Myeloma is a cancer that affects specialised antibody-producing cells called plasma cells.
Over your lifetime, your body produces hundreds of thousands of different types of plasma cells that protect you from a broad range of bacteria and viruses.
The creation of these cells is very precise.
But sometimes, a cell slips through the body’s quality control system and becomes cancerous.
When this happens to cells in the bone marrow, these cells begin to multiply and take up the space normally occupied by bone marrow, where red blood cells are produced.
People with myeloma often experience fatigue because their bodies aren’t making enough red blood cells.
They also report bone pain due to cancer cells eroding the bone.
Proteins produced by these cells can damage the kidneys too.
Typically, myeloma affects people in their sixties to eighties.
Once they’ve been diagnosed with myeloma – often by their primary care clinician – the next step is to see an oncologist to confirm the diagnosis.
Further testing may reveal that they have a premalignant condition called monoclonal gammopathy of undetermined significance (MGUS) or an in-between condition called smouldering myeloma.
Neither of these conditions requires immediate treatment, so patients are monitored by their oncologist.
If patients do need treatment, there are several options to effectively treat the disease.
The choice depends on the person’s age, other medical conditions and which option is a good fit for them.
With optimal treatment, myeloma isn’t immediately life-threatening.
Many patients live for years after their diagnosis, often receiving different treatments over the course of their lives.
Treatments have improved so much in 20 years that some patients are able to reach a typical life expectancy.
One of the standard treatments is a stem cell transplant, also known as a bone marrow transplant.
Stem cells are drawn from the patient, so there’s no need to find a donor.
A stem cell transplant can prolong control of the disease.
Four drugs, in pill or injection form, are also used to treat myeloma alone or in conjunction with a stem cell transplant.
They don’t tend to cause nausea, vomiting or hair loss, and are well tolerated by most patients.
These drugs are:
- Antibodies targeting CD38 – an enzyme present in inflammatory cells and found on the surface of myeloma cells – are injected under the skin to inhibit CD38’s activity.
- Proteasome inhibitor injections affect proteasome – a cell component – from cleaning up excess proteins in the cell.
Myeloma cells produce many proteins, and if the cleaning process is blocked, the cells die.
- Lenalidomide – a thalidomide derivative – given in pill form, acts against the myeloma- affected plasma cells.
- Dexamethasone, also given in pill form, is related to anti-inflammatory drugs like prednisone and cortisone.
- When exposed to dexamethasone, myeloma cells die.
Over the past 20 years, the US Food and Drug Administration (FDA) has approved more than 25 drugs or combinations of drugs for myeloma treatment that have improved on previous options.
In addition to drugs, there are two notable developments: chimeric antigen receptor-T cell therapy (CAR-T cell therapy) and bispecific antibodies.
In CAR-T cell therapy, a person’s own T cells are removed and converted into CAR-T cells.
They’re shipped to a production facility where they’re modified with an “anchor” that allows them to bind to a molecule in a myeloma cell.
CAR-T cells are then reinjected into the patient.
For about three to six months, they hunt down and destroy myeloma cells, eradicating many, if not all, of them.
Some patients may require only one CAR-T cell therapy treatment.
One study found that among patients followed for five years, about one-third never needed additional treatment.
However, this therapy requires a specialised centre, so it isn’t globally available.
But researchers discovered a way to create a similar treatment, i.e. bispecific antibodies.
These can be injected into patients where these antibodies recruit the person’s own T cells to hunt myeloma cells.
These antibodies act like matchmakers, pairing T cells with myeloma cells.
A common side effect of CAR-T cell therapy and bispecific antibody treatments is increased risk of infection due to very low levels of protective antibodies or immunoglobulins.
So part of the treatment includes ensuring they have good immunoglobulin levels.
Both treatments can, in some cases, trigger extreme inflammation.
However, preventive therapies can address this issue.
Also, a small minority of patients can develop a Parkinson’s-like disease.
But by carefully selecting patients and preparing them properly, that risk is greatly reduced.
During and following myeloma treatment, patients typically can go about their lives.
When to begin treatment, as well as the development of new therapies, continues to be explored. – By Dr Rafael Fonseca/Mayo Clinic News Network/Tribune News Service
Dr Rafael Fonseca is a haematologist and oncologist in Phoenix, Arizona, United States.
