel) were administered rofecoxib (n=6) (25, 100, 250, 375 mg) or placebo (n=2) once daily on day 1 and days 3–14. Blood samples for assays of rofecoxib plasma concentration and COX isoform activity were obtained pre-dose and at specified time points post-dose. Results: Rofecoxib pharmacokinetics were found to be complex and nonlinear. Elimination half-life ranged from 9.9 h to 17.5 h after multiple dosing with an accumulation ratio close to 2 for all doses. COX-2 inhibitory activity as assessed by average inhibition of whole blood lipopolysaccharide-stimulated prostaglandin E2 over the 8-h post-dose period on day 14 was 0.3, 67, 96, 92 and 96% for the placebo and the 25-, 100-, 250- and 375-mg treatment groups, respectively. No treatment group showed significant inhibition of COX-1 as assessed by thromboxane B2 generation in clotting whole blood. Side effects were mild and transient. Conclusion: The results indicate that rofecoxib is a potent and specific inhibitor of COX-2 in humans even at doses more than tenfold higher than those associated with efficacy in patients with osteoarthritis.

A multicenter, randomized, controlled trial to evaluate the safety profile, tolerability, and efficacy of rofecoxib in advanced elderly patients with osteoarthritis.

This 6- week study was conducted to test the efficacy, safety, and tolerability of rofecoxib (a selective COX- 2 inhibitor) compared to nabumetone (a non- selective NSAID) and placebo in osteoarthritis (OA) patients aged 80 and older. Three hundred forty- one patients, mean age 83 years, were randomized. Allocations were made in an approximately 1:2:1:2 ratio (placebo: 12.5 mg rofecoxib: 25 mg rofecoxib: 1500 mg nabumetone). Least square mean changes from baseline in the primary efficacy endpoint, Patient Global Assessment of Disease Status, were as follows (with negative numbers indicating improvement): - 14.85 mm for placebo; - 25.34 mm for 12.5 mg rofecoxib; - 25.40 mm for 25 mg of rofecoxib; and - 25.95 mm for nabumetone ( p<0.001 for all active treatments vs placebo.) Results from secondary end- points, including the 3 WOMAC sub- scales (pain, stiffness, and disability) and the Investigator Global Assessment of Disease Status, were consistent with those for the primary endpoint. No significant between- group differences were observed in the proportions of patients who discontinued treatment due to either clinical or laboratory adverse experiences. Renal safety (edema and hypertension adverse experiences) was similar for rofecoxib and nabumetone. No gastroduodenal ulcers occurred; however, the demonstration of gastrointestinal risk with rofecoxib or nabumetone was beyond the scope of this trial. We conclude that in patients 80 years and older, rofecoxib, 12.5 mg and 25 mg once daily, demonstrated clinical efficacy for the treatment for OA as did 1500 mg of nabumetone. Rofecoxib and nabumetone were generally well tolerated in this elderly population.

Dose-effect relationships of nonsteroidal anti-inflammatory drugs: a literature review

BACKGROUND Many clinicians believe that higher doses of nonsteroidal anti-inflammatory drugs (NSAIDs) are more effective than lower doses for the treatment of rheumatoid arthritis (RA) and osteoarthritis (OA) but are associated with higher rates of adverse events (AEs). However, there is a lack of consensus on dose-effect relationships with the NSAIDs. OBJECTIVE The purpose of this review was to investigate evidence for the relationship between NSAID dose, efficacy, and the occurrence of AEs from clinical trials of RA and OA of the hip and knee. METHODS Relevant English-language publications were identified through a search of EMBASE, MEDLINE, and REFLINE using the terms aceclofenac, diclofenac, etodolac, ibuprofen, isoxicam, lornoxicam, meloxicam, nabumetone, naproxen, piroxicam, tenidap, tenoxicam, arthritis, OA (hip and knee), RA, rheumatic disorders, and musculoskeletal disorders for the period January 1970 to December 1997 (this review was conducted in 1998). Bibliographies of retrieved publications were reviewed for other potentially relevant articles. Selected publications were evaluated for quality (likelihood of bias) based on 4 factors (randomization procedure; completeness of patient and treatment information; standardization and completeness of outcome data; and reporting of attrition data). RESULTS This review included 99 publications concerning clinical trials conducted in 24 countries and enrolling 28,239 patients. The majority of reports were published in the 1990s, particularly in the latter half of that decade. The average quality of the publications improved over time, with a significant increase in mean quality score from 5.43 in the 1970s to 9.21 during the last half of the 1990s (P < 0.05). Only 8 reports directly compared high and low doses of the same drug in relation to efficacy. CONCLUSIONS Data on the relationship of NSAID dose to efficacy and the incidence of AEs were limited. There is a need for clinical trials directly addressing dose-effect relationships of NSAIDs, as well as reviews of more current literature and reports in languages other than English.

Demonstration of specific COX‐2 inhibition by MK‐966 in humans with supratherapeutic doses

Clinical Pharmacology & Therapeutics (1999) 65, 164–164; doi: