SUMMARY: Multiple Myeloma is a clonal disorder of plasma cells in the bone marrow and the American Cancer Society estimates that in the United States, 30,770 new cases will be diagnosed in 2018 and 12,770 patients are expected to die of the disease. Multiple Myeloma in 2018 remains an incurable disease. The therapeutic goal therefore is to improve Overall Survival (OS) in the relapsed setting.
KYPROLIS® (Carfilzomib) is a second generation selective, epoxyketone proteasome inhibitor and unlike VELCADE® (Bortezomib), proteasome inhibition with KYPROLIS® is irreversible. Most of the recent phase III trials in Relapsed or Refractory Myeloma have used Progression Free Survival (PFS) as the Primary end point, with the exception of the phase III trial ENDEAVOR trial in which patients treated with KYPROLIS® and Dexamethasone achieved a statistically significant 7.6-month improvement in median Overall Survival (OS) compared to those patients treated with VELCADE® and Dexamethasone (HR=0.79; P=0.01). REVLIMID® (Lenalidomide) given along with weekly Dexamethasone, was associated with significantly improved Progression Free Survival (PFS) when administered until disease progression, in patients with newly diagnosed Multiple Myeloma. The combination of REVLIMID® and weekly Dexamethasone is considered a reference regimen for both newly diagnosed and relapsed Multiple Myeloma. VELCADE® in combination with REVLIMID® and Dexamethasone showed an overall response rate of 64% and a median PFS of 9.5 months in patients with Relapsed or Refractory Multiple Myeloma.
Based on this background, a randomized, open label, multicenter, phase III study (ASPIRE) was conducted, in which the safety and efficacy of a combination of KYPROLIS® (Carfilzomib), REVLIMID® and weekly Dexamethasone (KRd) was compared with a combination of REVLIMID® and weekly Dexamethasone (Rd), in patients with Relapsed or Refractory Multiple Myeloma. Seven hundred and ninety two (N=792) patients were randomly assigned in a 1:1 ratio to KRd (N=396) and Rd (N=396). Eligible patients included those with Multiple Myeloma who had received one to three prior treatments which included VELCADE® or REVLIMID® and Dexamethasone combination, provided that they did not have disease progression during treatment with these agents. The 28 day treatment cycle consisted of KYPROLIS® IV given on days 1, 2, 8, 9, 15, and 16 (starting dose, 20 mg/m2 on days 1 and 2 of cycle 1 with a target dose of 27 mg/m2 thereafter) during cycles 1 through 12 and on days 1, 2, 15, and 16 during cycles 13 through 18, following which KYPROLIS® was discontinued. REVLIMID® 25 mg PO was given on days 1 through 21 and Dexamethasone 40 mg PO was administered on days 1, 8, 15, and 22. Patients in both treatment groups received only REVLIMID® and Dexamethasone after cycle 18 until disease progression. Antiviral and antithrombotic prophylaxis was administered to patients in both treatment groups. The Primary end point was Progression Free Survival (PFS) and secondary end points included Overall Survival (OS), the rate of overall response (partial response or better), response duration, health-related quality of life, and safety.
The study met its Primary endpoint at the time of the pre-specified interim analysis with a significant improvement in the median PFS for those patients in the KRd group compared to the Rd (26.3 months versus 17.6 months; HR=0.69; P=0.0001). This benefit in the PFS was demonstrated across all predefined subgroups. The overall response rates (partial response or better) were 87.1% and 66.7% in the KYPROLIS® and control groups, respectively (P<0.001). Further, patients in the KYPROLIS® group reported superior health-related quality of life.
The authors in this prespecified analysis reported the final Overall Survival (OS) data and updated safety results. The median follow up was 67.1 months. The median OS was 48.3 months in the KRd group and 40.4 months in the Rd group (HR=0.79; P=0.0045). This represented a 7.9 month prolongation of OS and 21% decrease in the risk of death with KRd. Among patients who had received one prior line of therapy, KRd improved median OS by 11.4 months and among those who had received 2 or more prior lines of therapy, KRd improved median OS by 6.5 months, compared to Rd. Among patients who had received one prior line of VELCADE® based therapy, the median OS was improved by 12 months with KRd versus Rd, with a 18% reduction in the risk of death, and among patients with prior transplantation at first relapse, the median OS was improved by 18.6 months with KRd versus Rd, with a 29% reduction in the risk of death. The OS benefit with KRd was noted across all age, Creatinine Clearance (CrCL) and ECOG PS subgroups, including those 75 years or older, patients with impaired renal function (CrCL 30 to less than 60 mL/min), and patients with decreased Performance Status (ECOG PS, 2). The median time to next treatment from time of randomization was 39.0 months for patients who received KRd and 24.4 months for those who received Rd (HR=0.65; P<0.001).
An updated median PFS with longer follow up (median , 48.4 months) was 26.1 months in the KRd group versus 16.6 months in the Rd group (HR=0.66; P<0.001). Grade 3 or higher adverse events were reported in 87% and 83.3% of patients in the KRd and Rd groups, respectively.
It was concluded that treatment with KRd resulted in a statistically significant and clinically meaningful reduction in the risk of death, compared to Rd, among patients with Relapsed or Refractory Myeloma. This analysis supports the early use of KYPROLIS® at first relapse, regardless of prior treatment with VELCADE® or transplantation. Because each subsequent line of therapy can result in shorter response duration and increased treatment resistance, the authors suggested that early treatment with an effective regimen is important to maximize Overall Survival and KRd regimen should be considered a preferred treatment option in Relapsed or Refractory Multiple Myeloma. Improvement in Overall Survival With Carfilzomib, Lenalidomide, and Dexamethasone in Patients With Relapsed or Refractory Multiple Myeloma. Siegel DS, Dimopoulos MA, Ludwig H, et al. J Clin Oncol. 2018;36:728-734
