Bispecific Antibodies Are Redefining Cancer Therapy

Antibodies floating on blue cell background – 3D illustration

getty

In less than a decade, bispecific antibodies have gone from scientific curiosity to frontline cancer therapeutics. These engineered proteins, capable of binding to two or more targets simultaneously, are reshaping immunotherapy. They are also redrawing the competitive landscape of biopharma itself. With more than 2,000 clinical trials in oncology underway and U.S. cancer drug spending projected to hit $440 billion by 2029, the race is on to harness these molecules.

Five years ago, only a handful of patients had access to bispecific antibody therapies. Today, these drugs are rewriting treatment standards across some of the most challenging cancers. By directly bridging immune cells to tumors or blocking multiple cancer pathways simultaneously, bispecifics have delivered response rates once thought impossible in relapsed myeloma, refractory lymphoma, and even small-cell lung cancer. For patients and physicians, the pace of approval feels less like incremental progress and more like a therapeutic revolution.

What Makes These Antibodies Different

At their core, bispecific antibodies function through dual engagement: one arm binds to a tumor target while the other recruits or redirects immune activity. The most widely used versions are T-cell engagers. The direct tethering transforms resting T cells into potent killers at the tumor site. This is only one mechanism. Other bispecific designs block two growth signaling pathways at once, trap ligands before they can reach receptors, or recruit natural killer cells in addition to T cells.

Multiple myeloma has been a proving ground for these therapies. Drugs like Teclistamab, Talquetamab, and Elranatamab have already earned their place in practice. In July 2025, Linvoseltamab joined the class with results that underscore just how powerful these agents can be. In a trial, patients who had failed four or more lines of treatment—people for whom options had essentially run out—achieved overall response rates above 70%, with nearly half entering complete remission.

The story is equally compelling in lymphomas and leukemia, where the very first bispecific antibody—Blinatumomab, approved back in 2014—set the stage. It has since been joined by Mosunetuzumab, Epcoritamab, and Glofitamab, all of which mobilize T cells against malignant B cells. These drugs have not only extended survival for patients with relapsed disease but have also validated bispecific antibodies as a durable therapeutic class rather than a niche experiment.

Emerging Multispecific Therapies

Cancer has always thrived by exploiting complexity. It’s notorious for evading drugs, resisting monotherapies and rerouting its own biology. The newest wave of multispecific antibodies aims to turn that complexity against the tumor itself. By simultaneously hitting three or more targets, these agents promise not only deeper responses but potentially longer remissions in some of the hardest-to-treat cancers.

If monoclonal antibodies defined the past 25 years, and CAR-T cells the last decade, multispecific antibodies may well shape the next frontier of oncology. These next-generation molecules effectively integrate combination therapy into a single drug, attacking cancer from multiple angles simultaneously. The aim is not incremental improvement, but to stay ahead of the tumor’s notorious ability to adapt and resist.

Researchers are also pursuing tumor-activated designs, sometimes referred to as “prodrug” bispecifics. These remain inert until they encounter enzymes or conditions unique to the tumor microenvironment, triggering activity only at the disease site. The goal is to maintain clinical potency while minimizing systemic risks such as cytokine release syndrome, a common immune-related toxicity.

Together, these innovations reflect a strategic push beyond dual engagement to multispecific control. By targeting three or more pathways or coupling recognition with direct drug delivery, it may be possible to outmaneuver tumor heterogeneity in ways that no single therapy has ever achieved.

Beyond Cancer: New Frontiers

While oncology has been the proving ground for bispecific antibodies, their potential extends far beyond cancer. In fact, two of the most successful examples to date come from entirely different disease areas—hematology and ophthalmology—demonstrating the platform’s core versatility.

In 2017, the FDA approved Hemlibra (emicizumab), a bispecific designed for patients with hemophilia A. For many patients, especially those who had developed antibodies against traditional replacement therapies, it transformed treatment from requiring frequent intravenous infusions to a more manageable under-the-skin injection. Clinical trials showed a dramatic reduction in bleeding episodes, with some patients achieving bleed-free intervals for the first time in their lives. For families long accustomed to hospital visits and transfusions, the shift represented not just a medical advance, but a profound improvement in quality of life.

A more recent breakthrough came in ophthalmology. In 2022, Vabysmo (faricimab) became the first approved bispecific antibody for eye disease, such as neovascular age-related macular degeneration and diabetic macular edema. By attacking both drivers simultaneously, Vabysmo has been shown to reduce retinal fluid, maintain vision, and in many cases extend the interval between treatments—a significant advantage given the burden of frequent eye injections in these patient populations.

Together, Hemlibra and Vabysmo highlight a central theme: bispecific antibodies are not confined to oncology. The implication is clear: as antibody engineering advances, it is likely only a matter of time before bispecifics are applied to other chronic conditions, such as autoimmune disorders, cardiovascular disease, and even infectious diseases. Just as monoclonal antibodies evolved into a mainstay across medicine, the bispecific era may unfold far beyond its cancer origins, opening entirely new therapeutic landscapes.

The Promise and the Trade-Offs

Bispecific antibodies occupy a unique middle ground between conventional monoclonal antibodies and the highly personalized world of cellular therapies like CAR-T. Unlike CAR-T, which requires extracting and re-engineering a patient’s own immune cells—a process that can take weeks and cost hundreds of thousands of dollars—bispecifics are truly “off-the-shelf.” They are manufactured in bulk, stocked like traditional drugs, and ready for immediate use. This logistical simplicity makes them more scalable. It also ensures patients can start treatment without delay, a critical advantage in aggressive diseases such as multiple myeloma or small-cell lung cancer.

Still, this power comes with challenges. The most notable is toxicity management. Because bispecifics ignite immune activity, they can trigger cytokine release syndrome—a systemic inflammatory reaction characterized by fever, low blood pressure and in severe cases, organ dysfunction. Neurological effects such as confusion or seizures, though less common, are also a known risk. The good news is that, with improved monitoring and supportive care, these side effects are typically manageable and much less severe than in many CAR-T protocols.

Another difference is treatment duration. Unlike the “one-and-done” curative intent of CAR-T, bispecifics are generally administered as ongoing infusions or injections. This requires patient adherence to regular dosing schedules but also provides flexibility: doses can be modified or paused based on tolerance, a feature not possible with cell-based therapies.

The Future of Immunotherapy Is Multispecific

As the field matures, oncologists and patients must weigh these benefits and limitations. Bispecifics are faster, more accessible, and generally safer than cellular immunotherapies; however, they may require more sustained treatment and ongoing vigilance. Multispecifics, with their ability to address multiple targets simultaneously, could eventually tip the balance further by improving the durability of response and reducing resistance.

Bispecific and multispecific antibodies are no longer experimental tools—they are an essential arm of modern medicine. Their rapid rise signals a new chapter in cancer treatment. For patients facing diseases once considered untreatable, that chapter cannot come soon enough.