Combination of the MEK inhibitor pimasertib with BTK or PI3K-delta inhibitors is active in preclinical models of aggressive lymphomas

BACKGROUND

Lymphomas are among the most common human cancers and represent the cause of death for still too many patients. The B-cell receptor with its downstream signaling pathways represents an important therapeutic target for B-cell lymphomas. Here, we evaluated the activity of the MEK1/2 inhibitor pimasertib as single agent and in combination with other targeted drugs in lymphoma preclinical models.

MATERIALS AND METHODS

Cell lines derived mature B-cell lymphomas were exposed to increasing doses of pimasertib alone. Immunoblotting and gene expression profiling were performed. Combination of pimasertib with idelalisib or ibrutinib was assessed.

RESULTS

Pimasertib as single agent exerted a dose-dependent antitumor activity across a panel of 23 lymphoma cell lines, although at concentrations higher than reported for solid tumors. Strong synergism was observed with pimasertib combined with the PI3K inhibitor idelalisib and the BTK inhibitor ibrutinib in cell lines derived from diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma. The data were confirmed in an in vivo experiment treating DLBCL xenografts with pimasertib and ibrutinib.

CONCLUSION

The data presented here provide the basis for further investigation of regimens including pimasertib in relapsed and refractory lymphomas.

Large genomic aberrations detected by SNP array are independent prognosticators of a shorter time to first treatment in chronic lymphocytic leukemia patients with normal FISH

BACKGROUND

Genomic complexity can predict the clinical course of patients affected by chronic lymphocytic leukemia (CLL) with a normal FISH. However, large studies are still lacking. Here, we analyzed a large series of CLL patients and also carried out the so far largest comparison of FISH versus single-nucleotide polymorphism (SNP) array in this disease.

PATIENTS AND METHODS

SNP-array data were derived from a previously reported dataset.

RESULTS

Seventy-seven of 329 CLL patients (23%) presented with a normal FISH. At least one large (>5 Mb) genomic aberration was detected by SNP array in 17 of 77 patients (22%); this finding significantly affected TTT. There was no correlation with the presence of TP53 mutations. In multivariate analysis, including age, Binet stage, IGHV genes mutational status and large genomic lesion, the latter three factors emerged as independent prognosticators. The concordance between FISH and SNP array varied between 84 and 97%, depending on the specific genomic locus investigated.

CONCLUSIONS

SNP array detected additional large genomic aberrations not covered by the standard FISH panel predicting the outcome of CLL patients.

Clinical and molecular characterization of diffuse large B-cell lymphomas with 13q14.3 deletion

BACKGROUND

Deletions at 13q14.3 are common in chronic lymphocytic leukemia and are also present in diffuse large B-cell lymphomas (DLBCL) but never in immunodeficiency-related DLBCL. To characterize DLBCL with 13q14.3 deletions, we combined genome-wide DNA profiling, gene expression and clinical data in a large DLBCL series treated with rituximab, cyclophosphamide, doxorubicine, vincristine and prednisone repeated every 21 days (R-CHOP21).

PATIENTS AND METHODS

Affymetrix GeneChip Human Mapping 250K NspI and U133 plus 2.0 gene were used. MicroRNA (miRNA) expression was studied were by real-time PCR. Median follow-up of patients was 4.9 years.

RESULTS

Deletions at 13q14.3, comprising DLEU2/MIR15A/MIR16, occurred in 22/166 (13%) cases. The deletion was wider, including also RB1, in 19/22 cases. Samples with del(13q14.3) had concomitant specific aberrations. No reduced MIR15A/MIR16 expression was observed, but 172 transcripts were significantly differential expressed. Among the deregulated genes, there were RB1 and FAS, both commonly deleted at genomic level. No differences in outcome were observed in patients treated with R-CHOP21.

CONCLUSIONS

Cases with 13q14.3 deletions appear as group of DLBCL characterized by common genetic and biologic features. Deletions at 13q14.3 might contribute to DLBCL pathogenesis by two mechanisms: deregulating the cell cycle control mainly due RB1 loss and contributing to immune escape, due to FAS down-regulation.

Analysis of the host pharmacogenetic background for prediction of outcome and toxicity in diffuse large B-cell lymphoma treated with R-CHOP21

Knowledge on the impact of pharmacogenetics in predicting outcome and toxicity in diffuse large B-cell lymphoma (DLBCL) is scant. We tested 106 consecutive DLBCL treated with R-CHOP21 for 19 single nucleotide polymorphisms (SNPs) from 15 genes potentially relevant to rituximab-CHOP (R-CHOP) pharmacogenetics. Associations of SNPs with event-free survival (EFS) and toxicity were controlled for multiple testing. Genotypic variants of nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase p22phox (CYBA rs4673) and alpha1 class glutathione S-transferase (GSTA1 rs3957357) were independent predictors of EFS (CYBA rs4673 TT genotype: HR 2.06, P=0.038; GSTA1 rs3957357 CT/TT genotypes: HR 0.38, P=0.003), after adjusting for International Prognostic Index (IPI). CYBA rs4673 and GSTA1 rs3957357 also predicted outcome in DLBCL subgroups by IPI. Impact of SNPs on toxicity was evaluated in 658 R-CHOP21 courses utilizing generalized estimating equations. NCF4 rs1883112 was an independent predictor against hematologic (odds ratios (OR): 0.45; P=0.018), infectious (OR: 0.46; P=0.003) and cardiac toxicity (OR: 0.37; P=0.023). Overall, host SNPs affecting doxorubicin pharmacodynamics (CYBA rs4673) and alkylator detoxification (GSTA1 rs3957357) may predict outcome in R-CHOP21-treated DLBCL. Also, NCF4 rs1883112, a SNP of NAD(P)H oxidase p40phox, may have a function in protecting against hematologic and nonhematologic toxicity. These results highlight the need to improve characterization of the host genetic background for a better prognostication of DLBCL.

Sensory and cognitive evoked potentials in a case of congenital hydrocephalus

We studied auditory and visual evoked potentials in D.W., a patient with congenital stenosis of the cerebral aqueduct. Head CT scans revealed marked hydrocephalus with expanded ventricles filling more than 80% of the cranium and compressing brain tissue to less than 1 cm in thickness. Despite the striking neuroanatomical abnormalities, however, the patient functioned well in daily life and was attending a local community college at the time of testing. Evoked potentials provided evidence of preserved sensory processing at cortical levels. Pattern reversal visual evoked potentials had normal latencies and amplitudes. Brain-stem auditory evoked potentials (BAEPs) showed normal wave V latencies. Na and Pa components of middle-latency AEP had normal amplitudes and latencies at the vertex, although amplitudes at lateral electrodes were larger than at the midline. In contrast to the normal sensory responses, long-latency auditory evoked potentials to standard and target tones showed abnormal P3 components. Standard tones (probability 85%), evoked N1 components with normal amplitudes (-3.7 microV) and latencies (103 msec), but also elicited large P3 components (17 microV, latency 305 msec) that were never observed following frequent stimuli in control subjects. Target stimuli (probability 15%) elicited P3s in D.W. and controls, but P3 amplitudes were enhanced in D.W. (to more than 40 microV) and the P3 showed an unusual, frontal distribution. The results are consistent with a subcortical source of the P300. Moreover, they suggest that the substitution of controlled for automatic processes may help high-functioning hydrocephalics compensate for abnormalities in cerebral structure.