Repatha Non-Responder Profile: Who Doesn't Get Full LDL Reduction?

What does a full response to Repatha look like?

In FOURIER, 27,564 adults with atherosclerotic cardiovascular disease and LDL-C of 70 mg/dL or higher on a statin received evolocumab 140 mg every 2 weeks (86%) or 420 mg monthly. At 48 weeks the LDL-C reduction versus placebo was 59%, taking the median from 92 mg/dL to 30 mg/dL [2]. The Repatha label describes the same trial as a 63% difference at week 12 and 57% at week 72, with a median of 26 mg/dL at week 48 and 47% of patients below 25 mg/dL [3][2].

Against a statin background in LAPLACE-2 (1,896 patients), the label reports LDL-C differences of 71% for 140 mg every 2 weeks and 63% for 420 mg monthly versus placebo, and 45% and 41% versus ezetimibe 10 mg [3]. In VESALIUS-CV, which enrolled people with atherosclerosis or diabetes and no prior heart attack or stroke, the week-48 difference was 53% [4].

These results describe average LDL-C changes, not how many individual patients had little or no reduction.

What is the response in homozygous familial hypercholesterolemia?

TESLA Part B randomized 50 patients with HoFH, aged 12 and older, to evolocumab 420 mg or placebo every 4 weeks for 12 weeks; 49 received study drug (33 evolocumab, 16 placebo). At week 12, LDL-C measured by ultracentrifugation was 30.9% lower with evolocumab than with placebo (95% CI -43.9 to -18.0) [1]. An earlier pilot study of evolocumab in HoFH had produced a 16% reduction, which the same paper cites [1].

FOURIER's 59% came from a different population, adults with established atherosclerotic disease on a statin [2], so the two numbers describe different groups and are not a head-to-head comparison.

The paper describes HoFH as a disorder of very low or absent plasma clearance of LDL in which conventional lipid-lowering treatment is only modestly effective [1]. Evolocumab binds PCSK9 and leaves more LDL receptors available to clear LDL from the blood [3]. For HoFH, the label starts treatment at 420 mg once monthly and allows an increase to 420 mg every 2 weeks if a clinically meaningful response is not achieved in 12 weeks [3]. Patients on lipid apheresis may start at 420 mg every 2 weeks, given after the apheresis session [3].

In heterozygous FH, RUTHERFORD-2 randomized 331 patients, and both evolocumab schedules lowered LDL-C significantly more than placebo at week 12 [5].

Do antibodies to evolocumab explain a weak response?

In the trial data, antibodies were rare and did not affect response. Of 17,992 adults tested, 48 (0.3%) developed binding antibodies to evolocumab. None were neutralizing, and the label states there was no evidence of an effect on pharmacokinetics, response or safety. No antibodies were detected in pediatric trials [3].

Does a statin change evolocumab exposure?

The Repatha label has no drug-interactions section [3]. In adults on a high-intensity statin, evolocumab Cmax and AUC were about 20% lower, a difference the label calls not clinically meaningful [3]. Evolocumab is eliminated by target binding and proteolysis, and age, sex, race and creatinine clearance did not affect its pharmacokinetics [3].

Are dose changes needed for kidney or liver problems?

The label recommends no dose adjustment for renal impairment or for mild to moderate hepatic impairment [3]. In mild to moderate hepatic impairment, Cmax was 20 to 30% lower and AUC 40 to 50% lower; in severe renal impairment or hemodialysis, exposure was lower while PCSK9 reduction was similar [3].

When should LDL-C be measured?

The label says the LDL-lowering effect of Repatha may be measured as early as 4 weeks after starting treatment, and with the monthly regimen the label specifies measuring just before the next dose [3]. Maximum LDL-C reduction occurred by 2 weeks after a 140 mg dose and by 3 weeks after 420 mg; trough levels approached steady state by 12 weeks; the effective half-life is 11 to 17 days [3].

What the label says to watch for

The only warning and precaution is hypersensitivity, including angioedema; the label says to stop treatment and treat if serious symptoms occur [3]. A history of serious hypersensitivity to evolocumab or an excipient is a contraindication [3]. In pooled controlled trials, hypersensitivity reactions occurred in 5.1% on evolocumab versus 4.7% on placebo, and injection-site reactions in 3.2% versus 3.0% [3]. In the 52-week trial, myalgia was 4.0% versus 3.0% [3].

Putting it together

The LDL-C difference versus placebo was 30.9% in the HoFH trial [1] and 59% in FOURIER [2]. For HoFH, the label builds in a 12-week response check with a dose increase [3]. Binding antibodies occurred in 0.3% of adults, none neutralizing [3].