Combination therapy with etanercept and anakinra in the treatment of patients with rheumatoid arthritis who have been treated unsuccessfully with methotrexate

OBJECTIVE

To determine the potential for additive or synergistic effects of combination therapy with the selective anti-tumor necrosis factor alpha agent etanercept and the anti-interleukin-1 agent anakinra.

METHODS

Two hundred forty-four patients in whom rheumatoid arthritis (RA) was active despite methotrexate therapy were treated with subcutaneous etanercept only (25 mg twice weekly), full-dosage etanercept (25 mg twice weekly) plus anakinra (100 mg/day), or half-dosage etanercept (25 mg once weekly) plus anakinra (100 mg/day) for 6 months in a double-blind study at 41 centers in the US. Patients had never previously received anticytokine therapy. Patient response was measured with the American College of Rheumatology (ACR) core set criteria, a health-related quality-of-life questionnaire, and the Disease Activity Score. Safety was assessed by the number of adverse events and clinical laboratory values. Plasma concentrations of both agents and antibody formation against both agents were also assessed.

RESULTS

Combination therapy with etanercept plus anakinra provided no treatment benefit over etanercept alone, regardless of the regimen, but was associated with an increased safety risk. Thirty-one percent of the patients treated with full-dosage etanercept plus anakinra achieved an ACR 50% response, compared with 41% of the patients treated with etanercept only. This result was not statistically significant (P = 0.914). The incidence of serious infections (0% for etanercept alone, 3.7-7.4% for combination therapy), injection-site reactions, and neutropenia was increased with combination therapy. Combination therapy had no effect on the pharmacokinetics or immunogenicity of either agent.

CONCLUSION

Combination therapy with etanercept and anakinra provides no added benefit and an increased risk compared with etanercept alone and is not recommended for the treatment of patients with RA.

Exercise exacerbates acute mountain sickness at simulated high altitude

We hypothesized that exercise would cause greater severity and incidence of acute mountain sickness (AMS) in the early hours of exposure to altitude. After passive ascent to simulated high altitude in a decompression chamber [barometric pressure = 429 Torr, approximately 4,800 m (J. B. West, J. Appl. Physiol. 81: 1850-1854, 1996)], seven men exercised (Ex) at 50% of their altitude-specific maximal workload four times for 30 min in the first 6 h of a 10-h exposure. On another day they completed the same protocol but were sedentary (Sed). Measurements included an AMS symptom score, resting minute ventilation (VE), pulmonary function, arterial oxygen saturation (Sa(O(2))), fluid input, and urine volume. Symptoms of AMS were worse in Ex than Sed, with peak AMS scores of 4.4 +/- 1.0 and 1.3 +/- 0.4 in Ex and Sed, respectively (P < 0.01); but resting VE and Sa(O(2)) were not different between trials. However, Sa(O(2)) during the exercise bouts in Ex was at 76.3 +/- 1.7%, lower than during either Sed or at rest in Ex (81.4 +/- 1.8 and 82.2 +/- 2.6%, respectively, P < 0.01). Fluid intake-urine volume shifted to slightly positive values in Ex at 3-6 h (P = 0.06). The mechanism(s) responsible for the rise in severity and incidence of AMS in Ex may be sought in the observed exercise-induced exaggeration of arterial hypoxemia, in the minor fluid shift, or in a combination of these factors.