ROME — A 6-month regimen of dual antiplatelet therapy (DAPT) with clopidogrel was non-inferior to the practice of 18-month inhibition after stenting with a newer-generation drug-eluting device, the NIPPON study suggested.
In terms of adverse events — including all-cause death, myocardial infarction, cerebrovascular events, and major bleeding — the two DAPT strategies came out on par (1.92% for 6 months versus 1.45% for 18 months, lower limit of 95% CI -1.48 difference meeting the non-inferiority margin of -2.0), according to Masato Nakamura, MD, PhD, of Toho University Ohashi Medical Center in Tokyo, and colleagues.
However, NIPPON suffered from a slow trickle in enrollment that finally forced investigators to end up underpowered in their analysis. “The DAPT trial was published and moved the physicians to longer inhibition” during enrollment, Nakamura explained at a press conference at the European Society of Cardiology (ESC) annual meeting.
“The results need to be interpreted with caution given premature termination of enrollment, an open-label design with frequent crossover, and a wide non-inferiority margin,” he concluded.
“Neither of the treatment arms was an accepted reference strategy at the time of initiation of the trial. Both were in sense experimental arms,” pointed out ESC session discussant Philippe G. Steg, MD, of Hôpital Bichat-Claude Bernard in Paris.
While he added that NIPPON’s event rates were surprisingly low, he lauded the authors for their “huge effort” — likely underfunded — involving many patients and many years of work.
The issues that plagued this DAPT study are common in the literature, Steg noted, adding that while underpowered trials can be pooled, bias cannot be eliminated this way.
“We don’t have the support and funding for properly blinded trials [on DAPT],” he emphasized. “This is a call for better public funding of these studies. If you don’t have the resources, you can’t conduct trials without bias.”
Nakamura and colleagues analyzed data from 2,772 patients who completed 18-month follow-up (out of 3,775 total participants) at 130 Japanese institutions. Patients received the Nobori stent, which features a bioabsorbable polymer and abluminal coating. Baseline characteristics were similar between groups.
Rates of bleeding were similar at 18 months (0.96% for 6-month versus 0.73% for 18-month DAPT), as were the rates of stent thrombosis (0.07% for both).
Nakamura disclosed relevant relationships with Terumo, Daiichi Sankyo, Sanofi, and AstraZeneca.
Steg disclosed multiple relevant relationships with industry including AstraZeneca Pharmaceuticals, Bayer HealthCare Pharmaceuticals, CSL Behring, Daiichi Sankyo, GlaxoSmithKline, Janssen Pharmaceuticals, Lilly, Novartis Pharmaceuticals, Pfizer, Regeneron Pharmaceuticals, Sanofi, and The Medicines Company.
European Society of Cardiology
Nakamura M, et al “6 months versus 18 months dual antiplatelet treatment for patients underwent bioabsorbable polymer and abluminal coated DES deployment: NIPPON randomized study” ESC 2016.