has received research support from Bristol Myers Squibb and Novartis, and has consulted for Array Biopharma, Celgene, GlaxoSmithKline, Bristol Myers Squibb, Seattle Genetics, Janssen, Takeda, Oncopeptides, and Kite Pharma; S.H. benefit of 3 months. Certain adverse events (AE) were Ned 19 more frequent in Arm 2, including fatigue, thrombocytopenia and peripheral neuropathy, but there was no significant difference in cardiopulmonary AEs. Conclusions This randomized trial did not support a benefit of fixed-duration, twice-weekly 56 mg/m2 dosing of carfilzomib over the 27 mg/m2 dose for the treatment of relapsed and/or refractory MM. However, treatment to progression in earlier patient populations with high-dose carfilzomib using different schedules should still be considered as part of the standard of care. Introduction Multiple myeloma (MM) is the second most common hematological malignancy, with more than 30,000 patients diagnosed in the United States (U.S.) Ned 19 every year.1 There have been tremendous improvements in outcomes of MM patients, with an estimated 5-12 months overall survival (OS) of 50.7%, as compared to only 34.6% less than two decades ago,2,3 mainly due to a better understanding Ned 19 of disease biology and the development of novel therapeutic brokers. Proteasome inhibitors represent one such category of anti-MM therapeutic brokers.4 The ubiquitin proteasome pathway is a central component of the cellular protein-degradation machinery with essential functions in homeostasis, which include preventing the accumulation of misfolded or deleterious proteins.5 Inhibition of this pathway causes disruption of this homeostasis and intracellular accumulation of protein-degradation byproducts, leading to cell death. The first proteasome inhibitor, bortezomib, was approved by the FDA for treatment of patients with MM in 2003.6 Since then carfilzomib, and most recently ixazomib, have gained FDA approval.7 The utilization of these agents has evolved from single-agent to combination regimens, from later lines of therapy to earlier in the treatment paradigm of MM patients, and with changes in the dosage and mode of administration to deliver them in the safest and most efficacious manner.4,8 Amongst these changes, the utilization of carfilzomib has evolved substantially over time. Carfilzomib was initially approved as a single-agent for the treatment of relapsed and/or refractory MM (RRMM) in patients who had received at least two prior lines of therapy, including a proteasome inhibitor and an immunomodulatory agent (IMiD).9 The initially approved dose of carfilzomib was Rabbit Polyclonal to SERPING1 20 mg/m2 intravenously (IV) administered as a single-agent on days 1, 2, 8, 9, 15 and 16 every 28 days for the first cycle, followed by 27 mg/m2 on the same schedule starting cycle 2 onwards for a total of 12 cycles. Since then, several clinical trials have led to significant changes in its usage, including escalating to 27 mg/m2 starting on day 8 of cycle 1, increasing the subsequent doses to 36 mg/m2 or 56 mg/m2 twice-weekly, using it in combination with other agents, and once-weekly at 70mg/m2.10C14 All these data resulted in changes to the FDA label for carfilzomib.15 The current FDA-approved clinical indications for carfilzomib are summarized in Table 1. Table 1. Current FDA-approved Variations of Carfilzomib in Relapsed and/or Refractory Multiple Myeloma thead th align=”left” valign=”top” rowspan=”1″ colspan=”1″ Regimen /th th align=”center” valign=”top” rowspan=”1″ colspan=”1″ Dose /th th align=”center” valign=”top” rowspan=”1″ colspan=”1″ Schedule /th /thead Monotherapy20/27 mg/m2Twice-weeklyCarfilzomib, Lenalidomide, Dexamethasone20/27 mg/m2Twice-weeklyMonotherapy20/56 mg/m2Twice-weeklyCarfilzomib, Dexamethasone20/56 mg/m2Twice-weeklyCarfilzomib, Dexamethasone20/70 mg/m2Once-weekly Open in a separate window Despite several clinical trials evaluating various carfilzomib-containing regimens in differing doses, schedules and clinical settings, no study has previously compared different doses of this agent on the same schedule in a randomized trial to understand their mutual safety and efficacy. The recently published randomized A.R.R.O.W. trial did compare two doses of carfilzomib, but they were administered in differing schedules, once-weekly (70 mg/m2) versus twice-weekly (27 mg/m2).13 SWOG undertook an intergroup randomized phase 2 clinical trial, S1304, to compare the safety and efficacy of low-dose (27 mg/m2) versus high-dose (56 mg/m2) carfilzomib with dexamethasone administered twice-weekly for RRMM (“type”:”clinical-trial”,”attrs”:”text”:”NCT01903811″,”term_id”:”NCT01903811″NCT01903811). We present here the primary results from this clinical trial. Patients and Methods This national, multicenter, open-label phase 2 randomized clinical trial was approved by the Cancer Therapy Evaluation Program (CTEP), relevant institutional review boards, and was conducted according to the Declaration of Helsinki. All patients provided written informed consent. Statistical analyses were conducted at the SWOG Statistics and Data Management Center Ned 19 in Seattle, WA. Study Design This randomized phase 2 trial compared low-dose carfilzomib plus dexamethasone (Arm 1) with high-dose carfilzomib plus dexamethasone (Arm 2) in RRMM. Patients who had disease progression any time between cycle 3 and 12 on arm 1 could crossover to high-dose.