Multiple myeloma is an aggressive form of blood cancer that affects plasma cells in the bone marrow. Although it often starts silently, new treatments targeting GPRC5D are changing the game—especially for patients with relapsed or treatment-resistant myeloma.
What Is Multiple Myeloma?
Multiple myeloma is a type of cancer that begins in plasma cells, which help fight infection. When these cells become malignant, they can crowd out healthy cells, weaken bones, and cause organ damage. Early detection is critical, yet many people only learn they have myeloma after routine blood tests reveal abnormalities.
What Are the Early Signs of Myeloma?
Early-stage myeloma (such as MGUS or smoldering myeloma) may not cause symptoms. However, subtle warning signs include:
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Persistent fatigue
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Frequent infections
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Bone pain, especially in the spine or ribs
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Unexplained weight loss
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Excessive thirst or urination (linked to high calcium levels)
If you experience these symptoms, ask your doctor about screening for multiple myeloma, particularly if you’re over 60 or have a family history of blood cancers.
MGUS and Smoldering Myeloma: The Precursors
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MGUS (Monoclonal Gammopathy of Undetermined Significance): Considered a benign but watchful condition. About 1% of people with MGUS progress to myeloma per year.
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Smoldering Multiple Myeloma (SMM): An intermediate stage with a higher risk of progression—approximately 10% per year for the first five years.
Doctors typically use a “watch-and-wait” strategy for both, monitoring patients with blood and urine tests until progression is confirmed.
The Rise of GPRC5D Antibody Therapy
GPRC5D is a promising new target in multiple myeloma research. Expressed on malignant plasma cells—but not on most normal tissues—GPRC5D is now being targeted by experimental GPRC5D antibody drugs and GPRC5D CAR T-cell therapies.
These therapies work by engineering a patient’s own immune cells (T-cells) to recognize and destroy cells expressing GPRC5D. Early clinical trials have shown powerful responses, even in patients who have failed multiple lines of prior therapy.
One such investigational treatment is Talquetamab, a bispecific antibody targeting both GPRC5D and CD3. Studies suggest it may help patients for whom other options have run out.
CAR T Cell Therapy in Multiple Myeloma
CAR T-cell therapy has revolutionized treatment for blood cancers. For multiple myeloma, CAR T therapies targeting BCMA have already been FDA-approved—but now, GPRC5D-targeted CAR T cells are emerging as a strong next wave.
These new CAR T therapies are being evaluated in clinical trials for patients with relapsed or refractory multiple myeloma (RRMM). Preliminary data shows that GPRC5D CAR T may offer similar—or even improved—remission rates, without some of the resistance issues seen in BCMA-targeted therapies.
What Patients Should Know
If you’re living with multiple myeloma—or have been diagnosed with MGUS or SMM—ask your care team about clinical trials involving GPRC5D antibody therapy or CAR T-cell treatment. These cutting-edge therapies are only available at select centers today, but they may represent the future standard of care.
Stay informed, ask questions, and explore options early.