Multiple myeloma, which occurs when cancer cells invade the bones, is one of the three major blood cancers along with malignant lymphoma and leukemia. According to the Health Insurance Review & Assessment Service (HIRA), the number of patients visiting hospitals due to multiple myeloma last year was 11,219, which is double that of ten years ago. More than 80% of patients are over 60 years old. As the aging process accelerates, the number of patients is also increasing.
Seoul St. Mary's Hospital opened the country's first blood disease hospital in 2018 by expanding and reorganizing its existing hematopoietic stem cell transplant center. Last month, the hospital attracted significant attention in the medical community by releasing 12 years' worth of treatment results for multiple myeloma patients. This is because the survival rate of multiple myeloma patients treated at the blood disease hospital far exceeded that of all multiple myeloma patients in the country.
During an appointment on the 21st at Seoul St. Mary's Hospital in Seocho-gu, Seoul, Professor Min Chang-gi of the hematology department at the Catholic University of Korea Seoul St. Mary's Hospital's Multiple Myeloma Center said, "Multiple myeloma, which has been regarded as an incurable cancer, is seeing treatment outcomes improve due to advancements in treatment technologies and drugs. I hope patients and their families do not lose heart."
Multiple myeloma is a blood cancer that occurs in the bone marrow, which fills the inner space of bones. When plasma cells, which are immune cells that make antibodies, abnormally proliferate and turn into cancer cells, they destroy bones and cause anemia, kidney damage, and immune dysfunction. The exact cause of the disease has not yet been determined. Professor Min explained, "While some associations with radiation, pesticides, benzene, or metal-related industries have been reported, a direct correlation has not been scientifically proven."
Research conducted by Professors Min Chang-gi, Park Seong-su, Lee Jeong-yeon, and Byeon Seong-kyu at Seoul St. Mary's Hospital analyzed the treatment results for 1,291 multiple myeloma patients treated from 2010 to 2021, revealing that the median overall survival (OS) of the patients was 80.5 months. OS refers to the period from the start of treatment until death.
These results represent the first systematic analysis and release of long-term treatment outcomes for multiple myeloma, showing numbers far superior to previous records. The median overall survival of all multiple myeloma patients in the country, announced by the Health Insurance Review & Assessment Service (HIRA), was 33.6 months from 2009 to 2012, 44.6 months from 2013 to 2016, and 52.8 months from 2017 to 2020.
Professor Min stated, "I believe that instead of merely administering chemotherapy according to symptoms, it leads to better outcomes when we strategically customize treatment by comprehensively assessing the vulnerabilities of each patient."
The treatment for multiple myeloma mainly employs methods to replace cancerous cells with normal cells. Professor Min explained, "The treatment method varies depending on the patient's age and health status," adding, "Typically, autologous hematopoietic stem cell transplants are performed for relatively healthy patients under 70 years old." This involves removing the patient’s blood marrow, emptying it with medication, and then reinfusing the patient's previously collected stem cells.
However, older patients or those with comorbidities often find transplantation difficult. In such cases, conventional chemotherapy agents are combined with immunomodulators, proteasome inhibitors, and monoclonal antibodies. Nonetheless, many patients experience relapse after transplantation or develop resistance to existing medications. Professor Min explained that new treatments capable of addressing such relapsed and refractory patients are emerging.
In particular, recent innovative therapies utilizing the human immune system are changing the landscape of multiple myeloma treatment. Professor Min noted, "Immunotherapies like CAR-T cell therapy or bispecific antibody therapy that can precisely target cancer cells are becoming pivotal points in overcoming the limitations of existing treatments."
In CAR-T cells, "CAR" stands for chimeric antigen receptor. The term CAR-T cell refers to a method where T cells, which are immune cells, are modified with a gene that helps identify the antigens on cancer cell surfaces, similar to how a creature in Greek mythology has the features of multiple animals. T cells are extracted from the patient's blood, genetically modified outside the body to recognize cancer cells, and then reinfused back into the body. Unlike other chemotherapy agents, CAR-T cells attack only cancer cells, leaving normal tissues unharmed, resulting in superior therapeutic effects.
Professor Min remarked, "CAR-T therapy shows a high response rate even in relapsed or refractory patients who have failed previous treatments, and there are cases of complete remission." Complete remission is different from a cure; a cure refers to a state where all symptoms disappear and no further medications or treatments are needed, while complete remission means maintaining health so that symptoms do not reappear with appropriate treatments or medications.
The challenge is that CAR-T cells can only be created if the patient goes to a specialized facility, which incurs significant time and expense. This issue is also causing supply shortages in the United States. Particularly in Korea, it remains a mere dream, as although approval has been granted, foreign pharmaceutical companies do not supply it. Professor Min stated, "In clinical trials, CAR-T has consistently shown good responses with just one treatment, but it remains difficult to use in actual practice in Korea due to the lack of supply."
The bispecific antibody therapy, another type of immune chemotherapy, has advantages over CAR-T in this regard. A bispecific antibody is one that simultaneously recognizes and binds to two different antigens. It grabs one cancer cell with one hand and pulls in an immune cell with the other hand, inducing an immune response. As a result, it can provoke a much stronger immune response than conventional monoclonal antibodies.
Professor Min stated, "Bispecific antibody therapy is much more accessible since it can be administered immediately, unlike CAR-T, and the treatment response is quite good. It is widely used in actual clinical practice."
Multiple myeloma frequently relapses after treatment. Professor Min mentioned that the Multiple Myeloma Center focuses on careful management even after treatment. He noted, "Close cooperation with departments like infectious diseases and intensive care units is also crucial for the management of multiple myeloma."
Professor Min stated, "The most important thing I want to urge my patients is to not lose heart." He added, "Please remember that good treatments are continuously being developed and that many patients are successfully surviving after treatment."