Sequential therapy of four cycles of bortezomib, melphalan, and prednisolone followed by continuous lenalidomide and dexamethasone for transplant-ineligible newly diagnosed multiple myeloma

Efficacy and safety analysis of bortezomib-based triplet regimens sequential lenalidomide in newly diagnosed multiple myeloma patients

The aim of this study is to analyze the efficacy and safety of sequential therapy with bortezomib-based triplet regimens without lenalidomide (PXD, including VTD, PAD, and VCD) followed by continuous lenalidomide and dexamethasone (Rd) or bortezomib and dexamethasone (Vd) treatment. The main objective is to evaluate the advantages of PXD followed by Rd compared to the combinations of bortezomib-lenalidomide-dexamethasone (VRd) in newly diagnosed multiple myeloma (NDMM). Fifty-eight nontransplant NDMM patients who were admitted to our department from 2017 to 2019 were included in this study. Bortezomib-based triplet regimens were initially selected and followed by Rd or Vd as continuous treatment once the patients achieved partial remission (PR) or better response. The efficacy and safety of the patients were observed. The Rd continuous treatment cohort was compared with historical data from the EVOLUTION trial on continuous VRd treatment. In our cohort, the overall survival rate was 100%, and progression-free survival (PFS) was 38.5% after a median of 19 (4-36) cycles of Rd continuous therapy was applied. During the follow-up period, the best outcome assessments achieved were 53.8% complete response (CR) and 84.6% excellent partial response (VGPR). A total of 23.1% had grade 3-4 or higher drug-related adverse reactions, mainly hematological toxicity, and no patients died of adverse reactions. Compared with the Vd group, the Rd group had a better PFS and VGPR rate (2-year PFS: 92.3% vs. 56.3%, P = 0.002; 3-year PFS: 69.2% vs. 8.0%, P < 0.001; VGPR: 84.6% vs. 69.2%, P = 0.02). No significant differences were found in ORR (100% vs. 92.3%) or CR (53.8% vs. 35.7%, P = 0.082). Compared with the EVOLUTION study, patients in the Rd group had a more advanced disease stage (stage III rate of 40% vs. 19%, P = 0.039) and worse physical status (KPS 50-60 rate of 25.0% vs. 2.0%, P = 0.000). However, a higher proportion of ORR (100% vs. 73.0%, P < 0.001), VGPR or better (75.0% vs. 32.0%, P < 0.001), and PFS at 12 months (90.0% vs. 68%, P = 0.011) were achieved. Sequential administration of bortezomib-based triplet regimens without lenalidomide as an initial therapy followed by Rd as a continuous treatment may not be inferior to VRd for first-line treatment in NDMM patients.

Melphalan induced germ cell toxicity and dose-dependent effects of β-aminoisobutyric acid in experimental rat model: Role of oxidative stress, inflammation and apoptosis

The success of chemotherapy regimens has led to an increase in cancer survival rate over the last decades. Melphalan has been widely used for the treatment of several types of cancers despite its gonadotoxic effects. Due to its ability to cause mutations in the spermatogonial stem cells and spermatids, melphalan can exert a negative impact on male reproductive health in young cancer survivors. β-aminoisobutyric acid (BAIBA), a myokine released by skeletal muscles, has been reported to have beneficial effects in diabetic nephropathy, cardiomyopathy and hepatic toxicity. However, the exact role of BAIBA in chemotherapy-induced germ cell toxicity is still unexplored. The present study aims to determine the dose-dependent (25, 50, and 100 mg/kg) effects of BAIBA on melphalan-induced (1.5 mg/kg) germ cell toxicity in sprague-dawley (SD) rats. The evaluation parameters included quantification of oxidative stress biomarkers, sperm count, sperm motility and head morphology, sperm and testicular DNA damage, sperm mitochondrial membrane potential, ultrastructural changes in sperms, histological and protein expression studies in testes. Melphalan treatment significantly altered all the above-mentioned parameters and the high dose (100 mg/kg) of BAIBA restored melphalan-induced toxicity in a significant manner by exerting antioxidant, anti-inflammatory and antiapoptotic effects. However, the medium dose (50 mg/kg) of BAIBA decreased the toxicity of melphalan and the low dose (25 mg/kg) of BAIBA failed to counteract the melphalan-induced male germ cell toxicity as well as the peripheral blood micronucleus induction. The antioxidant, anti-inflammatory and antiapoptotic role of BAIBA in melphalan-induced gonadal damage is a novel finding in an experimental rat model.

Juvenile exposure and adult risk assessment with single versus repeated exposure of melphalan in the germ cells of male SD rat: Deciphering the molecular mechanisms

Melphalan significantly contributes to the increase in childhood cancer survival rate. It acts as a gonadotoxic agent and leads to testes damage, dysbalance in gonadal hormones, and impairment in the germ cell proliferation. Therefore, it might be a potent threat to male fertility in individuals who have undergone melphalan treatment during childhood cancer. However, the molecular mechanisms of melphalan-induced gonadal damage are not yet fully explored and they need to be investigated to determine the benefit-risk profile. In the present study, juvenile male SD rats were subjected to single and intermittent cycles of melphalan exposure in a dose-dependent (0.375, 0.75 and 1.5 mg/kg) manner. Methods of end-points evaluations were quantification of micronuclei formation in peripheral blood, sperm count, sperm motility and head morphology, sperm and testicular DNA damage, histological studies in testes, oxidative/nitrosative stress parameters. A single cycle of exposure at high dose (1.5 mg/kg) produced significant effect on micronuclei formation only after the first week of exposure, whereas failed to produce significant effect at the end of the sixth week. Intermittent cycles of exposure at the dose of 1.5 mg/kg produced significant alterations in all the parameters (micronuclei in peripheral blood, testes and epididymides weight and length, MDA, GSH and nitrite levels, sperm count and motility, sperm head morphology, testicular and sperm DNA damage, protein expression in testes and histological parameters). So, time of exposure as well as the amount of exposure (total dosage administered) is critical in determining the magnitude of the damage in germ cell risk assessment.

Sirtuin 2 knockdown inhibits cell proliferation and RAS/ERK signaling, and promotes cell apoptosis and cell cycle arrest in multiple myeloma

The present study aimed to explore the regulatory role of sirtuin 2 (SIRT2) in malignant progression of multiple myeloma (MM) and the potential associated signaling pathways. In total, 30 patients with MM and 15 healthy bone marrow donors were enrolled in the current study and their bone marrow samples were collected to isolate the plasma cells. The expression levels of SIRT2 were detected in MM cell lines (KMS-28BM, U266, RPMI-8226 and NCI-H929) and normal plasma cells (collected from healthy bone marrow donors as the control) via reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis. SIRT2 knockdown was established by transfecting two MM cell lines (RPMI-8226 and NCI-H929 cells) with short hairpin RNA-SIRT2 recombinant plasmid; the control group was transfected with a control recombinant plasmid. Subsequently, the effect of SIRT2 knockdown on MM cell proliferation, apoptosis, cell cycle progression and RAS/ERK signaling was investigated via Cell Counting Kit-8, flow cytometry, RT-qPCR and western blot assays, respectively. The mRNA and protein expression levels of SIRT2 were increased in U266 (P<0.001), KMS-28BM (P<0.001), RPMI-8226 (P<0.001) and NCI-H929 (P<0.001) cells compared with those in the control cells. In NCI-H929 and RPMI-8226 cells, cell proliferation was decreased 48 h (P<0.05) and 72 h (P<0.05) after SIRT2 knockdown. Furthermore, the cell apoptotic rate was elevated 48 h after SIRT2 knockdown (P<0.01). In addition, the percentage of cells at the G₀/G₁ phase was increased (P<0.01), whereas the percentage of cells at the S phase was reduced (P<0.01) 48 h after SIRT2 knockdown. The expression levels of HRAS and phosphorylated-ERK were also reduced 48 h after SIRT2 knockdown. In conclusion, SIRT2 was highly expressed in MM cell lines, and knockdown of SIRT2 inhibited MM cell proliferation, inactivated the RAS/ERK signaling pathway, and promoted cell apoptosis and cell cycle arrest.

Prognostic impact of resistance to bortezomib and/or lenalidomide in carfilzomib-based therapies for relapsed/refractory multiple myeloma: The Kyoto Clinical Hematology Study Group, multicenter, pilot, prospective, observational study in Asian patients

Background

Combinatory strategies with carfilzomib (CFZ), a second‐generation proteasome inhibitor, plus dexamethasone (DEX) with or without lenalidomide (LEN) have shown promising efficacy for patients with relapsed/refractory multiple myeloma (RRMM) in pivotal clinical trials. However, their effects on patients who were resistance to bortezomib (BTZ) and/or LEN have not been fully evaluated in a daily practice setting.

Aims

To evaluate the real‐world efficacy and safety of CFZ‐based treatments; that is, CFZ with LEN plus DEX (KRD therapy) and CFZ with DEX (KD therapy), in Asian patients, we conducted a multicenter pilot prospective observational study in the Kyoto Clinical Hematology Study Group.

Methods and Results

All 50 patients with RRMM enrolled in this study were treated with CFZ‐based treatments between 2017 and 2019. KRD and KD were administered to 31 and 19 patients, respectively. The overall response rates (ORRs) were 80.6% with KRD and 73.7% with KD. Two‐year progression‐free survival (PFS) and overall survival (OS) were 58.5% and 79.7% with KRD, and 23.1% and 52.6% with KD. By multivariate analysis, refractoriness to BTZ and to LEN were identified as independent unfavorable factors for both PFS and OS. The common non‐hematologic AEs included hypertension (42.0%), fever (24.0%), fatigue (24.0%), and infection (16.0%). No serious heart failure was observed. This study is registered as UMIN000025108.

Conclusion

This study suggests the need of the development of novel CFZ‐containing strategy which can overcome the refractoriness to BTZ and/or LEN, while both KRD and KD were shown to be mostly feasible in Asian patients in a daily practice setting.