BRAD HANSON, WHO WAS in his late 50s, felt like something was off. He was tired and occasionally dizzy. Blood tests revealed he had anemia, but the cause was unknown. He underwent an endoscopy and saw a rheumatologist—neither found anything concerning. But a 2018 visit with a hematologist-oncologist led to a diagnosis: monoclonal gammopathy of undetermined significance, a disorder in which abnormal proteins build up in the blood and which carries a 1% annual chance of progressing to blood cancer.

A year later, a blood test revealed that things had progressed to a precancerous condition called smoldering myeloma. Plasma cells and proteins in his blood were behaving as if he had active multiple myeloma, a blood cancer, but the condition was not yet causing organ damage, which is indicative of the disease. Agonizingly, the prescription was “watchful waiting,” a standard of care that involves regular monitoring but no medical intervention unless the condition progresses.

“I’m asking my doctors, ‘Can we do something?’” Hanson says, likening the experience to having a ticking time bomb in his body. “I ended up getting depressed. My performance at work suffered, almost lost my job because of it. There’s serious mental anguish.”

In November 2025, the Food and Drug Administration (FDA) approved Darzalex Faspro (daratumumab and hyaluronidase), a monoclonal antibody therapy, to treat high-risk smoldering myeloma. The approval was based on a phase III clinical trial called AQUILA. After a median follow-up of nearly 5.5 years, researchers found that the treatment, administered via subcutaneous injection, lowered the risk of progression from high-risk smoldering myeloma to active multiple myeloma by 50% compared with a group getting active surveillance. Darzalex Faspro is the first drug approved by the FDA for people with smoldering myeloma to lower their risk of progression.

“This is really kind of blazing the trail for future research in this particular space. It’s quite a momentous occasion,” says hematologist and medical oncologist Peter Voorhees, the study’s lead investigator, from Atrium Health Levine Cancer Institute in Charlotte, North Carolina.

And yet, some myeloma researchers and practitioners have raised questions about the findings and how widely treatment should be used. Research has found about 50% of people with high-risk smoldering myeloma who do not receive any treatment will see the condition progress to active multiple myeloma within two years. But most cases are asymptomatic, and some may never see progression. Hearn Jay Cho, a hematologist-oncologist at Mount Sinai Hospital in New York City and chief medical officer at the Multiple Myeloma Research Foundation, says further clarity is needed around the definition of high-risk smoldering myeloma, noting that clinical trials have used varying diagnostic criteria to define the condition.

“Even since AQUILA, the definition of high risk has been refined somewhat further,” Cho says, adding that could potentially shift the results of the study. “It could have either shown a better result, or it may show there was not that big of a difference.”

Cho also isn’t certain that the study’s timeline was long enough to ensure the benefit holds up in the long term.

Weighing Options

Still, Cho has not ruled out prescribing the treatment in his own practice.

“Any decision that is made about an individual’s treatment is a conversation between the patient and me,” Cho says. “It’s great to have hard statistics around certain treatments, but every conversation comes down to: What is the potential for benefit? And what is the potential for risks?”

Voorhees adds that someone treated with Darzalex Faspro may not be eligible to participate in some clinical trials if their condition does eventually progress to active multiple myeloma. Medical guidelines also can rule out the use of a frontline drug like Darzalex Faspro for someone who develops active multiple myeloma if they previously used it for smoldering myeloma. He’s hoping that such protocols are rewritten to avoid disqualifications, but that isn’t a given.

“[There are] all these questions we need to wrap our minds around moving forward. But I think at the end of the day, this is a first step in the right direction,” Voorhees says.

In 2024, Hanson learned his condition had advanced to multiple myeloma, which meant he could take Darzalex. The medication halted the progression of the disease. Hanson also now writes publicly about his experiences, and in May 2025, he testified before the FDA in favor of approving the drug for high-risk smoldering myeloma.

“It’s still up to the local doctor. But it’s another thing in their toolkit for the certain ones you want to treat,” Hanson says.

Kyle Bagenstose is a Philadelphia-based reporter specializing in health and environmental topics.