Arterial thrombosis with immunomodulatory derivatives in the treatment of multiple myeloma: a single-center case series and review of the literature

Increased risk of arterial thromboembolic events with combination lenalidomide/dexamethasone therapy for multiple myeloma

INTRODUCTION

Cancer associated thrombosis is a leading cause of morbidity and mortality. Research and guidelines have focused on venous thromboembolic events (VTE). Within the past decade, combination lenalidomide and dexamethasone has become a standard of therapy for multiple myeloma and is now widely used. In these patients, the risk of arterial thromboembolic events (ATE) has not been addressed to the same extent as VTE. Areas discussed: Presented is a targeted review of published data on ATE in MM patients on combination lenalidomide/dexamethasone therapy. Incidence, clinical presentations, prognosis, mechanisms and thromboprophylaxis are discussed. A framework for approaching ATE/VTE in these patients is suggested. Expert commentary: There is an increased incidence of ATE in this population, primarily cerebrovascular and cardiovascular events. ATE is associated with poorer prognosis and its prevention must be an important goal of management. It is suggested that on initiating treatment, a combined VTE/ATE risk assessment should be performed and thromboprophylaxis initiated for a minimum of 6 months. As newer immunomodulatory therapies are developed, thromboembolic risk must be assessed early on. Further studies are needed to determine the optimal strategy to reducing both VTE and ATE in this population.

Thalidomide and dexamethasone vs. bortezomib and dexamethasone for melphalan refractory myeloma: a randomized study

OBJECTIVES

Thalidomide and bortezomib have been frequently used for second-line therapy in patients with myeloma relapsing after or refractory to initial melphalan-based treatment, but no randomized trials have been published comparing these two treatment alternatives.

METHODS

Thalidomide- and bortezomib-naïve patients with melphalan refractory myeloma were randomly assigned to low-dose thalidomide + dexamethasone (Thal-Dex) or bortezomib + dexamethasone (Bort-Dex). At progression on either therapy, the patients were offered crossover to the alternative drug combination. An estimated 300 patients would be needed for the trial to detect a 50% difference in median PFS between the treatment arms.

RESULTS

After inclusion of 131 patients, the trial was prematurely closed because of low accrual. Sixty-seven patients were randomized to Thal-Dex and 64 to Bort-Dex. Progression-free survival was similar (median, 9.0 months for Thal-Dex and 7.2 for Bort-Dex). Response rate was similar (55% for Thal-Dex and 63% for Bort-Dex), but time to response was shorter (P < 0.05) and the VGPR rate higher (P < 0.01) for Bort-Dex. Time-to-other treatment after crossover was similar (median, 13.2 months for Thal-Dex and 11.2 months for Bort-Dex), as was overall survival (22.8 months for Thal-Dex and 19.0 for Bort-Dex). Venous thromboembolism was seen in seven patients and cerebrovascular events in four patients in the Thal-Dex group. Severe neuropathy, reactivation of herpes virus infections, and mental depression were more frequently observed in the Bort-Dex group. In the quality-of-life analysis, no difference was noted for physical function, pain, and global quality of life. Fatigue and sleep disturbances were significantly more prevalent in the Bort-Dex group.

CONCLUSIONS

Thalidomide (50-100 mg daily) in combination with dexamethasone seems to have an efficacy comparable with that of bortezomib and dexamethasone in melphalan refractory myeloma. However, the statistical strength of the results in this study is limited by the low number of included patients.

The rise, fall and subsequent triumph of thalidomide: lessons learned in drug development

Perhaps no other drug in modern medicine rivals the dramatic revitalization of thalidomide. Originally marketed as a sedative, thalidomide gained immense popularity worldwide among pregnant women because of its effective anti-emetic properties in morning sickness. Mounting evidence of human teratogenicity marked a dramatic fall from grace and led to widespread social, legal and economic ramifications. Despite its tragic past thalidomide emerged several decades later as a novel and highly effective agent in the treatment of various inflammatory and malignant diseases. In 2006 thalidomide completed its remarkable renaissance becoming the first new agent in over a decade to gain approval for the treatment of plasma cell myeloma. The catastrophic collapse yet subsequent revival of thalidomide provides important lessons in drug development. Never entirely abandoned by the medical community, thalidomide resurfaced as an important drug once the mechanisms of action were further studied and better understood. Ongoing research and development of related drugs such as lenalidomide now represent a class of irreplaceable drugs in hematological malignancies. Further, the tragedies associated with this agent stimulated the legislation which revamped the FDA regulatory process, expanded patient informed consent procedures and mandated more transparency from drug manufacturers. Finally, we review recent clinical trials summarizing selected medical indications for thalidomide with an emphasis on hematologic malignancies. Herein, we provide a historic perspective regarding the up-and-down development of thalidomide. Using PubMed databases we conducted searches using thalidomide and associated keywords highlighting pharmacology, mechanisms of action, and clinical uses.