A safety and clinical efficacy analysis of PCSK9 monoclonal antibodies in patients with markedly elevated creatine phosphokinase levels.

INTRODUCTION

PCSK9 inhibitors (PCSK9i) are often used in statin-intolerant patients, aiming to reduce low-density lipoprotein cholesterol (LDL-C). Along with the growing experience with their use, there is a lack of evidence regarding the safety, tolerability, and clinical utility of PCSK9i in patients with markedly elevated creatine phosphokinase (CPK) levels.

METHODS

We screened a comprehensive HMO database for patients treated with PCSK9i (Jan 2016-Dec 2019), in whom elevated CPK levels (>1,000 U/L) were documented prior to the initiation of therapy. Treatment plans, adherence, and the levels of CPK and LDL-C were analyzed.

RESULTS

Of the 1,600 patients initiating treatment with PCSK9i, 26 had prior CPK values >1,000 U/L [median (IQR): 3,687 (1,876-8,344) U/L]. All 26 patients were previously treated with statins, which presumably resulted in adverse effects (myalgia in 24, and rhabdomyolysis in 5 patients) therefore mandating their discontinuation. Concomitant secondary factors for CPK elevation were present in 11 patients, and included renal failure, rheumatoid disorders, hypothyroidism, intensive exercise, proteinuria and genetic muscular disease. Of the 26 patients treated with PCSK9i, alirocumab was administered to 12 patients, and evolocumab to 14. Following the initiation of treatment with either drug, 24 patients (92%) demonstrated a reduction in CPK of >50%, and in 12 (46%) CPK levels have returned to normal values. With regard to treatment goals, 17 patients (65%) have achieved an LDL-C level of <70 mg/dL, and 12 (46%) have reached a level of <55 mg/dL. No serious adverse reactions were documented, and only 2 patients discontinued the treatment (not due to muscle symptoms or CPK elevation).

CONCLUSIONS

PCSK9i constitute a safe, tolerable, and effective treatment for hyperlipidemia in patients with markedly elevated CPK. While statin intolerance is a major cause for CPK elevation, concomitant etiologies for increased CPK values were rather common.