CALR-mutated patients with low allele burden represent a specific subtype of essential thrombocythemia: A study on behalf of FIM and GBMHM

A low allele burden (i.e., <20%) of the CALR driver mutation is found in 10.8% of CALR-mutated MPNs, mostly in essential thrombocythemia, and correlates with a milder phenotype and a more indolent evolution compared to patients with an allele burden ≥20%.

In Multiple Myeloma, High-Risk Secondary Genetic Events Observed at Relapse Are Present From Diagnosis in Tiny, Undetectable Subclonal Populations

PURPOSE

Multiple myeloma (MM) is characterized by copy number abnormalities (CNAs), some of which influence patient outcomes and are sometimes observed only at relapse(s), suggesting their acquisition during tumor evolution. However, the presence of micro-subclones may be missed in bulk analyses. Here, we use single-cell genomics to determine how often these high-risk events are missed at diagnosis and selected at relapse.

MATERIALS AND METHODS

We analyzed 81 patients with plasma cell dyscrasias using single-cell CNA sequencing. Sixty-six patients were selected at diagnosis, nine at first relapse, and six in presymptomatic stages. A total of 956 newly diagnosed patients with MM and patients with first relapse MM have been identified retrospectively with required cytogenetic data to evaluate enrichment of CNA risk events and survival impact.

RESULTS

A total of 52,176 MM cells were analyzed. Seventy-four patients (91%) had 2-16 subclones. Among these patients, 28.7% had a subclone with high-risk features (del(17p), del(1p32), and 1q gain) at diagnosis. In a patient with a subclonal 1q gain at diagnosis, we analyzed the diagnosis, postinduction, and first relapse samples, which showed a rise of the high-risk 1q gain subclone (16%, 70%, and 92%, respectively). In our clinical database, we found that the 1q gain frequency increased from 30.2% at diagnosis to 43.6% at relapse (odds ratio, 1.78; 95% CI, 1.58 to 2.00). We subsequently performed survival analyses, which showed that the progression-free and overall survival curves were superimposable between patients who had the 1q gain from diagnosis and those who seemingly acquired it at relapse. This strongly suggests that many patients had 1q gains at diagnosis in microclones that were missed by bulk analyses.

CONCLUSION

These data suggest that identifying these scarce aggressive cells may necessitate more aggressive treatment as early as diagnosis to prevent them from becoming the dominant clone.

Biallelic deletion of 1p32 defines ultra-high-risk myeloma, but monoallelic del(1p32) remains a strong prognostic factor

Cytogenetic abnormalities (CAs) are known to be the preponderant prognostic factor in multiple myeloma. Our team has recently developed a prognostic score based on 6 CAs, with which del(1p32) appears to be the second worst abnormality after del(17p). This study aimed to confirm the adverse effect of 1p32 deletion in patients with newly diagnosed multiple myeloma (NDMM). Among 2551 patients with newly diagnosed multiple myeloma, 11% were harboring del(1p32). Their overall survival (OS) was significantly inferior compared with patients without del(1p32) (median OS: 49 months vs 124 months). Likewise, progression-free survival was significantly shorter. More importantly, biallelic del(1p32) conferred a dramatically poorer prognosis than a monoallelic del(1p32) (median OS: 25 months vs 60 months). As expected, the OS of patients with del(1p32) significantly decreased when this abnormality was associated with other high-risk CAs [del(17p), t(4;14), or gain(1q)]. In the multivariate analysis, del(1p32) appeared as a negative prognostic factor; after adjustment for age and treatment, the risk of progression was 1.3 times higher among patients harboring del(1p32), and the risk of death was 1.9 times higher. At the dawn of risk-adapted treatment strategies, we have confirmed the adverse effect of del(1p32) in multiple myeloma and the relevance of its assessment at diagnosis.

Heterogeneity in long term outcomes for R-ISS stage II in newly diagnosed multiple myeloma patients

In the era of personalized treatment in multiple myeloma, high-risk patients must be accurately defined. The International Myeloma Working Group recommends using the Revised International Staging System (R-ISS) to identify high-risk patients. The main purpose of our work was to explore the heterogeneity of outcome among R-ISS stage II patients assessing the impact of ISS, chromosomal abnormalities (CA) and LDH level in this subgroup. Data were issued from 1,343 newly diagnosed myeloma patients up to 65 years, enrolled in 3 clinical trials implemented by the Intergroupe Francophone du Myelome. All patients were eligible to an intensive treatment. Patients R-ISS stage II but ISS stage I had 1.6 times more risk of death than patients R-ISS stage I (adjusted HR 1.6; 95% CI, 1.1 to 2.2; P = .01) and patients R-ISS stage II but ISS stage III had a better overall survival than patients R-ISS stage III (adjusted HR 0.7; 95% CI, 0.4 to 0.9, P = .02). However, among patients classified in R-ISS II, ISS stage and CA (del(17p) and t(4;14)) were still relevant prognostic factors for death. Dividing R-ISS stage II into 3 subgroups: ISS I with standard risk CA, ISS II or III with standard risk CA and, high risk CA patients, median overall survivals were respectively not reached, 112 and 71 months (P < 0.001). In conclusion, stratification of patients in the R-ISS stage II group can be improved by taking into account CA and ISS. However, this does not improve predictive performance of survival models.

Efficacy of lenalidomide in myelodysplastic/myeloproliferative neoplasms with ring sideroblasts and an extreme platelet count

Lenalidomide is efficient in reducing red blood cell transfusion dependency and markedly lowering platelet counts in MDS/MPN-RS-T in the context of major platelet counts.

Idelalisib in a patient with refractory Waldenström's macroglobulinemia complicated by anuric renal failure: a case report

Background

Waldenström’s macroglobulinemia is a rare B-cell lymphoma. The gold standard treatment for Waldenström’s macroglobulinemia is an anti-CD20 antibody (rituximab) in combination with alkylating agents and dexamethasone. Treatment targeting the B-cell receptor such as ibrutinib (but not idelalisib) is currently approved for treatment of patients with relapsed or refractory Waldenström’s macroglobulinemia.

Case presentation

We report a case of a 71-year-old white French man with Waldenström’s macroglobulinemia who presented with acute renal failure and hyperviscosity syndrome. His Waldenström’s macroglobulinemia was refractory to first-line treatment with rituximab, cyclophosphamide, and dexamethasone. Because of his hemorrhagic syndrome and medical history of recent myocardial infarction, we decided to treat him with idelalisib 150 mg twice daily instead of ibrutinib. We observed a very quick improvement in the patient’s clinical status without need for dose adjustment.

Conclusion

Our patient’s case provides the first evidence, to the best of our knowledge, that idelalisib may be an efficient treatment option for patients with Waldenström’s macroglobulinemia complicated by anuric renal failure and in whom ibrutinib is contraindicated.