[Purpose]

This study aims to assess the efficacy of immunotherapeutic agents in real clinical settings by comparing the treatment outcomes of relapsed/refractory multiple myeloma patients treated with immunotherapeutic agents and classical immunotherapeutic agents.

[Primary Study Objective] Compare the overall survival duration among patients based on the administered treatments.

[Secondary Study Objectives] Compare the progression-free survival duration among patients based on the administered treatments.

Compare the response rates among patients based on the administered treatments. Compare the healthcare costs associated with the administered treatments among patients.

[Study Participants]

Patients diagnosed with plasma cell disorders (PCD) at Seoul St. Mary's Hospital, Yeouido St. Mary's Hospital, Incheon St. Mary's Hospital, and Eunpyeong St. Mary's Hospital from May 2009 to June 2023.

- Selection Criteria

1. Patients diagnosed with multiple myeloma at Seoul St. Mary's Hospital, Yeouido St. Mary's Hospital, Incheon St. Mary's Hospital, and Eunpyeong St. Mary's Hospital from May 2009 to June 2023.

2. Age 19 and above.

3. Patients who have undergone immunotherapy* for the purpose of treating relapsed/refractory multiple myeloma.

   *Immunotherapy is defined as one of the following drugs depending on the treatment timeline:Proteasome inhibitor, immune modulatory drug, monoclonal antibody, Chimeric Antigen Receptor T-cell therapy (CAR-T), bispecific antibody, antibody-drug conjugate.

4. Exclusion Criteria:

   Patients diagnosed with conditions other than monoclonal gammopathy of undetermined significance (MGUS) or multiple myeloma.

5. Data Collection Period for Study Participants : April 1, 2009, to June 30, 2023.

[ Study plan] This study is a cross-sectional study that includes all patients who meet the selection criteria for a specific period.

All participants meeting the selection criteria are included in the study and investigated for the items.

Among the study participants, patients who received immunotherapy agents defined as immune checkpoint inhibitors are identified as the experimental group.

The entire cohort is initially defined as the control group for the experimental group.

From the initial control group, a final control group is determined by matching with the experimental group based on specific variables, including treatment cycles, in a 1:4 ratio. However, the cohort size for matching can be adjusted during the study. Comparative analyses are conducted between the experimental and control groups, examining baseline variables and outcome variables.

Inclusion Criteria:

1. Patients diagnosed with multiple myeloma at Seoul St. Mary's Hospital, Yeouido St. Mary's Hospital, Incheon St. Mary's Hospital, and Eunpyeong St. Mary's Hospital from May 2009 to June 2023.

2. Age 19 and above.

3. Patients who have undergone immunotherapy* for the purpose of treating relapsed/refractory multiple myeloma.

   • Immunotherapy is defined as one of the following drugs depending on the treatment timeline:

Proteasome inhibitor, immune modulatory drug, monoclonal antibody, Chimeric Antigen Receptor T-cell therapy (CAR-T), bispecific antibody, antibody-drug conjugate.

Exclusion Criteria:

• Patients diagnosed with conditions other than monoclonal gammopathy of undetermined significance (MGUS) or multiple myeloma.

Patients diagnosed with plasma cell disorders (PCD) at Seoul St. Mary's Hospital, Yeouido St. Mary's Hospital, Incheon St. Mary's Hospital, and Eunpyeong St. Mary's Hospital from May 2009 to June 2023.