Multiple Myeloma Not Having Achieved Remission: What’s Next?

When multiple myeloma does not respond to initial treatment or fails to reach at least a partial response, doctors call it “primary refractory” disease, and it changes the conversation about what comes next. A study of over 800 patients treated since 2006 found that those with primary refractory myeloma had a median overall survival of about 3.6 years, compared with roughly 7.6 years for patients who did respond to their first treatment.¹ That gap is significant, but it does not mean options are exhausted. The treatment landscape for myeloma that has not achieved remission has expanded dramatically in recent years, with new drug classes, immunotherapies, and biomarker-guided approaches offering paths that did not exist a decade ago.

What “Not Achieving Remission” Means in Practice

Doctors evaluate myeloma response using a graded scale. A complete response means no detectable myeloma protein in the blood or urine and fewer than five percent plasma cells in the bone marrow. A partial response means at least a fifty percent drop in myeloma protein. When treatment fails to produce even a partial response, the disease is considered primary refractory. This is different from relapsed myeloma, where someone initially responded but later saw the disease return. The distinction matters because primary refractory disease tends to behave more aggressively and often requires a fundamentally different therapeutic strategy rather than simply repeating a similar regimen.

The survival gap between responders and non-responders persisted even when researchers looked only at patients whose initial treatment included a newer drug, with median survival still at 3.6 years for the refractory group versus 7.9 years for responders.¹ These numbers set the baseline, but they predate several of the newest treatments and should be understood as the starting point for the conversation, not the final word.

Why Some Myelomas Resist Treatment

Myeloma is not one disease. At the genetic level, each person’s myeloma carries a unique collection of chromosomal changes and mutations. Early changes, such as certain chromosomal gains or rearrangements involving the immunoglobulin heavy chain gene, establish a founding population of cancer cells. Over time, that population diversifies. Some cells acquire additional mutations or changes in how their genes are regulated, and this creates an internal diversity within the tumor that researchers call clonal heterogeneity.² When treatment kills the majority of cancer cells, the resistant minority can survive and expand. This is why certain high-risk genetic features at diagnosis, such as specific chromosomal deletions or translocations, predict a harder time achieving remission.

Understanding the genetic makeup of a person’s myeloma is increasingly important for choosing the next treatment. Comprehensive genetic testing at diagnosis and again at the time of treatment failure can reveal whether the disease has shifted in ways that open new therapeutic options or explain why a particular drug class did not work.

Switching to a Different Drug Class

If the initial regimen included a proteasome inhibitor like bortezomib and failed, the first consideration is often switching to a different mechanism of action entirely, or trying a newer drug within the same family that can overcome the specific resistance. Carfilzomib, a second-generation proteasome inhibitor, has documented activity in patients whose disease was refractory to bortezomib. It works through the same general pathway but binds its target differently, which can partially overcome the resistance that developed against the older drug. Responses tend to occur quickly and last for a meaningful period in most patients who do respond.³

For patients whose myeloma has stopped responding to immunomodulatory drugs like lenalidomide or pomalidomide, a newer class called CELMoDs is emerging. Mezigdomide works through a similar protein target but with greater potency, including in laboratory models of myeloma resistant to the older drugs. In a clinical trial of patients with heavily pretreated disease, mezigdomide combined with dexamethasone produced an overall response in about forty percent of patients, with a median time before the disease progressed again of roughly four and a half months.⁴ Those numbers may sound modest, but in a population where every prior drug class has already failed, any meaningful response represents real time gained.

Selinexor is another option that works through an entirely different mechanism: it blocks a protein called exportin 1 that cancer cells use to shuttle tumor-suppressing proteins out of the nucleus, effectively trapping those proteins where they can do their job. Selinexor-based combinations have been approved for patients who have relapsed after at least one prior therapy, and the drug has shown consistent activity across particularly difficult subgroups, including patients with triple-class refractory disease, kidney dysfunction, and high-risk genetic features.⁵ That breadth of activity across resistant populations is unusual and makes selinexor a particularly relevant choice when the standard classes have all been tried.⁶

Immunotherapy Options

The biggest shift in myeloma treatment over the past several years has been the arrival of therapies that harness the immune system to attack myeloma cells directly. These come in three main forms, and they have been especially transformative for patients who have not responded to other approaches.

CAR T-Cell Therapy

CAR T-cell therapy involves removing a patient’s own immune cells, engineering them in a laboratory to recognize a protein on myeloma cells called BCMA, and infusing them back. In a landmark trial of the product idecabtagene vicleucel (ide-cel, originally called bb2121), the objective response rate was eighty-five percent among heavily pretreated patients, with about forty-five percent achieving a complete response. Every evaluable patient who reached at least a partial response tested negative for minimal residual disease, meaning no detectable myeloma at an extremely sensitive threshold. The median time before disease progression was nearly twelve months.⁷ These are striking results in a population where most conventional drugs had already stopped working.

CAR T comes with significant practical hurdles, though. Manufacturing takes several weeks, during which your disease may progress. The treatment requires specialized centers, a hospital stay, and close monitoring for side effects. Access is also uneven: data show that among myeloma patients receiving CAR T on clinical trials, only about one percent were African American, about five percent were Hispanic, and the vast majority came from higher-income neighborhoods.⁸ These disparities are a real barrier that researchers and advocacy groups are working to address.

Bispecific Antibodies

Bispecific antibodies are “off-the-shelf” immunotherapies, meaning they do not require the weeks of custom manufacturing that CAR T does. They work by physically linking a T cell to a myeloma cell, forcing the immune cell to attack the cancer. Teclistamab targets BCMA, while talquetamab targets a different protein called GPRC5D. In a phase 1 study, talquetamab produced responses in about sixty-four to seventy percent of heavily pretreated patients who had gone through a median of six prior lines of therapy.⁹ Both drugs are approved for patients with triple-class refractory myeloma.¹⁰

One advantage of having both BCMA-targeting and GPRC5D-targeting bispecifics is sequencing: if disease progresses after a BCMA-directed therapy, a GPRC5D-directed therapy attacks through a completely different surface protein, sidestepping some forms of resistance. Researchers are also testing combinations of the two bispecifics together to hit myeloma from two angles simultaneously.

Why BCMA Is Such an Important Target

A systematic review of patients whose myeloma was refractory to daratumumab, the widely used anti-CD38 antibody, found that the treatment options producing the highest response rates and longest survival almost all shared one feature: they targeted BCMA. Drugs aimed at this protein, whether delivered as CAR T cells, bispecific antibodies, or antibody-drug conjugates, have shown high activity even in daratumumab-refractory disease.¹¹ The caveat is that many of these patients had never been exposed to a BCMA-directed drug before, so the full picture of how BCMA-targeting therapies perform after prior BCMA exposure is still developing.

Can a Second Stem Cell Transplant Help?

For patients who responded to their first autologous stem cell transplant and maintained that response for a meaningful period, a second transplant remains a viable option at relapse. A French study of 267 patients who received a second transplant found low early mortality (about one percent), a deep response rate of seventy-eight percent, and a median overall survival of over eight years from the time of the second transplant.¹² Maintenance therapy after the second transplant was associated with longer disease control and survival, particularly for patients who achieved a deep response.

A separate analysis confirmed that second transplants can be effective even in older patients or those with kidney problems, with reduced-dose conditioning producing similar outcomes to full-dose conditioning.¹³ The key question is selection: second transplant works best when the first transplant produced a response that lasted at least a couple of years, the patient is fit enough for the procedure, and stored stem cells are available. For someone whose disease was primary refractory and never responded to initial therapy at all, a transplant is generally not the recommended next step.

Biomarker-Guided Therapy

One of the clearest examples of precision medicine in myeloma involves the translocation t(11;14), a genetic rearrangement present in roughly fifteen to twenty percent of patients. This abnormality causes myeloma cells to depend heavily on a protein called BCL-2 for survival, making them vulnerable to venetoclax, a drug originally developed for a type of leukemia. In a study of patients with t(11;14)-positive relapsed or refractory myeloma, venetoclax combined with dexamethasone produced an overall response rate of about sixty percent, with a median time to disease progression of over twelve months.¹⁴ A real-world study from Hungarian centers reported even higher response rates, with ninety-four percent of t(11;14) patients responding in the relapsed or refractory setting.¹⁵

The point is straightforward: if you have not had your myeloma’s genetics checked recently, or if testing was done only at diagnosis and never repeated, it is worth asking your oncologist about updated testing. The specific genetic features of your disease can open doors to treatments that would not be considered otherwise.

Tracking Response with MRD Testing

Minimal residual disease (MRD) testing looks for myeloma cells at a level far below what standard blood and urine tests can detect, typically identifying one cancer cell among a hundred thousand normal cells or more. The International Myeloma Working Group established criteria in 2014 defining MRD-negative status using either next-generation sequencing or advanced flow cytometry on bone marrow samples.¹⁶

Achieving MRD-negative status is a strong predictor of longer remission and survival. For someone who has not reached remission by standard measures, MRD testing might seem irrelevant, but it actually plays a growing role in treatment decisions at every stage. Ongoing clinical trials are testing whether treatment should be intensified when MRD remains positive, whether maintenance therapy can be stopped when MRD stays negative for a sustained period, and whether a switch from MRD-negative to MRD-positive should trigger an early change in treatment.¹⁷ For patients who have not achieved remission, the concept of MRD-guided escalation is especially relevant: rather than waiting for obvious signs of progression, doctors may use MRD results to decide more quickly that a switch to a more aggressive approach is warranted.

Managing Side Effects of Newer Therapies

The immunotherapies that are reshaping myeloma treatment come with a distinct side-effect profile that looks different from traditional chemotherapy. The two most discussed are cytokine release syndrome and a neurological complication called immune effector cell-associated neurotoxicity syndrome. Cytokine release syndrome happens when activated immune cells release a flood of inflammatory signals, causing fever, low blood pressure, and breathing difficulty. It occurs commonly with both CAR T-cell therapy and bispecific antibodies, though doctors have developed effective management strategies including step-up dosing schedules and medications like tocilizumab that block the inflammatory cascade.¹⁸

Infection is another major concern. Both CAR T and bispecific antibodies can cause severe drops in antibody levels, leaving patients vulnerable to bacterial, viral, and fungal infections. Research has linked infection risk specifically to severe immunoglobulin deficiency, and immunoglobulin replacement therapy can help.¹⁹ A study of patients treated with anti-BCMA bispecific antibodies found that preemptive immunoglobulin supplementation reduced all-grade infections by about two-thirds and severe infections by about three-quarters compared with patients who did not receive preemptive supplementation.²⁰ If you are starting a bispecific antibody or recovering from CAR T, asking your care team about prophylactic immunoglobulin infusions is a reasonable conversation to have.

Bone and Kidney Support

Myeloma is not just a blood cancer; it damages bone and kidneys in most patients. About seventy to eighty percent of patients have bone lesions at diagnosis, and roughly sixty percent develop kidney dysfunction at some point during the disease.²¹ These complications do not go away when the myeloma is not responding to treatment. If anything, they can worsen, making supportive care critical.

For bone protection, bisphosphonates like zoledronic acid and pamidronate remain the standard. They reduce fractures, bone pain, and dangerous calcium spikes. However, they cannot be used at full doses in patients with severe kidney damage.²² For those patients, denosumab offers an alternative because it does not need dose adjustment for kidney function.²¹ Local radiation therapy can quickly relieve painful bone lesions, and procedures like vertebroplasty or kyphoplasty can stabilize and restore height to collapsed vertebrae.²³

For kidney dysfunction caused by myeloma-related proteins, the priority is getting the myeloma under control as quickly as possible using an effective regimen. Bortezomib-based combinations are the standard of care when kidney impairment is present, both because bortezomib works against the underlying disease and because it does not require dose reduction for kidney problems.²²

Targets Beyond BCMA and GPRC5D

With more patients now being exposed to BCMA-directed therapies, the field is actively pursuing additional targets for when those drugs stop working. One of the most advanced is FcRH5, targeted by the bispecific antibody cevostamab. In a large phase 1 trial involving 324 heavily pretreated patients, most of whom had triple-class refractory disease and nearly half of whom had already received a prior BCMA-targeted therapy, cevostamab produced an overall response rate of about forty-two percent with a median duration of response of over eleven months.²⁴ Interestingly, when data were looked at specifically in patients who had previously received a BCMA-directed bispecific antibody, the response rate was lower, around ten percent, though stable disease was observed in nearly half of those patients.²⁵

Researchers are also developing trispecific antibodies that engage two targets on the myeloma cell simultaneously while redirecting T cells, and exploring other surface proteins as potential therapeutic targets.²⁶ The overarching pattern is clear: each new target and mechanism provides another step in the treatment sequence. The challenge is figuring out the optimal order, and a growing body of clinical trials is designed to answer exactly that.

Making Decisions When the Path Is Uncertain

When myeloma has not achieved remission, treatment decisions become more complex and more personal. A multinational study of patients and healthcare professionals identified several decision points where shared decision-making is considered especially important: choosing among multiple treatment options, weighing new therapies that have limited long-term data, deciding whether to change therapy due to progression or relapse, considering participation in a clinical trial, and, when the time comes, decisions about stopping treatment and focusing on comfort care.²⁷

Clinical trial participation deserves particular attention for patients with refractory disease. For those whose myeloma has not responded to standard drug classes and transplant, trials evaluating agents with entirely new mechanisms of action may offer the best chance at a meaningful response.²⁸ Resources like ClinicalTrials.gov or your treatment center’s clinical trial office can help identify studies that match your specific disease profile. Many of the drugs discussed in this article, including mezigdomide and cevostamab, are available primarily or exclusively through trials for certain indications. Asking about trials is not giving up on standard treatment; it is often how the next standard treatment becomes available.

The landscape for myeloma that has not reached remission is genuinely different from what it was even five years ago. Between new drug classes, immunotherapies targeting multiple different proteins, biomarker-guided strategies, and improved supportive care, the list of realistic next steps is longer and more diverse than at any point in the disease’s history. That does not erase the seriousness of refractory disease, but it does mean the conversation about what comes next has more substance behind it.