Treatment of Relapsed/Refractory Waldenström Macroglobulinemia Patients: Final Clinical and Molecular Results of the Phase II Brb (Bendamustine, Rituximab and Bortezomib) Trial of the Fondazione Italiana Linfomi (FIL)

Introduction Symptomatic patients with relapsed/refractory Waldenström Macroglobulinemia (RR-WM) treated with standard rituximab plus chemotherapy as second-line salvage therapy, generally show a 18-months progression free survival (PFS) of about 50%. On behalf of the Fondazione Italiana Linfomi, a multicenter phase II study was designed to assess whether a combination of bendamustine, rituximab and bortezomib (BRB) (EudraCT Number:2013-005129-22) could be considered a promising new treatment in this setting. Patients and Methods This single-arm phase II study tested the hypothesis that 18-months PFS is at least 65%. The required sample size was 38 patients (alpha=0.10; beta=0.25; minimum follow up=24 months). Treatment plan provided: rituximab 375 mg/m2 intravenously on day 1 followed by intravenously bendamustine 90 mg/m2 on day 1 and 2 and subcutaneous bortezomib 1.3 mg/m2 on day 1, 8, 15 and 22, every 28 days for 6 months (6 cycles). MYD88 L265P and CXCR4 S338X mutations were tested by ddPCR in bone marrow (BM), plasma and peripheral blood (PB) samples, both at baseline (as mutational screening) and at the end of treatment (for minimal residual disease purposes, MRD). Results Median age was 66.8 years (8 patients were older than 75 years). Many patients had features of advanced disease such as cytopenia (anemia 71%, thrombocytopenia 20%), systemic symptoms (40%) and symptomatic splenomegaly (24%). Sixteen (42%) patients had at least one comorbidity, mostly cardiovascular disease (21%) or metabolic disorders (16%), such as diabetes mellitus. Thirty patients completed six cycles, 7 patients stopped therapy for toxicity and 1 for progressive disease. Overall response rate at the end of therapy was 82%, including 4 (11%) complete, 15 (39%) very good partial, 12 (32%) partial responses according to IWM response criteria. At 18, 24, and 30 months PFS was 84% (95% CI 68-92%), 81% (95%CI 65-91) and 79% (95%CI 62-89) respectively. At 18 months OS was 92% (95%CI 77-97%) and no deaths were observed between 18 and 30 months. Nineteen patients (50%) experienced grade ≥3 hematological toxicity, mainly thrombocytopenia, 12 patients (31.5%) developed grade ≥3 extra-hematological toxicity of which only one cutaneous toxicity related to bendamustine. Bortezomib-related nervous system disorders were observed in 6 patients (5 of grade 1-2 and 1 of grade 3), with no discontinuations. Mutational data were available for 21 patients: all patients scored MYD88 L265P in BM, 18/19 (95%) in plasma and only 18/21 (86%) in PB, prospectively confirming the risk of false negative results when only PB of rituximab pre-treated patients is analyzed. CXCR4 S338X was detected only in one patient at baseline. MRD negativization rates after treatment differed across investigated tissues: in detail, 5/17 (29%) in BM, 6/14 (43%) in plasma and 12/16 (75%) in PB. Overall, a good concordance was observed between BM and plasma (Cohen's kappa= 0.714), suggesting the possibility of avoiding BM aspiration for mutational screening and MRD analysis. Conclusion The final results of FIL BRB phase II trial showed that BRB regimen, used as second-line therapy, is an effective and well-tolerated salvage treatment for RR-WM patients. The deep anti-tumor activity of the novel combination is highlighted by an absolute increase of PFS rate in comparison to historical controls (30-months PFS of 79%), as well as by high rates of clinical response, with an ORR (CR+VGPR+PR) of 82% (95%CI 66-92). Moreover, MRD monitoring showed promising efficacy of BRB regimen in clearing the residual disease. Disclosures Benevolo: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Amgen: Speakers Bureau. Ferrero: Morphosys: Research Funding; Servier: Speakers Bureau; EUSA Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees; Clinigen: Membership on an entity's Board of Directors or advisory committees. Cavallo: ROCHE: Membership on an entity's Board of Directors or advisory committees; Servier: Speakers Bureau; Gilead: Speakers Bureau. Gaidano: Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astrazeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Musuraca: janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Varettoni: AstraZeneca: Membership on an entity's Board of Directors or advisory committees; beigene: Membership on an entity's Board of Directors or advisory committees; janssen: Membership on an entity's Board of Directors or advisory committees; roche: Membership on an entity's Board of Directors or advisory committees. Vitolo: Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Mutational Screening for Mitochondrial tRNA Mutations in 150 Children with High Myopia

Background: Myopia is a very common eye disease with an unknown etiology. Increasing evidence shows that mitochondrial dysfunction plays an active role in the pathogenesis and progression of this disease. Objectives: The purpose of this study was to analyze the relationship between mitochondrial tRNA (mt-tRNA) variants and high myopia (HM). Methods: The entire mt-tRNA genes of 150 children with HM, as well as 100 healthy subjects, were PCR-amplified and sequenced. To assess the pathogenicity, we used the phylogenetic conservation analysis and pathogenicity scoring system. Results: We identified six candidate pathogenic variants: tRNALeu (UUR) T3290C, tRNAIle A4317G, tRNAAla G5591A, tRNASer (UCN) T7501C, tRNAHis T12201C, and tRNAThr G15915A. However, these variants were not identified in controls. Further phylogenetic analysis revealed that these variants occurred at the positions, which were very evolutionarily conserved and may have structural-functional impacts on the tRNAs. Subsequently, these variants may lead to the impairment of mitochondrial translation and aggravated mitochondrial dysfunction, which play an active role in the phenotypic expression of HM. Conclusions: Our results suggested that variants in mt-tRNA genes were the risk factors for HM, which provided valuable information for the early detection and prevention of HM.

Significance of NPM1 Gene Mutations in AML

The aim of this literature review is to examine the significance of the nucleophosmin 1 (NPM1) gene in acute myeloid leukaemia (AML). This will include analysis of the structure and normal cellular function of NPM1, the type of mutations commonly witnessed in NPM1, and the mechanism by which this influences the development and progression of AML. The importance of NPM1 mutation on prognosis and the treatment options available to patients will also be reviewed along with current guidelines recommending the rapid return of NPM1 mutational screening results and the importance of employing a suitable laboratory assay to achieve this. Finally, future developments in the field including research into new therapies targeting NPM1 mutated AML are considered.

Genetic Screening Revealed Latent Keratoconus in Asymptomatic Individuals

PurposeTo adopt molecular screening in asymptomatic individuals at high risk of developing keratoconus as a combinative approach to prevent subclinical patients from post-refractive surgery progressive corneal ectasia.MethodsIn this study, 79 Chinese and nine Greek families with keratoconus were recruited, including 91 patients with clinically diagnosed keratoconus as well as their asymptomatic but assumptive high-risk first-degree relatives based on underlying genetic factor. Mutational screening of VSX1, TGFBI, and ZEB1 genes and full clinical assessment including Pentacam Scheimpflug tomography were carried out in these individuals.ResultsFive variants in VSX1 and TGFBI genes were identified in three Chinese families and one Greek family, and four of them were novel ones. Surprisingly, ultra-early corneal changes in Belin/Ambrosio Enhanced Ectasia Display of Pentacam corneal topography together with co-segregated variants were revealed in the relatives who had no self-reported symptoms.ConclusionsVariants of VSX1 and TGFBI genes identified in both the clinically diagnosed and subclinical patients may cause the keratoconus through an autosomal dominant inheritance pattern, with different variable expressivity. Combining genetic with Belin/AmbrosioEnhanced Ectasia Display can be used to identify patients with latent keratoconus. This study indicates that genetic testing may play an important supplementary role in re-classifying the disease manifestation and evaluating the preoperative examination of refractive surgery.

Genetics of Sirenomelia, the Mermaid Syndrome

Sirenomelia (SML) is a rare, almost universally fatal congenital malformation presenting pathognomically with fused lower extremities and absent or malformed perineum. The classic Sirenomelia sequence includes a uniform spectrum of caudal malformations, spinal defects, and a single umbilical artery. SML is postulated to be due to a genetic predisposition, unmasked by biochemical or environmental triggers. Primary developmental defects in the formation of caudal mesoderm or embryonic caudal vessels with resultant local tissue hypoperfusion are proposed hypotheses for its pathogenesis. SML occurs sporadically in humans, presumably due to a spontaneous mutation, and is speculated to have an autosomal dominant inheritance pattern. In mutant mice, specific defects in Cyp26a1 and Bmp 7 genes are demonstrated to produce offsprings with SML. Bmp 7 is a signaling protein, which belongs to the transforming growth factor-β (TGF β) superfamily. Tsg 1, a Bmp and chordin-binding protein, functions as an activator-inhibitor of Bmp signaling in the embryonic caudal region (ECR). Loss of Bmp7 genes combined with a complete loss or half-dose of Tsg 1 is demonstrated to produce an invariable SML phenotype. SML is also demonstrated to occur with increased Retinoic acid (RA) signaling in the ECR. The Cyp26a1 gene is involved in coding for an enzyme, which expresses in ECR and degrades RA. A specific defect in this gene leads to excess local RA concentration and SML generation with a reported 20% penetrance in mutant mice. However, the mutational screening of Cyp26a1 and Bmp 7genes has failed to confirm their involvement in mankind and the molecular defect and genetic inheritability of SML in humans remain undefined.

Retinoblastoma Mutational Screening in India: Opportunities and Challenges in Clinical Decisions and Genetic Counselling

Background: India accounts for 20% of the global retinoblastoma (RB) burden. Existing data is sparse on RB1 gene germline mutations and its influence on clinical decisions is minimally explored. Methods: Fifty children with RB underwent complete clinical examination and appropriate multidisciplinary management. Screening of germline RB1 gene mutations was performed through next-generation sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA) analysis. The mutation and non-mutation groups were compared for clinical parameters especially severity and recurrence. Results: Twenty-nine patients had bilateral RB (BLRB) and 21 had unilateral RB (ULRB). The genetic analysis revealed 20 RB1 variations in 29 probands (79%), inclusive of 3 novel mutations, previously reported 16 mutations and heterozygous whole gene deletions. The mutation detection rate (MDR) was 86.2% in BLRB and 19% in ULRB. Associations of disease recurrence (p=0.021), progression (p=0.000) and higher percentage of optic nerve invasion, subretinal seeds and high-risk pathological factors were observed in the mutation group. Clinical management was influenced by the presence of germline mutations, particularly while deciding on enucleation, frequency of periodic follow up and radiotherapy. Conclusions: We identified novel RB1 mutations and our mutation detection rate was at par with previous robust global studies. Genetic results influenced clinical management and we suggest that it should be an essential and integral component of RB-care in India.