Multiple myeloma treatment is changing because a new class of drugs — trispecific antibodies — has entered clinical trials with striking results, and several other therapies are rewriting what doctors thought was possible for patients with this blood cancer. ISB 2001, a first-in-class trispecific T cell engager that targets myeloma cells through two surface proteins simultaneously, achieved an overall response rate of 90 percent at effective doses in heavily pretreated patients during its Phase 1 trial. These are patients who had already cycled through a median of four prior treatment regimens, including many who had been exposed to every major drug class available. The FDA has granted ISB 2001 Fast Track Designation, a signal that regulators see genuine urgency in getting this drug to patients who have run out of standard options. But ISB 2001 is only one piece of a broader transformation.
CAR-T therapy with CARVYKTI has now produced five-year survival data showing that a third of patients remained progression-free after a single infusion — no additional myeloma treatment required. Iberdomide, a next-generation drug from Bristol Myers Squibb, is under Priority Review and could become the first approved agent in an entirely new drug class by August 2026. Meanwhile, four bispecific antibodies have already been approved for relapsed or refractory myeloma since 2025, and Mount Sinai researchers now state publicly that a cure for multiple myeloma is possible. For readers of this site who follow brain health and cognitive decline, the connection matters: myeloma and its treatments can affect neurological function, and safer therapies with fewer neurotoxic side effects have real implications for patients managing both cancer and cognitive risk. This article covers the science behind ISB 2001’s dual-targeting approach, the landmark CARVYKTI survival data, the new drug class iberdomide represents, and what all of this means practically for patients and their families navigating treatment decisions.
Table of Contents
- What Is Driving the Shift in Multiple Myeloma Treatment, and How Does a New Drug Achieve 90 Percent Response?
- Five-Year CAR-T Data — What CARVYKTI’s Survival Numbers Actually Mean for Patients
- Iberdomide and the Arrival of an Entirely New Drug Class
- How Patients and Families Should Think About These Treatment Options
- Neurological Considerations That Matter for Brain Health
- The Four Approved Bispecific Antibodies and Where ISB 2001 Fits
- What Comes Next — Can Multiple Myeloma Actually Be Cured?
- Conclusion
- Frequently Asked Questions
What Is Driving the Shift in Multiple Myeloma Treatment, and How Does a New Drug Achieve 90 Percent Response?
The short answer is that researchers have figured out how to attack myeloma cells from multiple angles at once, making it harder for cancer to escape. ISB 2001 is a BCMAxCD38xCD3 trispecific T cell engager, which means it physically redirects the patient’s own T cells to recognize and destroy myeloma cells by grabbing onto two different markers — BCMA and CD38 — on the cancer cell’s surface. Previous bispecific antibodies targeted only one marker, which left an opening for myeloma cells to survive by losing or downregulating that single target. By locking onto two targets simultaneously, ISB 2001 addresses this antigen escape problem directly. In the Phase 1 dose-escalation study, results presented at ASH 2024 and updated at ASCO 2025 showed an overall response rate of 82 percent at doses of 50 micrograms per kilogram or higher across a growing patient cohort, with 30 percent of patients achieving complete or stringent complete responses across seven active dose levels. The initial, smaller cohort hit that 90 percent figure.
These numbers are remarkable given the patient population: all were triple-class exposed, meaning they had already received proteasome inhibitors, immunomodulatory drugs, and anti-CD38 antibodies. Nine of the first 14 patients were penta-exposed, having been through five different drug classes. For context, response rates in heavily pretreated populations have historically hovered around 30 to 60 percent with existing therapies, so an 82 to 90 percent response rate represents a genuine step change. Importantly for readers concerned about neurological safety, ISB 2001 produced no cases of ICANS — immune effector cell-associated neurotoxicity syndrome — in the trial. ICANS is a known risk with some immunotherapies, particularly CAR-T treatments, and can cause confusion, tremors, difficulty speaking, and in severe cases, seizures. Cytokine release syndrome occurred but was manageable. For patients who already face cognitive challenges or who are at elevated risk for neurological complications, this safety profile matters.
Five-Year CAR-T Data — What CARVYKTI’s Survival Numbers Actually Mean for Patients
carVYKTI, the CAR-T therapy developed by Legend Biotech and Johnson & Johnson, has produced the kind of long-term data that shifts how oncologists talk to patients about prognosis. In the CARTITUDE-1 trial, presented at the 2025 ASCO Annual Meeting, 33 percent of patients — 32 out of 97 — remained progression-free for five years or longer after receiving a single infusion of the therapy. No additional myeloma treatment was needed. Median overall survival reached 60.7 months, and at a single center where 12 patients were followed closely, all 12 remained MRD-negative with no detectable disease on annual PET/CT scans across the full five-year period. These patients were not early-stage or newly diagnosed. They had received a median of 6.5 prior lines of therapy, with some having been through as many as 14 different treatment regimens. Ninety percent were triple-class refractory, meaning their cancer had stopped responding to the three major drug classes.
CARVYKTI is now the first and only CAR-T therapy in multiple myeloma to demonstrate an overall survival benefit compared to standard of care, and over 6,500 patients have been treated with it globally. However, CAR-T therapy is not without significant limitations. It requires a complex manufacturing process — a patient’s T cells must be extracted, genetically modified, expanded in a laboratory, and then infused back — which can take weeks. During that waiting period, patients with aggressive disease may deteriorate. Access remains uneven, with manufacturing slots limited and specialized treatment centers concentrated in urban areas. ICANS is a known risk with CAR-T therapies generally, though CARVYKTI’s rate has been lower than some competitors. And for patients with existing cognitive vulnerabilities — whether from age, prior treatments, or early-stage neurodegenerative conditions — the neurological monitoring required during and after infusion is intensive. The five-year data is genuinely exciting, but it applies to a carefully selected patient population under close medical supervision.
Iberdomide and the Arrival of an Entirely New Drug Class
Not all progress in myeloma treatment involves engineered cells or complex immunotherapies. Iberdomide, developed by Bristol Myers Squibb, represents something more quietly revolutionary: the potential first approval of a CELMoD agent, or cereblon E3 ligase modulator. This is a next-generation successor to lenalidomide and pomalidomide, two immunomodulatory drugs that have been pillars of myeloma treatment for years but to which many patients eventually develop resistance. The FDA accepted Bristol Myers Squibb’s new Drug Application in February 2026 for iberdomide in combination with daratumumab and dexamethasone for relapsed or refractory multiple myeloma. The agency granted both Priority Review and Breakthrough Therapy Designation, with a target action date of August 17, 2026.
These designations were based on the Phase 3 EXCALIBER-RRMM study, which randomized roughly 664 patients and showed that the iberdomide combination produced a statistically significant improvement in MRD negativity rates compared to the standard combination of daratumumab, bortezomib, and dexamethasone. What makes iberdomide significant beyond its trial results is what it means for the treatment pipeline. If approved, it opens a new mechanism of action — modifying the cereblon E3 ligase pathway with greater potency than existing drugs in the class. For patients whose myeloma has become refractory to lenalidomide, which is common after extended use, iberdomide could offer a way forward using oral medication rather than infusion-based immunotherapy. It represents the kind of incremental-but-critical advance that extends survival for the broad population of myeloma patients, not just those who qualify for cutting-edge cell therapies.
How Patients and Families Should Think About These Treatment Options
The expanding treatment landscape creates a genuine paradox for patients: more options, but also more complex decisions. The choice between a bispecific antibody like ISB 2001, CAR-T therapy with CARVYKTI, a new oral agent like iberdomide, or one of the four already-approved bispecific antibodies — teclistamab, elranatamab, linvoseltamab, and talquetamab — depends on disease stage, prior treatment history, physical fitness, access to specialized centers, and personal priorities. For newly diagnosed patients, the picture is brighter than it has ever been. First-line treatment response rates now exceed 90 percent with modern combination regimens, and Stage 1 patients are expected to survive more than 10 years with current therapies. The FDA’s approval of quad therapy — daratumumab added to bortezomib, lenalidomide, and dexamethasone — for newly diagnosed patients who are not receiving stem cell transplant gives frontline oncologists a potent starting combination.
The goal in early treatment is depth of response: driving the disease as deep into remission as possible to extend the time before relapse. For patients in later lines of therapy, the tradeoffs are sharper. CAR-T offers the possibility of durable, treatment-free remission — but requires manufacturing time, specialized centers, and carries risks including ICANS. Bispecific antibodies like ISB 2001 or the already-approved options offer high response rates with more immediate availability and, in the case of ISB 2001, a reassuring neurological safety profile. Iberdomide, if approved, provides an oral option that can be combined with existing drugs and administered without the infrastructure that cell therapy demands. There is no single best answer; the best treatment is the one matched to the specific patient’s disease biology, treatment history, and life circumstances.
Neurological Considerations That Matter for Brain Health
For readers of this site, the intersection of myeloma treatment and brain health deserves specific attention. Multiple myeloma itself can cause neurological complications — peripheral neuropathy is common, and the disease can occasionally involve the central nervous system directly. Several standard myeloma treatments, particularly bortezomib and thalidomide, are known to cause or worsen peripheral neuropathy. Prolonged chemotherapy regimens can contribute to cognitive changes sometimes described as chemo brain, which can overlap with or be mistaken for early signs of age-related cognitive decline or dementia. The newer immunotherapies bring different neurological profiles.
ICANS, the neurotoxicity syndrome associated with some CAR-T and bispecific antibody treatments, can range from mild confusion and word-finding difficulty to severe encephalopathy requiring ICU-level care. The fact that ISB 2001 has shown no ICANS cases in its Phase 1 trial is notable, though the data is early and from a relatively small cohort. Talquetamab, one of the approved bispecific antibodies, targets GPRC5D rather than BCMA and has its own distinct side effect profile including taste changes and skin effects, but its neurological risk profile differs from BCMA-targeting agents. Patients with pre-existing cognitive concerns or those caring for someone with both myeloma and a neurodegenerative condition should raise these issues explicitly with their oncology team. Treatment selection should account for baseline neurological function, and cognitive monitoring during immunotherapy is warranted regardless of the specific agent chosen. This is not a reason to avoid effective treatment — the data clearly shows these therapies save lives — but it is a reason to ensure the care team is aware of and actively managing the full picture.
The Four Approved Bispecific Antibodies and Where ISB 2001 Fits
As of 2025, four bispecific antibodies have been approved for relapsed or refractory multiple myeloma: teclistamab, elranatamab, and linvoseltamab (all targeting BCMA and CD3) and talquetamab (targeting GPRC5D and CD3). Each has demonstrated meaningful response rates in patients who have exhausted other options, and together they represent the fastest expansion of a single drug class in myeloma history. ISB 2001 differs from these four because it is trispecific — engaging two tumor targets rather than one.
This dual-targeting approach is designed to reduce the risk of relapse through antigen escape, a problem observed with single-target bispecifics where myeloma cells can downregulate BCMA expression and evade detection. Whether this theoretical advantage translates into longer real-world remissions will require Phase 2 and 3 data, which is the next step in ISB 2001’s development path. For now, the early-phase response rates and clean neurological safety signal are promising enough that the FDA saw fit to accelerate its review.
What Comes Next — Can Multiple Myeloma Actually Be Cured?
Mount Sinai researchers now state that a cure for multiple myeloma is possible, pointing to CAR-T and bispecific antibody strategies as the tools that could get us there. This is a meaningful shift in language from a major academic institution — for decades, myeloma was described as treatable but incurable, and the goal of therapy was always to extend remission, not to eliminate the disease entirely. The five-year CARVYKTI data supports this optimism cautiously.
A third of patients in CARTITUDE-1 have gone five years without progression or additional treatment, and the subset with ongoing MRD negativity and clean PET scans at five years looks, by the available measures, cured. Whether that word can be used formally will require longer follow-up and larger studies, but the trajectory is unmistakable. Combined with first-line response rates above 90 percent, expected survival of more than 10 years for early-stage patients, and multiple new drug classes in the pipeline, the treatment landscape for multiple myeloma has changed more in the past three years than in the previous two decades. For patients and families navigating this disease — particularly those also managing cognitive health — the practical message is that treatment options are more numerous, more effective, and in some cases safer for the brain than what was available even recently.
Conclusion
Multiple myeloma treatment is in the middle of a genuine transformation. ISB 2001’s trispecific approach has demonstrated response rates of 82 to 90 percent in patients who had exhausted most available therapies, with no neurotoxicity signals. CARVYKTI’s five-year data shows that durable, treatment-free remission is achievable after a single infusion. Iberdomide is on track to become the first drug in an entirely new class, with an FDA decision expected by August 2026.
Four bispecific antibodies are already approved and in clinical use. These are not incremental improvements — they represent fundamentally new ways of treating the disease. For patients and caregivers, the practical takeaway is to have an updated conversation with the oncology team about the full range of available and emerging options, particularly if the current treatment is losing effectiveness. For those managing both myeloma and cognitive health concerns, asking specifically about the neurological safety profiles of newer immunotherapies is warranted and important. The science has moved fast, and treatment plans developed even two or three years ago may no longer reflect the best available options.
Frequently Asked Questions
What is a trispecific antibody and how is it different from a bispecific?
A bispecific antibody binds to two targets — typically one on the cancer cell and one on a T cell — to redirect immune attack. A trispecific antibody like ISB 2001 binds to three targets: two on the myeloma cell (BCMA and CD38) and one on the T cell (CD3). This dual tumor-targeting approach is designed to prevent antigen escape, where cancer cells survive by losing a single surface marker.
Is CARVYKTI available to all multiple myeloma patients?
No. CARVYKTI is approved for relapsed or refractory multiple myeloma and requires patients to meet specific eligibility criteria. It is manufactured from the patient’s own T cells, which takes time, and is administered only at certified treatment centers. Access can be limited by manufacturing capacity and geographic availability.
Does CAR-T therapy cause cognitive side effects?
It can. ICANS (immune effector cell-associated neurotoxicity syndrome) is a recognized risk with CAR-T therapies and can cause confusion, difficulty with speech, tremors, or in severe cases, encephalopathy. The severity and incidence vary by product. Patients with pre-existing cognitive concerns should discuss this risk specifically with their care team before treatment.
What is iberdomide and when might it be approved?
Iberdomide is a CELMoD agent — a next-generation successor to drugs like lenalidomide and pomalidomide. It works through the cereblon E3 ligase pathway but with greater potency. The FDA has accepted Bristol Myers Squibb’s application with Priority Review, and the target decision date is August 17, 2026. If approved, it would be the first drug in this new class.
Are newer myeloma treatments safer for the brain than older ones?
The picture is mixed. Some newer immunotherapies, including ISB 2001 in early trials, have shown no neurotoxicity signals, which is encouraging. However, CAR-T therapies carry ICANS risk, and some bispecific antibodies can cause neurological side effects. Older drugs like bortezomib and thalidomide are known to cause peripheral neuropathy. Patients should discuss neurological risk profiles for each specific treatment with their oncologist.
Can multiple myeloma be cured now?
Researchers at institutions like Mount Sinai say a cure is now possible, and the five-year CARVYKTI data supports cautious optimism — about a third of patients in one trial have gone five years without disease progression or additional treatment. However, the word “cure” requires longer follow-up to use formally, and these results come from specific patient populations under close supervision.
