Investigators presented results of a phase II trial of a combination of three oral drugs administered to individuals with smoldering multiple myeloma (SMM), an asymptomatic condition that often progresses to full-blown myeloma within a few years.

The results were presented at the 61st American Society of Hematology (ASH) Annual Meeting.

SMM patients have abnormal proteins and cancer cells in their blood and bone marrow but have no symptoms.

The trial included 53 patients with SMM considered to be at high risk for progression because of genetic characteristics of their cancer cells or the percentage of bone marrow infiltration of the cancer cells, said first author Mark Bustoros, MD, from Dana-Farber’s Center for the Prevention of Progression of Blood Cancers (CPOP).

“We wanted to intervene early in these patients to control the disease and delay progression by using a combination of drugs that would be convenient and with minimal side effects and for a specific period of time,” said Irene Ghobrial, MD, Co-Principal Investigator of CPOP and senior author of the study.

Patients were prescribed a two-year regimen of 24 cycles of the three drugs used to treat myeloma: ixazomib, lenalidomide, and dexamethasone.

Because all the drugs were pills, patients – some of whom lived far from Dana-Farber – only needed to return for blood work and to receive their medications just once a month.

The patients ranged in age from 41 to 84, and many were working full-time.

Data collected at a median follow-up period of 14.4 months showed that the overall response rate of patients who completed at least one cycle of treatment was 91.1%, with 14 complete responses or 31.1% (meaning the abnormal proteins had disappeared), nine very good partial responses, or 20%, and 18 partial responses (40%) and four minimal responses (10%).

Thus far, none of the patients in the study have progressed to overt myeloma, Bustoros said.

However, the patients haven’t been followed long enough yet for the study to show whether the treatment has extended their progression-free survival, he added: that will take another two years.

Historically, 50 percent of patients with high-risk smoldering myeloma develop myeloma within two years.

The drug combination was well-tolerated, and no patients had to discontinue the treatment because of adverse effects.

“These are encouraging results,” he said, “and we hope with a longer follow-up time we will see patients having a durable response” after finishing the two-year course of treatment. “That’s the goal,” he said.

Source: Dana-Farber Cancer Institute