Hematologist Sagar Lonial, MD, a multiple myeloma specialist and researcher at Emory University, Atlanta, argued for treatment. Hematologist Angela Dispenzieri, MD, also a myeloma researcher and specialist at the Mayo Clinic in Rochester, Minn., took the opposing side, arguing for watchful waiting.
The two experts based their arguments largely on the same two studies, the only randomized trials to tackle the issue to date. While Dr. Dispenzieri focused on their shortcomings, Dr. Lonial focused on their strengths.
In a poll after the debate, about a third of audience members agreed that watchful waiting is the way to go, but about two-thirds favored a personalized approach to smoldering myeloma treatment based on patient risk.
“I’m taking this as a win,” Dr. Lonial said.
Different interpretations of two trials
The first of the two trials recruited from 2007 to 2010 and was conducted in Spain and Portugal. Fifty-seven high-risk patients were randomized to lenalidomide plus dexamethasone (Len-Dex) for up to 2 years; 62 others were randomized to observation.
At 3 years, 70% of observed patients had progressed to multiple myeloma versus only 20% in the Len-Dex group; 82% of Len-Dex patients were alive at data cut-off in 2015 versus 64% of observation patients.
The second, more recent trial, which was led by Dr. Lonial, randomized 92 intermediate or high-risk smoldering myeloma patients to lenalidomide alone for a median of 2 years and 90 others to observation. Three-year progression-free survival (PFS) was 91% in the treatment arm versus 66% with observation. Overall survival data have not yet been reported.
Dr. Dispenzieri acknowledged that the results from Spain and Portugal are impressive. “Treating with Len-Dex gives you a far superior freedom from progression. ... Overall survival was better too.” Results for Len-Dex were “fantastic,” she said.
However, the trial was done before myeloma-defining event criteria existed, so it’s very likely that the treatment arm in the Spanish study included actual myeloma cases, she said.
About 46% of treated patients in Dr. Lonial’s study met the current definition for high risk for progression based on the 2-20-20 rule, which Dr. Dispenzieri helped develop. Although there was an improvement in PFS in the high-risk group, there was no significant improvement for intermediate- and low-risk subjects. Also, more than 80% of observed patients hadn’t progressed by 2 years, and overall survival data are missing.
Meanwhile, treated patients in both trials had more adverse events, including secondary malignancies, and there’s the possibility that early treatment may make patients resistant to treatment later on when they progress to multiple myeloma, although that didn’t seem to happen in the Spanish trial.
“Of course, we want to prevent morbidity, of course we would love to cure the disease,” but “should we treat high-risk smoldering myeloma patients based on overall survival data from a trial of” just 119 “patients that may have been contaminated with actual myeloma” cases? Is it ethical to treat low- and intermediate-risk patients who have only a 50% chance of developing myeloma after 10 years?”
Her answer to both questions was “no and no. ... There’s just a lot of work to be done” to better understand the condition and when and how to intervene. In the meantime, “don’t treat smoldering melanoma patients” outside of a trial, she said.
“First, do no harm,” Dr. Dispenzieri cautioned in her final slide.
Dr. Lonial said he agreed with many of Dr. Dispenzieri’s points, but disagreed with her conclusion not to treat.
“Everybody can always be critical of randomized trials, but at the end of the day, we now have two randomized phase 3 trials comparing early intervention with no intervention demonstrating a significant delay in developing myeloma. I think it’s time to end the ‘we need more data; we need more trials.’ It’s time for us to take a stand.”
He argued for 2 years of lenalidomide for patients who meet the 2-20-20 high-risk definition, based on the median time people were treated in his trial.
He said he discusses the option “with every smoldering patient [who] walks in to see me” if they aren’t eligible for a trial.
Dr. Lonial mentioned his team is currently pulling together longer-term survival data for their trial.