Does Exist a Differential Impact of Degarelix Versus LHRH Agonists on Cardiovascular Safety? Evidences From Randomized and Real-World Studies

The main systemic therapy for the management of hormone-sensitive prostate cancer (PC) is androgen deprivation therapy (ADT), with the use of long-acting luteinizing hormone releasing-hormone (LHRH) agonists considered the main form of ADT used in clinical practice to obtain castration in PC. The concomitant administration of antiandrogens for the first weeks could reduce the incidence of clinical effects related to the testosterone flare-up in the first injection of LHRH. On the contrary, Gonadotropin Rh (GnRH) antagonists produce a rapid decrease of testosterone levels without the initial flare-up, with degarelix commonly used in clinical practice to induce castration in PC patients. Even if no long-term data are reported in terms of survival to define a superiority of GnRH or LHRH, for oncological efficacy and PC control, data from randomized clinical trials and from real-life experiences, suggest a difference in cardiovascular risk of patients starting ADT. The age-related decline in testosterone levels may represent a factor connected to the increase of cardiovascular disease risk, however, the role of ADT in increasing CV events remains controversial. For these reasons, the aim of the paper is to synthesize the difference in cardiovascular risk between LHRH and degarelix in patients undergoing ADT. A difference in cardiovascular risk could be indeed an important parameter in the evaluation of these two forms of castration therapy. The Randomized trials analyzed in this paper sustain a possible protective role for degarelix versus LHRH agonists in reducing the rate of new CV events and interventions in the short-term period. On the contrary, real-word data are contradictory in different national experiences and are strongly conditioned by huge differences between the LHRH agonists group and the degarelix group.

[Cardiovascular risk patients under androgen deprivation therapy: Lower risk with GnRH antagonists compared to LHRH agonists?]

BACKGROUND

Androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists or GnRH antagonists is the mainstay of treatment for metastatic prostate cancer (mCaP). However, ADT is associated with serious cardiovascular events. Only a few studies that directly compare the cardiovascular risk of LHRH agonists versus GnRH antagonists have been published.

OBJECTIVES

This review aims to compare the cardiovascular risk of LHRH agonists versus GnRH antagonists based on the literature.

METHODS

A literature search that considered full publications and abstracts published before December 10, 2014 was performed. Due to their high evidence quality, only meta-analyses and pooled studies were included in this review.

RESULTS

Four studies were included. These investigated the cardiovascular risk of patients receiving an ADT with LHRH agonists and/or GnRH antagonists. However, only one of these directly compared the cardiovascular risk of ADT with LHRH agonists versus GnRH antagonists. This meta-analysis showed a significant reduction in cardiovascular risk for patients receiving a GnRH antagonist compared to those patients receiving a LHRH agonist (HR: 0.597; 95 % CI: 0.380-0.938; P = 0.0253). Subgroup analyses showed that, in particular, patients with pre-existing cardiovascular diseases who were treated with a GnRH antagonist have a significantly lower risk of experiencing a cardiovascular event when compared with patients receiving a GnRH agonist (HR: 0.44; 95 % CI: 0.26-0.74; P = 0.002).

CONCLUSION

In conclusion, GnRH antagonists are associated with a lower risk of cardiovascular events, compared with LHRH agonists, when administered as ADT in CaP patients, and particularly in patients with a history of cardiovascular disease. Thus, patients with a history of cardiovascular disease may benefit from ADT with a GnRH antagonist.