乌鸦传媒

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A subanalysis of data from the 10,000-patient CANTOS study provides significant evidence of the cardiovascular benefit of anti-inflammatory treatment with the monoclonal antibody canakinumab.

"This [analysis] confirms the mechanism of action," said Paul M. Ridker, MD, who led the CANTOS investigators. "Independent of other risk factors -- age, comorbidities, gender, race -- the benefit tracks the reduction in IL-6 and C-reactive protein."

This prespecified analysis follows the report of the full CANTOS findings at the ESC meeting in Barcelona last August. The results of this new analysis were published online in and presented as a late-breaking trial at the meeting in Anaheim.

When the response to the drug was "robust," which Ridker defined as roughly a 50% reduction in inflammatory markers, the "all cause mortality and cardiovascular mortality were reduced by 31%." Even patients who had a "less robust response" showed some benefit, but that minimal response would make it difficult to justify using a drug which is estimated to cost as much as $200,000 a year.

But the key consideration, according to Ridker, is the response. Among responders, the number needed to treat for 5 years to achieve benefit drops to 16 compared with 57 among less robust responders. In the CANTOS trial roughly half of the 10,061 patients, all of whom had a history of myocardial infarction, were robust responders, meaning that their highly sensitive (hs) CRP value was reduced to less than 2 mg/L.

He told 乌鸦传媒 that the difference in response pointed to an opportunity for "personalized medicine" since responders can be identified after a single dose.

"If a patient responds, continue the drug," he said. Following that algorithm, he suggested that the drugmaker -- Novartis -- might want to consider making the first dose free.

Patients in CANTOS were randomized to one of three canakinumab doses (50 mg, 150 mg, or 300 mg) or placebo given subcutaneously once every 3 months.

In a commentary, also published online by The Lancet, Erin D. Michos, MD, and Roger S. Blumenthal, MD, of the Ciccarone Center for the Prevention of Cardiovascular Disease at Johns Hopkins School of Medicine, pointed out that there remain some unanswered questioned about the CANTOS results.

"First, since everyone in CANTOS had a hsCRP of 2 mg/L or higher at baseline, the effect of canakinumab in people with lower baseline hsCRP remains unknown. Second, the median follow-up time was relatively short (3.7 years), and the relative benefit and risk [of infection] of longer term therapy is uncertain," they wrote.

Ridker noted that the findings had limitation including the fact that because this was an on-treatment analysis, the observations were not "formally randomized and could reflect, in part, differences in baseline clinical characteristics that associate with reduced on-treatment hs-CRP concentrations."

Moreover, since the study entry criteria required elevated hsCRP at baseline, the benefit of canakinumab treatment may only apply to persons with elevated hsCRP. And, finally, although the results point to a benefit for reducing inflammation those benefits may not extend to other anti-inflammatory therapies. To address that broader issue, there are ongoing trials of methotrexate and colchicine.