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MDS posttransplant gene sequencing prognostic for progression



For patients with myelodysplastic syndrome, gene sequencing of bone marrow samples early after bone marrow transplant with curative intent may provide important prognostic information.

Among 86 patients with myelodysplastic syndrome (MDS), higher maximum variant allele frequency of residual disease–associated mutations at 30 days posttransplantation was significantly associated with disease progression and lower rates of progression-free survival (PFS) at 1 year, reported Eric J. Duncavage, MD, from Washington University in St. Louis, and his colleagues.

“Although this exploratory study has limitations, our results suggest that sequencing-based detection of tumor cells and measurable residual disease after allogeneic hematopoietic stem cell transplantation has prognostic significance for patients with MDS,” they wrote in the New England Journal of Medicine.

Risk of progression was significantly higher among patients who had undergone reduced-intensity conditioning prior to hematopoietic stem cell transplants (HSCT) than among patients who had undergone myeloablative conditioning regimens.

To get a better handle on the significance of molecular predictors of disease progression after HSCT, the authors used enhanced exome sequencing to evaluate paired samples of bone marrow and control DNA from normal skin, and error-corrected sequencing to identify somatic single-nucleotide variant mutations in posttransplant samples.

They detected at least one validated somatic mutation in the pretransplant samples from 86 of 90 patients. Of the 86 patients, 32 had at least one mutation with a maximum variant allele frequency of at least 0.5% detected 30 days after transplantation. The frequency is equivalent to 1 heterozygous mutant cell per 100 cells, the authors explained.

Patients who experienced disease progression had mutations with a median maximum variant allele frequency of 0.9%, compared with 0% for patients who did not have progression (P less than .001).

In all, 53.1% of patients with one or more mutations with a variant allele frequency of at least 0.5% at 30 days had disease progression within a year, compared with 13% of patients who did not have the mutations, even after adjustment for the type of conditioning regimen. The hazard ratio (HR) for disease progression in the patients with mutations was 3.86 (P less than .001).

The association between the presence of one or more mutations with a variant allele frequency of at least 0.5% with increased risk of disease progression was also seen at 100 days, even after adjustment for conditioning regimen (66.7% vs. 0%; HR, 6.52; P less than .001). In multivariable analysis controlling for prognostic scores, maximum variant allele frequency at 30 days, TP53 mutation status and conditioning regimen, the presence of a mutation with at least 0.5% variant allele frequency was associated with a more than fourfold risk of progression, including when the revised International Prognostic Scoring System score and conditioning regimen were considered as covariates. (HR, 4.48; P less than .001),

A separate multivariable analysis of PFS controlling for maximum variant allele frequency at day 30, conditioning regimen, age at transplantation, and type of MDS showed that mutations were associated with a more than twofold risk of progression or death (HR, 2.39; P = .002).

This analysis also showed that secondary acute myeloid leukemia was associated with worse PFS, compared with primary MDS (HR, 2.24; P = .001).

The investigators acknowledged that the high-coverage exome sequencing technique used for the study is not routinely available in the clinic. To control for this, they also looked at their data using a subset of genes that are usually included in gene sequencing panels for MDS and AML.

“Although we identified fewer patients with mutations with the use of this approach than with enhanced exome sequencing, the prognostic value of detection of measurable residual disease was still highly clinically significant,” they wrote.

The study was supported by grants from the Leukemia and Lymphoma Society, Edward P. Evans Foundation, National Cancer Institute, National Institutes of Health, Gabrielle’s Angel Foundation, and the Lottie Caroline Hardy Trust. Dr. Duncavage disclosed personal fees from AbbVie and Cofactor Genomics. The majority of coauthors reported nothing to disclose.

SOURCE: Duncavage EJ et al. N Engl J Med 2018;379:1028-41.

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