# Personalized Treatment for Newly Diagnosed Multiple Myeloma: How Measuring Residual Cancer Cells Guides Therapy Choices

## Table of Contents

- Key Points
- Introduction: Why This Research Matters
- Study Design and Methods
- Who Participated in the Study
- Key Findings: What the Research Discovered
- Treatment Safety and Side Effects
- What This Means for Patients
- Study Limitations
- Recommendations for Patients
- Frequently Asked Questions
- Source Information

## Key Points

- MRD-negative patients after initial therapy had similar outcomes with or without stem cell transplantation.
- MRD-positive patients did not benefit more from tandem transplantation than single transplant plus medication.
- The MIDAS study used next-generation sequencing to detect as few as 1 cancer cell per 100,000 normal cells.
- Treatment decisions based on MRD status may help patients avoid unnecessary transplantation and its side effects.

## Introduction: Why This Research Matters

Multiple myeloma is a cancer of plasma cells in the bone marrow that affects thousands of people each year. For patients who are eligible for stem cell transplantation, the current standard treatment involves four-drug combination therapy followed by autologous stem cell transplantation (ASCT), where patients receive their own stem cells after high-dose chemotherapy.

Recently, doctors have discovered that measuring very small amounts of remaining cancer cells, called measurable residual disease (MRD), can predict how well patients will do long-term. Patients who achieve MRD-negative status (meaning no detectable cancer cells at a very sensitive level) have better outcomes than those who still have detectable disease.

This large clinical trial, called the MIDAS study, aimed to determine whether treatment decisions could be personalized based on MRD status after initial therapy. The researchers wanted to know if patients with no detectable disease could avoid transplantation and still do well, and whether patients with remaining disease would benefit from more intensive treatment with tandem (double) transplants.

## Study Design and Methods

This was a phase 3 clinical trial conducted across 72 medical centers in France and Belgium between December 2021 and July 2023. The study enrolled 791 patients with newly diagnosed multiple myeloma who were eligible for stem cell transplantation.

All patients received the same initial treatment consisting of six 28-day cycles of four medications:

- Isatuximab (an anti-CD38 monoclonal antibody)
- Carfilzomib (a proteasome inhibitor)
- Lenalidomide (an immunomodulatory drug)
- Dexamethasone (a steroid)

After this induction therapy, researchers measured MRD status using highly sensitive next-generation sequencing that can detect as few as 1 cancer cell among 100,000 normal cells (sensitivity level of 10^-5).

Patients were then divided into two groups based on their MRD results:

1.
**MRD-negative patients** (no detectable cancer): Randomly assigned to either receive ASCT plus 2 cycles of medication (242 patients) OR receive 6 additional cycles of medication without transplantation (243 patients)
1.
**MRD-positive patients** (detectable cancer): Randomly assigned to either receive tandem ASCT (double transplantation, 124 patients) OR receive single ASCT plus 2 cycles of medication (109 patients)

The main goal was to see how many patients achieved an even deeper MRD-negative status (1 cancer cell per million normal cells, sensitivity level of 10^-6) before starting maintenance therapy.

## Who Participated in the Study

The study included 718 patients who completed the initial therapy and were randomized into the different treatment groups. The average age was 59 years (ranging from 25 to 66 years), and 57% of participants were men.

Patients had varying stages of disease:

- 13% had International Staging System (ISS) stage III disease (more advanced)
- 5% had Revised International Staging System (R-ISS) stage III disease
- 8% had high-risk disease based on genetic features
- 17% had high-risk disease according to International Myeloma Society criteria

The treatment groups were well-balanced in terms of age, disease characteristics, and genetic risk factors, making the comparisons between treatments valid and reliable.

## Key Findings: What the Research Discovered

**For MRD-negative patients after induction:** Among the 485 patients who had no detectable disease after initial therapy, the results showed no significant difference between the two treatment approaches. In the group that received transplantation plus 2 cycles of medication, 86% achieved the deeper MRD-negative status (1 cancer cell per million). In the group that received 6 additional cycles of medication without transplantation, 84% achieved this deep remission.

The statistical analysis showed an adjusted relative risk of 1.02 with a 95% confidence interval of 0.95 to 1.10, and a P-value of 0.64, indicating no statistically significant difference between the two approaches.

**For MRD-positive patients after induction:** Among the 233 patients who still had detectable disease after initial therapy, the more intensive tandem transplantation approach did not perform better than the single transplantation approach. In the tandem transplantation group, 32% achieved deep MRD-negative status, while in the single transplantation plus medication group, 40% achieved this outcome.

The statistical analysis showed an adjusted relative risk of 0.82 with a 95% confidence interval of 0.58 to 1.15, and a P-value of 0.31, indicating no statistically significant difference. Importantly, 15% of patients in the tandem transplantation group did not receive the second transplant, primarily due to treatment-related complications or patient choice.

The researchers also tracked how MRD status changed during treatment. They found that some patients converted from MRD-positive to MRD-negative during consolidation therapy (53 in the transplantation group and 42 in the medication-only group), while a small number lost their MRD-negative status (6 and 10 patients respectively).

## Treatment Safety and Side Effects

During the consolidation treatment phase, the study recorded several serious events:

- 5 patients experienced disease progression
- 2 patients died from causes unrelated to disease progression
- All these serious events occurred in the medication-only group (for MRD-negative patients) and the tandem transplantation group (for MRD-positive patients)

The researchers reported that no new safety concerns emerged beyond what was already known about these treatments. The side effects were consistent with previously documented profiles of these medications and transplantation procedures.

The median follow-up time was 16.8 months for the MRD-negative patient groups and 16.3 months for the MRD-positive patient groups, providing substantial medium-term safety data.

## What This Means for Patients

This research provides important evidence that treatment for newly diagnosed multiple myeloma can be personalized based on response to initial therapy. For patients who achieve deep remission after initial four-drug therapy, continuing with medication alone may be equally effective as undergoing stem cell transplantation.

This is particularly significant because stem cell transplantation involves higher doses of chemotherapy, more side effects, and longer recovery times. If equally effective outcomes can be achieved without transplantation, many patients may avoid these additional challenges.

For patients who still have detectable disease after initial therapy, the study suggests that the more intensive tandem transplantation approach does not provide better results than single transplantation followed by additional medication. This is important because tandem transplantation is more demanding on patients and carries higher risks.

The findings support the growing movement toward response-adapted therapy in multiple myeloma, where treatment decisions are guided by how patients respond to initial therapy rather than applying the same approach to everyone.

## Study Limitations

While this study provides valuable insights, it's important to understand its limitations:

- The follow-up period of approximately 16 months is relatively short for multiple myeloma, which often requires longer observation to fully understand survival outcomes
- The study was conducted primarily in France and Belgium, and results might vary in different populations or healthcare systems
- 15% of patients assigned to tandem transplantation did not receive the second transplant, which might affect the results
- The researchers did not collect data on race and ethnicity due to European data protection regulations, so we don't know if results varied across different demographic groups

The study is ongoing, and researchers continue to follow patients to gather longer-term data on survival and disease progression, which will provide more complete information about the lasting benefits of these treatment approaches.

## Recommendations for Patients

If you or a loved one has been diagnosed with multiple myeloma, here's what this research means for you:

1.
**Ask about MRD testing:** Discuss with your doctor whether measurable residual disease testing is appropriate for your situation after initial treatment
1.
**Understand your options:** If you achieve deep remission after initial therapy, know that continuing with medication alone may be a valid alternative to stem cell transplantation
1.
**Consider the trade-offs:** Weigh the potential benefits and risks of different approaches - transplantation may involve more side effects but medication-only approaches require longer treatment duration
1.
**Participate in shared decision-making:** Work with your healthcare team to choose the approach that best aligns with your personal preferences, values, and tolerance for different treatment intensities
1.
**Stay informed:** Continue to follow research updates as longer-term results from this and similar studies become available

Always remember that treatment decisions should be made in consultation with your medical team, considering your specific disease characteristics, overall health, and personal preferences.

## Frequently Asked Questions

### What is measurable residual disease (MRD) in multiple myeloma?

Measurable residual disease (MRD) refers to very small amounts of cancer cells that remain in the bone marrow after treatment, detectable only by highly sensitive tests. In the MIDAS study, MRD was measured using next-generation sequencing that can find as few as 1 cancer cell among 100,000 normal cells. Achieving MRD-negative status means no cancer cells are detected at that sensitivity level, which is associated with better long-term outcomes.

### Can I avoid stem cell transplant if my MRD is negative after initial therapy?

According to the MIDAS study, patients with newly diagnosed multiple myeloma who achieved MRD-negative status after initial four-drug therapy had similar deep remission rates whether they received stem cell transplantation plus medication or continued with medication alone. The study found no statistically significant difference between the two approaches, suggesting that for MRD-negative patients, continuing medication without transplantation may be equally effective.

### Why does multiple myeloma come back after treatment?

Multiple myeloma can return after treatment because some cancer cells may survive initial therapy, even if they are not detected by standard tests. The MIDAS study tracked MRD status and found that a small number of patients lost their MRD-negative status during consolidation therapy, indicating that residual disease can persist or re-emerge. This is why ongoing monitoring and longer-term follow-up are important to understand disease progression and treatment durability.

### What is the MIDAS study and who was eligible to participate?

The MIDAS study was a phase 3 clinical trial in France and Belgium that enrolled 791 patients with newly diagnosed multiple myeloma who were eligible for stem cell transplantation. Participants received initial treatment with isatuximab, carfilzomib, lenalidomide, and dexamethasone. After this, their residual cancer was measured, and they were assigned to different treatment strategies based on whether they had detectable disease.

### How is measurable residual disease (MRD) measured in multiple myeloma?

MRD is measured using highly sensitive next-generation sequencing that can detect as few as 1 cancer cell among 100,000 normal cells, which is a sensitivity level of 10^-5. This test is done after initial therapy to determine if any cancer cells remain. A deeper level of MRD negativity, at 10^-6, means detecting 1 cancer cell per million normal cells.

### What happens if I have no detectable cancer cells after initial therapy for multiple myeloma?

If you have no detectable cancer cells after initial therapy, you may have the option to continue with medication alone instead of undergoing stem cell transplantation. In the MIDAS study, patients who received six additional cycles of medication without transplant achieved deep remission at a similar rate (84%) as those who had a transplant plus two cycles (86%). This suggests medication-only may be equally effective.

### What happens if I still have detectable cancer cells after initial therapy?

If you still have detectable cancer cells after initial therapy, the MIDAS study found that a more intensive approach with tandem (double) stem cell transplants did not perform better than a single transplant followed by additional medication. Deep MRD-negative status was achieved in 32% of the tandem group versus 40% in the single transplant group, showing no significant benefit from the more intensive approach.

## Source Information

**Original Article Title:** Measurable Residual Disease–Guided Therapy in Newly Diagnosed Myeloma

**Authors:** A. Perrot, J. Lambert, C. Hulin, A. Pieragostini, L. Karlin, B. Arnulf, P. Rey, L. Garderet, M. Macro, M. Escoffre-Barbe, J. Gay, T. Chalopin, R. Gounot, J.-M. Schiano, M. Mohty, X. Leleu, S. Manier, C. Mariette, C. Chaleteix, T. Braun, B. De Prijck, H. Avet-Loiseau, J.-Y. Mary, J. Corre, P. Moreau, and C. Touzeau for the MIDAS Study Group

**Publication:** New England Journal of Medicine, July 31, 2025, Volume 393, Number 5

**DOI:** 10.1056/NEJMoa2505133

**Note:** This patient-friendly article is based on peer-reviewed research published in one of the world's leading medical journals. The information has been simplified for educational purposes but maintains all the key findings and data from the original study.


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