Key Ideas

Indefinite lenalidomide maintenance after transplant has been standard practice in multiple myeloma for years, largely on the strength of older trials that never directly tested whether stopping was safe. Newer trials using sensitive minimal residual disease (MRD) testing now show that many standard-risk patients who reach deep, sustained MRD negativity can safely stop treatment, sparing them years of unnecessary toxicity without compromising outcomes.

A Practice Built on an Old Assumption

Post-transplant maintenance therapy in multiple myeloma has followed one basic rule for years, regardless of how deep a remission a patient reaches: keep going until progression. That rule made sense when there was no reliable way to know how much disease remained after treatment. It is worth asking whether it still makes sense now that testing can detect one myeloma cell among a million normal marrow cells.

Consider a patient followed from smoldering to active myeloma who received induction chemotherapy, achieved a good response, underwent autologous hematopoietic cell transplant, and started lenalidomide maintenance. Years later, MRD testing returns negative at a sensitivity of one in a million cells. The reflexive answer has always been to continue treatment anyway, because that is what the older trials, run before deep MRD testing existed, seemed to support. But newer data suggest that reflex deserves reconsideration.

Why Indefinite Maintenance Became the Default

Guideline recommendations from major centers, including Mayo Clinic's mSMART recommendations, have generally called for maintenance therapy to continue until disease progression, and that stance has real trial support behind it. An early randomized comparison of lenalidomide-dexamethasone for a fixed 18 cycles versus continuous therapy showed better median progression-free survival with continuous treatment, though overall survival did not differ significantly. European maintenance studies have generally used finite-duration lenalidomide, while United States practice has defaulted to indefinite treatment, and when compared directly using the same induction, transplant, and maintenance backbone, limited-duration maintenance produced median progression-free survival of roughly 47 months versus 68 months with indefinite therapy. That gap has, understandably, kept most practices on the side of continuing treatment.

What Deep MRD Testing Changes

Two developments have shifted this calculus. First, MRD assays have become considerably more sensitive. Flow cytometry can detect residual disease down to roughly one cell in 100,000, without requiring the original diagnostic bone marrow sample to identify the myeloma clone, which matters when older biopsy material is unavailable or too degraded for clonal identification. Next-generation sequencing pushes sensitivity to one cell in a million, offering a materially deeper look at remission than protein-level testing or marrow cell counts alone ever could.

Second, and more directly relevant to the stopping question, the ECOG-ACRIN ENDURANCE trial provided the most direct randomized comparison of maintenance duration to date. Enrolling standard-risk patients without high-risk cytogenetics such as del17p, t(14;16), or t(14;20), the trial randomized 516 patients who had completed induction to either indefinite lenalidomide or a fixed two years of treatment. Median progression-free survival was 42.5 months with indefinite maintenance versus 38.9 months with the two-year limited course, but seven-year overall survival was essentially identical between the arms, around 69% in both. Indefinite treatment also came with a higher rate of grade 3 or higher nonhematologic toxicity and a higher five-year incidence of second primary malignancies, 11.2% versus 8.3%. In other words, more than four additional years of lenalidomide bought no measurable survival benefit for standard-risk patients, only more toxicity.

Building the Case for De-escalation

Several other trials point in the same direction. A study comparing continued lenalidomide-dexamethasone against dropping the dexamethasone component while keeping lenalidomide alone found the de-intensified approach performed at least as well, reinforcing the idea that more therapy does not automatically translate into better outcomes and can instead add toxicity without added benefit. Separately, trials establishing that two-drug maintenance produces deeper MRD negativity than one-drug approaches, and that patients who reach sustained MRD negativity on repeat testing can often stop therapy entirely without early relapse, have built a growing evidence base for MRD-guided de-escalation across the treatment course, not just at the maintenance stage.

The SWOG DRAMMATIC trial (S1803) was designed specifically to test this question in a randomized fashion: patients are randomized to lenalidomide alone or lenalidomide plus daratumumab as post-transplant maintenance, with MRD testing at two years used to guide a second randomization between continuing or stopping maintenance in patients who are MRD negative. Results are still years away, but the trial design itself reflects how far the field has moved toward accepting MRD status as a legitimate basis for treatment decisions rather than treating indefinite therapy as the only defensible default.

An MRD-Guided Approach in Practice

For standard-risk patients who achieve MRD negativity on daratumumab-lenalidomide maintenance, one reasonable approach is stopping the daratumumab component at two years, then rechecking MRD status a year later and stopping lenalidomide as well if no disease is detected. Patients who discontinue therapy this way still warrant close follow-up: labs and clinic visits roughly every three months, with a repeat bone marrow MRD assessment about a year after stopping. If MRD remains negative, the approach has worked; if MRD turns positive or the patient's clinical picture changes, restarting maintenance remains straightforward, since time from MRD conversion to clinical relapse generally runs six to twelve months, leaving a reasonable window to act.

High-risk cytogenetics change this calculation considerably. For patients with high-risk disease, sustained MRD negativity is harder to interpret as a stopping signal, since fewer high-risk patients maintain that depth of response once treatment pressure is removed, and continuing maintenance indefinitely remains the more defensible course until better tools exist to identify which high-risk patients might safely de-escalate.

Where the Evidence Still Falls Short

Several open questions remain. It is not yet established whether patients who stay MRD positive should continue the same maintenance regimen, switch to a different one, or intensify treatment. For patients who reach and sustain MRD negativity, the safety of de-escalation over very long follow-up, well beyond the several years captured by trials so far, is still being established. Distinguishing truly high-risk from truly standard-risk disease also remains imperfect despite improved cytogenetic and molecular tools. And when an asymptomatic MRD resurgence occurs in a patient who feels entirely well and does not want to restart treatment, there is not yet a clear answer for what that resurgence should mean for management.

For Patients

For years, patients who reached transplant for multiple myeloma were typically told to expect ongoing maintenance therapy indefinitely, continuing the same medication for as long as it kept working. That approach made sense when doctors had no precise way of knowing how much disease, if any, remained in the body. Newer, far more sensitive tests, capable of finding a single myeloma cell among a million healthy cells taken from the bone marrow, are changing that picture for some patients.

Recent research shows that patients without high-risk genetic features who reach a deep, sustained negative result on this testing may be able to safely stop maintenance therapy after a defined period, rather than continuing indefinitely, without giving up the benefit that treatment provided. This matters because ongoing therapy carries real costs beyond the medication itself: fatigue, blood count changes, a modestly increased risk of second cancers, and the financial and emotional weight of continuous treatment.

Not every patient is a candidate for stopping. Those with higher-risk disease features generally still benefit from continuing maintenance, since deep remissions are harder to sustain in that setting. Anyone on maintenance therapy who is curious whether MRD testing applies to their situation should ask their care team directly, since this is a rapidly evolving area where practice is shifting toward more individualized decisions.

Key Takeaways

  • Indefinite lenalidomide maintenance has been standard practice in multiple myeloma, but the randomized ECOG-ACRIN ENDURANCE trial found no overall survival difference between indefinite and two-year fixed-duration maintenance in standard-risk patients, with more toxicity and second cancers in the indefinite arm.

  • Next-generation sequencing-based MRD testing can now detect residual disease at a sensitivity of one cell in a million, offering a far more precise picture of remission depth than earlier protein- or marrow-based methods.

  • A reasonable MRD-guided approach for standard-risk patients: stop the anti-CD38 antibody component of maintenance first, recheck MRD around three years, and consider stopping lenalidomide if MRD remains negative, with close monitoring afterward.

  • High-risk cytogenetics change the calculation substantially; continuing indefinite maintenance remains the more defensible approach for these patients until better tools exist to identify safe candidates for de-escalation.

  • The ongoing SWOG DRAMMATIC trial (S1803) is testing MRD-guided maintenance duration directly in a randomized design and should provide more definitive answers, though results remain years away.

References

  1. Benboubker L, Dimopoulos MA, Dispenzieri A, et al. Lenalidomide and dexamethasone in transplant-ineligible patients with myeloma. N Engl J Med. 2014;371(10):906-917. doi:10.1056/NEJMoa1402551

  2. Krishnan A, Hoering A, Hari P, Sexton R, Orlowski RZ. Phase III study of daratumumab/rHuPH20 (NSC-810307) plus lenalidomide or lenalidomide as post-autologous stem cell transplant maintenance therapy in patients with multiple myeloma using minimal residual disease to direct therapy duration (DRAMMATIC study): SWOG S1803. Blood. 2020;136(suppl 1):21-22. doi:10.1182/blood-2020-142913

  3. Kumar SK, Jacobus SJ, Cohen AD, et al. Carfilzomib or bortezomib in combination with lenalidomide and dexamethasone for patients with newly diagnosed multiple myeloma without intention for immediate autologous stem-cell transplantation (ENDURANCE): a multicentre, open-label, phase 3, randomised, controlled trial. Lancet Oncol. 2020;21(10):1317-1330. doi:10.1016/S1470-2045(20)30452-6

  4. Kumar S, Jacobus S, Cohen AD, et al. Continuous or fixed-duration maintenance therapy in multiple myeloma. N Engl J Med. 2026;395(3):221-232. doi:10.1056/NEJMoa2600157

  5. Sonneveld P, Dimopoulos MA, Boccadoro M, et al. Daratumumab, bortezomib, lenalidomide, and dexamethasone for multiple myeloma. N Engl J Med. 2024;390(4):301-313. doi:10.1056/NEJMoa2312054