We present the case of a 64-year-old man diagnosed with large B-cell lymphoma who relapsed twice after standard-of-care therapy. Due to persisting cytopenia, Next generation sequencing analysis was ...performed, revealing a small
-mutated clone. As a third-line therapy, the patient was treated with CAR-T cells, which resulted in complete remission. However, this treatment also led to the expansion of the
-mutated clone and therapy-related myelodysplasia with a complex aberrant karyotype. This case may serve as a paradigmatic example of clonal hematopoietic progression in a patient undergoing CAR-T cell therapy, especially in the context of a
-mutated clone.
•Wild-type blocking PCR is a sensitive, cost-effective and routinely applicable method for the detection of BTK resistant CLL clones but misses low frequency mutations when using ctDNA.
Resistance ...mutations can be detected in 75% of CLL patients progressing under BTK inhibitor therapy. Using semiquantitative wild-type-blocking (WTB) RT-PCR for BTK and Sanger sequencing for PLCG2 mutations, we compared detection sensitivity of cellular versus circulating tumor DNA (ctDNA) in 20 sample pairs of 13 consecutive patients.
With an assay sensitivity of 0.06%, 7 patients had a BTK-C481S and one a PLCG2-G667E mutation. Cellular DNA was positive in 10 but ctDNA only in 6 samples, giving false-negative results in samples with low mutational burden.
In summary, WTB-PCR is cost-effective and routinely applicable but misses low frequency mutations when using ctDNA.
Dyskeratosis congenita (DKC) is associated with impaired telomere maintenance and with clinical features of premature aging. In this study, we analysed global DNA methylation (DNAm) profiles of DKC ...patients. Age-associated DNAm changes were not generally accelerated in DKC, but there were significant differences to DNAm patterns of healthy controls, particularly in CpG sites related to an internal promoter region of PR domain containing 8 (PRDM8). Notably, the same genomic region was also hypermethylated in aplastic anemia (AA) - another bone marrow failure syndrome. Site-specific analysis of DNAm level in PRDM8 with pyrosequencing and MassARRAY validated aberrant hypermethylation in 11 DKC patients and 27 AA patients. Telomere length, measured by flow-FISH, did not directly correlate with DNAm in PRDM8. Therefore the two methods may be complementary to also identify patients with still normal telomere length. In conclusion, blood of DKC patients reveals aberrant DNAm patterns, albeit age-associated DNAm patterns are not generally accelerated. Aberrant hypermethylation is particularly observed in PRDM8 and this may support identification and classification of bone marrow failure syndromes.
In myeloma patients, high levels of soluble BCMA (sBCMA) can limit the efficacy of BCMA-directed therapies. Belantamab-mafodotin is a BCMA antibody-drug conjugate and shows good overall response ...rates in heavily pretreated patients but progression-free survival data are poor. As the drug induces apoptosis, we hypothesized that sBCMA includes extracellular vesicles (EV) and thus evaluated numbers of BCMA-EV before and during belantamab therapy in 10 myeloma patients. BCMA-EV were significantly higher in patients prior to Belantamab (median: 3227/μl; p = .013) than in other myeloma patients before therapy (n = 10; 1082/μl) or healthy volunteers (n = 10; 980/μl). During therapy, BCMA-EV showed a significant increase to a maximum of 8292/μl (p = .028). Maximal changes in BCMA-EV (Δmax = BCMA-EV at C1/maximal BCMA-EV) showed a strong inverse, logarithmic correlation (r = -.950; p < .001) with FLC ratio changes (Δmax = FLC ratio at C1/minimal FLC ratio) and BCMA-EV peaks often preceded FLC progression. Correlating increase of LDH and BCMA-EV levels, together with clinical symptoms, point to a mafodotin-induced eryptosis. In summary, BCMA-EV are a part of sBCMA, peak levels precede progression, and their measurement might be helpful in identifying resistance mechanisms and side effects of BCMA targeted therapies.
Consent regarding the correct processing and storage of blood microparticles is lacking and different protocols for the freeze-thaw cycle exist. Therefore, three different thawing procedures were ...evaluated regarding their influence on recovery and composition of microparticles. Microparticles were prepared by TRAP-6 or A23187 stimulation of platelet-rich plasma from smokers and nonsmokers (n = 8), from an endothelial cell line or directly obtained from platelet-free plasma of septic patients (n = 5). After snap-freezing in liquid nitrogen platelet-free samples were thawed at 37 degrees, at room temperature or on ice and staining of microparticles was carried out with Annexin V-Cy5 as well as fluorescein isothiocyanate (FITC) or phycoerythrin (PE) labelled antibodies or isotype controls. Microparticle concentrations were determined by means of Trucount tubes. Recovery of platelet microparticles was significantly reduced when samples were thawed on ice (P = 0.001 for all antigens) compared with the two other techniques (P = 0.6 for 37 degrees and P = 0.7 for room temperature, respectively) whereas microparticles of endothelial origin appeared to be less influenced. There was a strong trend towards altered microparticle composition as microparticle counts detected by CD41 staining showed a stronger decrease on ice than Annexin V enumeration (P = 0.07). For microparticle detection thawing of snap-frozen, platelet-free plasma samples should be carried out at room temperature or at 37 degrees C in a water bath but not on ice.
•Atezolizumab, Bevacizumab, Carboplatin and (nab-)Paclitaxel demonstrates high efficacy and moderate toxicity in uncommon EGFR mutations.•Outcome is independent of type of mutation, smoking status, ...PD-L1 expression and prior TKI treatment.•Amivantamab remains a treatment option for Exon 20 insertions after ABCP.
For refractory NSCLC patients with EGFR mutations, recent studies have demonstrated a favorable response to the combination of anti-angiogenic therapy and checkpoint inhibition but included only very few patients with uncommon EGFR mutations for which treatment options are still limited despite new targeted treatments.
Sixteen stage IV NSCLC patients with uncommon EGFR mutations from 9 different German centers were treated in first or further line with Atezolizumab, Bevacizumab, Carboplatin and (nab-)Paclitaxel (ABCP). PFS was evaluated from start of ABCP and OS from time of initial diagnosis of stage IV.
Patients with either an Exon 20 insertion (n = 9) or other uncommon EGFR mutations (n = 7) received ABCP in first, second or further line. Nine patients had received a TKI therapy in first line with an ORR of 66.7 % and a median time-to-next-treatment of 6.7 months. After a median number of 4 ABCP cycles, 4 patients (25.0 %) required a dose reduction of chemotherapy and 5 patients (31.3 %) suffered from grade 3 or 4 toxicity. Overall response rate was 81.3 % and disease control rate 87.5 %. 14 patients (87.5 %) received a maintenance with AB and the median follow-up after initial diagnosis was 24.3 months.
Median PFS was 13.6 months for both the entire cohort and for Exon 20 insertions. Corresponding median OS was either not reached or 30.7 months. Landmark analysis at 12 months gave a PFS of 42.8 % and an OS of 93.3 %. Four patients were rechallenged with ABCP while progressing under maintenance and responded again. In further line therapy, clinical benefit was achieved in all of 3 patients receiving Amivantamab, but in only one of four patients receiving mobocertinib.
In this retrospective analysis, ABCP achieves an encouraging outcome for patients with uncommon EGFR mutations and is a valuable option in the early treatment course.
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