[Mark11]

Article comparing ASO & MFC MRD testing methods

by Mark11 on Fri Oct 17, 2014 3:37 pm

For those interested in MRD (minimal residual testing) for myeloma, there was a recent paper that I thought was interesting. The study is a comparison between ASO-PCR (molecular) and flow cytometry testing for MRD. Flow cytometry is what Black Swan is promoting. At this point ASO-PCR (molecular) is still the more sensitive test according to this study.

Here is reference and accompanying abstract.

R Silvennoinen et al, "Comparative analysis of minimal residual disease detection by multiparameter flow cytometry and enhanced ASO RQ-PCR in multiple myeloma," Blood Cancer Journal, Oct 10, 2014

Abstract:

Multiparameter flow cytometry (MFC) and allele-specific oligonucleotide real-time quantitative PCR (ASO RQ-PCR) are the two most sensitive methods to detect minimal residual disease (MRD) in multiple myeloma (multiple myeloma). We compared these methods in 129 paired post-therapy samples from 22 unselected, consecutive multiple myeloma patients in complete/near complete remission.

Appropriate immunophenotypic and ASO RQ-PCR-MRD targets could be detected and MRD analyses constructed for all patients. The high PCR coverage could be achieved by gradual widening of the primer sets used for clonality detection. In addition, for 13 (55%) of the patients, reverse orientation of the ASO primer and individual design of the TaqMan probe improved the sensitivity and specificity of ASO RQ-PCR analysis.

A significant nonlinear correlation prevailed between MFC-MRD and PCR-MRD when both were positive. Discordance between the methods was found in 32 (35%) paired samples, which were negative by MFC-MRD, but positive by ASO RQ-PCR.

The findings suggest that with the described technique, ASO RQ-PCR can be constructed for all patients with multiple myeloma. ASO RQ-PCR is slightly more sensitive in MRD detection than 6−10-color flow cytometry. Owing to technical demands ASO RQ-PCR could be reserved for patients in immunophenotypic remission, especially in efficacy comparisons between different drugs and treatment modalities."

[goldmine848]

Re: Article comparing ASO & MFC MRD testing methods

by goldmine848 on Fri Oct 17, 2014 9:32 pm

What is immuno­pheno­typic remission?

[blair77]

Re: Article comparing ASO & MFC MRD testing methods

by blair77 on Fri Oct 17, 2014 9:38 pm

My husband had a bone marrow biopsy today using a test called Clonosight it is supposed to measure MRD. Has anyone heard of it?

[Dr. Peter Voorhees]

Re: Article comparing ASO & MFC MRD testing methods

by Dr. Peter Voorhees on Sun Oct 19, 2014 12:25 pm

Dear all,

The optimal test for MRD remains the subject of ongoing investigation, and the clinical relevance of differences in results remains to be fully understood.

Sequencing based techniques such as ASO appear to be more sensitive for trace levels of disease than multiparamtetric flow cytometry (MFC). However, there is no good data on long-term outcomes / survival for those patients who are MRD negative by flow cytometry but MRD positive by sequencing-based strategies compared with those that have MRD negative status by both tests.

Immunophenotypic CR means MRD negative by flow cytometry.

The Clonosight test uses a sequencing based technique to determine MRD status.

Both tests are very good at assessing the depth of response.

I hope this helps.

Thanks!

Pete V.