Translating the benefits
Ulrich Laufs, MD, Leipzig (Germany) University Hospital, Germany, and invited commentator for the session, said the trial addresses two key issues: the long-term safety of low LDL cholesterol lowering and the long-term safety of inhibiting PCSK9, which is highly expressed not only in the liver but also in the brain, small intestine, and kidneys. Indeed, an LDL cholesterol level below 30 mg/dL is lower than the ESC treatment recommendation for very-high-risk patients and is, in fact, lower than most assays are reliable to interpret.
“So it is very important that we have these very clear data showing us that there were no adverse events, also including cataracts and hemorrhagic stroke, and these were on the level of placebo and did not increase over time,” he said.
The question of efficacy is triggered by observations of another PCSK9, the humanized monoclonal antibody bococizumab, which was associated in the SPIRE trial with an increase in LDL cholesterol over time because of neutralizing antibodies. Reassuringly, there was “completely sustained LDL [cholesterol] reduction” with no neutralizing antibodies with the fully human antibody evolocumab in FOURIER-OLE and in recent data from the OSLER-1 study, Dr. Laufs observed.
Acknowledging the potential for selection bias with an OLE program, Dr. Laufs said there are two important open questions: “Can the safety data observed for extracellular PCSK9 inhibition using an antibody be transferred to other mechanisms of PCSK9 inhibition? And obviously, from the perspective of patient care, how can we implement these important data into patient care and improve access to PCSK9 inhibitors?”
With regard to the latter point, he said physicians should be cautious in using the term “plaque regression,” opting instead for prevention and stabilization of atherosclerosis, and when using the term “legacy,” which may be misinterpreted by patients to imply there was cessation of therapy.
“From my perspective, [what] the open-label extension really shows is that earlier treatment is better,” Dr. Laufs said. “This should be our message.”
In a press conference prior to the presentation, ESC commentator Johann Bauersachs, MD, Hannover (Germany) Medical School, said “this is extremely important data because it confirms that it’s safe, and the criticism of the FOURIER study that mortality, cardiovascular mortality, was not reduced is now also reduced.”
Dr. Bauersachs said it would have been unethical to wait 7 years for a placebo-controlled trial and questioned whether data are available and suggestive of a legacy effect among patients who did not participate in the open-label extension.
Dr. O’Donoghue said unfortunately those data aren’t available but that Kaplan-Meier curves for the primary endpoint in the parent trial continued to diverge over time and that there was somewhat of a lag in terms of that divergence. “So, a median follow-up of 2 years may have been insufficient, especially for the emerging cardiovascular mortality that took longer to appear.”
The study was funded by Amgen. Dr. O’Donoghue reported receiving research grants from Amgen, AstraZeneca, Janssen, Intarcia, and Novartis, and consulting fees from Amgen, Novartis, AstraZeneca, and Janssen. Dr. Laufs reported receiving honoraria/reimbursement for lecture, study participation, and scientific cooperation with Saarland or Leipzig University, as well as relationships with multiple pharmaceutical and device makers.
A version of this article first appeared on Medscape.com.