Presenter: Joshua Richter, MD, Assistant Professor of Medicine, Icahn School of Medicine at Mount Sinai
Co-Authors: Habte A. Yimer, Texas Oncology/US Oncology Research, Tyler, TX; Stephen J. Noga, Millennium Pharmaceuticals, Cambridge, MA, a wholly owned subsidiary of Takeda; Sudhir Manda, Arizona Oncology/US Oncology Research, Tucson, AZ; Roger M. Lyons, Texas Oncology/US Oncology Research, San Antonio, TX; Kimberly Bogard, Millennium Pharmaceuticals, Cambridge, MA, a wholly owned subsidiary of Takeda; Presley Whidden, Millennium Pharmaceuticals, Cambridge, MA, a wholly owned subsidiary of Takeda; Dasha Cherepanov, Millennium Pharmaceuticals, Cambridge, MA, a wholly owned subsidiary of Takeda; Jack Aiello, Patient Empowerment Network, San Jose, CA; Saulius Girnius, Trihealth Cancer Institute, Cincinnati, OH; Robert M. Rifkin, Rocky Mountain Cancer Centers/US Oncology Research, Denver, CO
Background: Long-term proteasome inhibitor (PI)-based treatment is associated with improved outcomes in multiple myeloma. However, prolonged therapy with parenteral PIs can be challenging. The US MM-6 study (NCT03173092) is investigating in-class transition from parenteral bortezomib-based induction to all-oral ixazomib-lenalidomide-dexamethasone (IRd) in US community patients, with the aim of increasing PI-based treatment duration, while maintaining quality of life and improving outcomes.
Objectives: The primary end point is progression-free survival (PFS); key secondary end points include rate of partial response, very good partial response (VGPR), and complete response (CR) rates, as well as duration of therapy.
Methods: Transplant-ineligible patients or patients with delayed (>24 months) newly diagnosed multiple myeloma and stable disease or better after 3 cycles of bortezomib-based induction are being enrolled to undergo in-class transition and receive IRd (up to 39 28-day cycles or until disease progression or unacceptable toxicity).
Results: At data cutoff, 101 patients had received treatment. The patients’ median age is 73 years; 46% are aged ≥75 years; 16% are black/African American; 10% are Hispanic/Latino; 26% have calculated creatinine clearance <60 mL/min. At the start of IRd therapy, 95% of patients had ≥1 comorbidities, including renal and urinary disorders (38%), cardiac disorders (29%), and peripheral neuropathy (14%). With 52% of the patients continuing therapy and the enrollment is ongoing, the mean duration of therapy from the start of bortezomib-based induction was 12.4 months; mean IRd duration of therapy after in-class transition was 9.2 months. Patients have received IRd for up to 29.4 months to date. The overall response rate (ORR) after bortezomib-based induction was 62% (7% CR, 32% ≥VGPR). After in-class transition, the ORR increased to 71%, and the CR and ≥VGPR rates increased to 29% and 53%, respectively. The 12-month PFS rate was 84% from the start of bortezomib-based induction and 80% from the start of IRd. During IRd treatment to date, 91% of patients have had treatment-emergent adverse events (AEs; 53% grade ≥3). Treatment-emergent AEs led to study-drug modification and discontinuation in 52% and 7% of patients, respectively. Serious treatment-emergent AEs occurred in 37% of the patients. Diarrhea, peripheral neuropathy, nausea, and vomiting occurred in 43% (8% grade 3), 32% (2%), 23% (2%), and 14% (2%) of patients, respectively. Other (≥5%) grade 3 treatment-emergent AEs were pneumonia (7%) and syncope (5%).
Conclusion: Patients in the US MM-6 study reflect the real-world US population with multiple myeloma, including mostly elderly, comorbid, community-based patients with newly diagnosed multiple myeloma. In-class transition to IRd after 3 cycles of bortezomib-based induction resulted in improved response rates and depths of responses, as well as prolonged duration of therapy, and may thereby improve outcomes for real-world patients. In-class transition to an all-oral regimen could also prevent treatment interruptions for patients who are unable to, or prefer not to, travel regularly to a clinic for treatment.