MRD / molecular residual disease testing

CEPHEUS extends the quadruplet standard to patients who are not going to transplant, closing the gap between transplant-eligible and ineligible populations. It is also one of the first phase 3 trials to be designed around MRD-negativity as the primary endpoint, which could shorten future myeloma trials by years. Frailer patients still need dose-adapted approaches.

After bladder removal, a blood test can now tell who needs immunotherapy and who can safely be spared it. This is the model for MRD-guided adjuvant therapy across cancers: treat the blood-positive, watch the blood-negative.

E1910 changed the standard of care for adult B-ALL: immunotherapy is now part of front-line consolidation even for patients with no detectable leukaemia, because MRD-negative by flow cytometry does not mean cured. It also demonstrated that a T-cell engager can improve overall survival in a curative setting. Chemotherapy-light or chemotherapy-free regimens built on blinatumomab and inotuzumab are the next step.

PERSEUS, with the earlier GRIFFIN and CASSIOPEIA trials, made a four-drug daratumumab quadruplet the standard for fit patients heading to transplant. It also introduced MRD-directed stopping of the antibody, a step towards treatment that is deep but not indefinite. Whether transplant itself remains necessary on top of a quadruplet is now the open question.

The blood test stratifies risk far better than stage or pathology. It supports treating ctDNA-positive patients and suggests ctDNA-negative patients gain little from chemotherapy, but because treatment was not randomised the de-escalation claim needs the randomised trials that are now under way.

Relapse after surgery is driven by particular subclones that can be identified in the primary tumour and tracked in blood, which argues for evolution-aware adjuvant strategies. The pollution finding reframes carcinogenesis: some agents promote already-mutant cells rather than causing mutations.

For stage II colon cancer, where most patients are cured by surgery alone, a blood test can identify the minority who benefit from chemotherapy and spare everyone else its side effects. It does not yet prove that treating ctDNA-positive patients improves survival compared with not treating them.

Lung cancers keep evolving after they form, and it is ongoing chromosomal instability rather than the number of mutations that best predicts who will relapse. This gives a rationale for targeting the earliest (clonal) drivers and neoantigens and for tracking evolution in blood after surgery.