Ofatumumab with iphosphamide, etoposide and cytarabine for patients with transplantation-ineligible relapsed and refractory diffuse large B-cell lymphoma.

The efficacy of salvage treatment of diffuse large B-cell lymphoma (DLBCL) patients who relapse or progress (rrDLBCL) after initial therapy is limited. Efficacy and safety of ofatumumab with iphosphamide, etoposide and cytarabine (O-IVAC) was evaluated in a single-arm study. Dosing was modified for elderly patients. Patients received up to six cycles of treatment. The primary end-point was the overall response rate (ORR). Patients were evaluated every two cycles and then six and 12 months after treatment. Other end-points included progression-free survival (PFS), event-free survival (EFS), overall survival (OS) and safety. Seventy-seven patients received salvage treatment with O-IVAC. The average age was 56.8 years; 39% had an Eastern Cooperative Oncology Group (ECOG) performance status of at least 3; 78% had disease of Ann Arbor stage 3 or 4; 58% received one or more prior salvage therapies. The ORR for O-IVAC was 54.5%. The median duration of study follow-up was 70 months. The median PFS and EFS were 16.3 months each. The median OS was 22.7 months. Age, ECOG performance status and the number of prior therapy lines were independent predictors of survival. Treatment-related mortality was 15.5%. O-IVAC showed a high response rate in a difficult-to-treat population and is an attractive treatment to bridge to potentially curative therapies.

High efficacy of BGD (bendamustine, gemcitabine, and dexamethasone) in relapsed/refractory Hodgkin Lymphoma.

The optimal salvage therapy in relapsed/refractory Hodgkin lymphoma (R/R HL) has not been defined so far. The goal of this multicenter retrospective study was to evaluate efficacy and safety of BGD (bendamustine, gemcitabine, dexamethasone) as a second or subsequent line of therapy in classical R/R HL. We have evaluated 92 consecutive R/R HL patients treated with BGD. Median age was 34.5 (19-82) years. Fifty-eight patients (63%) had received 2 or more lines of chemotherapy, 32 patients (34.8%) radiotherapy, and 21 patients (22.8%) an autologous hematopoietic stem cell transplantation (autoHCT). Forty-four patients (47.8%) were resistant to first line of chemotherapy. BGD therapy consisted of bendamustine 90 mg/m2 on days 1 and 2, gemcitabine 800 mg/m2 on days 1 and 4, dexamethasone 40 mg on days 1-4. Median number of BGD cycles was 4 (2-7). The following adverse events ≥ 3 grade were noted: neutropenia (22.8%), thrombocytopenia (20.7%), anemia (15.2%), infections (10.9%), AST/ALT increase (2.2%), and skin rush (1.1%). After BGD therapy, 51 (55.4%) patients achieved complete remission, 23 (25%)-partial response, 7 (7.6%)-stable disease, and 11 (12%) patients experienced progression disease. AutoHCT was conducted in 42 (45.7%) patients after BGD therapy, and allogeneic HCT (alloHCT) in 16 (17.4%) patients. Median progression-free survival was 21 months. BGD is a highly effective, well-tolerated salvage regimen for patients with R/R HL, providing an excellent bridge to auto- or alloHCT.

Mutations resulting in the formation of hyperactive complement convertases support cytocidal effect of anti-CD20 immunotherapeutics.

Anti-CD20 monoclonal antibodies (mAbs) rituximab and ofatumumab are potent activators of the classical complement pathway, and have been approved for the treatment of B-cell malignancies. However, complement exhaustion and overexpression of complement inhibitors by cancer cells diminish their therapeutic potential. The strategies of targeting membrane complement inhibitors by function-blocking antibodies and the supplementation with fresh frozen plasma have been proposed to overcome tumour cell resistance. We present a novel approach, which utilizes gain-of-function variants of complement factor B (FB), a component of alternative C3/C5 convertases, which augment mAb-activated reactions through a positive feedback mechanism called an amplification loop. If complement concentration is limited, an addition of quadruple gain-of-function FB mutant p.D279G p.F286L p.K323E p.Y363A (or selected single mutants) results in significantly increased complement-mediated lysis of ofatumumab-resistant tumour cells, as well as the complete lysis of moderately sensitive cells. Importantly, this effect cannot be achieved by further increasing ofatumumab concentration. Potentiation of cytotoxic effect towards moderately sensitive cells was less apparent at physiological serum concentration. However, an addition of hyperactive FB could compensate the loss of cytotoxic potential of serum collected from the NHL and CLL patients after infusion of rituximab. Residual levels of rituximab in such sera, in combination with added FB, were able to efficiently lyse tumour cells. We suggest that the administration of gain-of-function variants of FB can restore cytotoxic potential of complement-exhausted serum and maximize the therapeutic effect of circulating anti-CD20 mAbs.

Stem cell mobilization in patients with dialysis-dependent multiple myeloma: Report of the Polish Myeloma Study Group.

INTRODUCTION: High-dose chemotherapy with autologous hematopoietic stem cell transplantation (auto-HSCT) improves the outcome of patients with multiple myeloma (MM). It seems that auto-HSCT is also a feasible therapeutic option in MM dialysis-dependent (MMDD) patients. However, to perform transplantation, a sufficient number of stem cells must be collected. MATERIALS AND METHODS: Given that data on mobilization of auto-HSC efficacy and safety in dialysis-dependent patients are limited, we report data from all Polish Centers belonging to the Polish Myeloma Study Group. Twenty-eight dialysis-dependent MM-patients were enrolled into this retrospective analysis. The study population comprised patients diagnosed between 2004 and 2015 in whom an attempt to collect auto-HSC was made (68%: women, median age: 56). Patients received granulocyte-colony stimulating factor (G-CSF) alone or in combination with chemotherapy and autologous peripheral blood stem cells (auto-PBSCs) were collected by leukapheresis. RESULTS AND CONCLUSIONS: The success rate in terms of obtaining sufficient number of CD34(+) cells/kg for an auto-HSCT (≥2 × 106 cells/kg body weight) during the first mobilization attempt was 92% (26/28 patients), and for 2 auto-HSCTs (≥4 × 106 cells/kg) - was 75% (21/28 patients). After the second mobilization attempt (undertaken in 8 patients), a sufficient number of CD34(+)/kg cells for an auto-HSCT was obtained for all patients and the number of CD34(+)/kg collected cells was sufficient for 2 auto-HSCT in 6 additional patients. Hematologic toxicity and infections were the most frequent complications. Higher doses of cytarabine (>1.6 g/m2 ) and cyclophosphamide (> 2 g/m2 ) should be avoided in MMDD patients due to toxicity. Further studies are needed to establish mobilization regimens, confirm their safety, and dosing in MMDD patients.

Parsaclisib, a PI3Kδ inhibitor, in relapsed and refractory mantle cell lymphoma (CITADEL-205): a phase 2 study.

Background: Parsaclisib is a potent and highly selective PI3Kδ inhibitor that has shown clinical benefit in patients with relapsed/refractory (R/R) B-cell malignancies. In this phase 2 study (CITADEL-205; NCT03235544, EudraCT 2017-003148-19), the efficacy and safety of parsaclisib was evaluated in patients with R/R mantle cell lymphoma (MCL). Methods: Patients ≥18 years old with pathologically confirmed R/R MCL and prior treatment with 1-3 systemic therapies, with (cohort 1) or without (cohort 2) previous Bruton kinase inhibitor (BTKi) treatment, received oral parsaclisib 20 mg once-daily (QD) for 8 weeks, then either parsaclisib 20 mg once-weekly (weekly dosing group [WG]) or parsaclisib 2.5 mg QD (daily dosing group [DG]). The primary endpoint was objective response rate (ORR). Findings: At the primary analysis data cutoff on January 15, 2021, 53 patients in cohort 1 (BTKi-experienced) (WG, n = 12; DG: n = 41) and 108 patients in cohort 2 (BTKi-naive) (WG, n = 31; DG: n = 77) had received parsaclisib monotherapy. The BTKi-experienced cohort was closed after an interim analysis demonstrated limited clinical benefit. In the BTKi-naive cohort, the ORR (95% CI) for DG (dosing selected for further study) was 70.1% (58.6%-80.0%), with a complete response rate (95% CI) of 15.6% (8.3%-25.6%) and a median duration of response (95% CI) of 12.1 (9.0-not evaluable) months. Treatment-emergent adverse events (TEAEs) occurred among 90.7% (98/108) of all treated patients in the BTKi-naive cohort. Grade ≥3 TEAEs occurred among 62.0% (67/108) of patients, including diarrhoea (13.9%, 15/108) and neutropenia (8.3%, 9/108). Parsaclisib interruption, reduction, or discontinuation due to TEAEs occurred among 47.2% (51/108), 8.3% (9/108), and 25.0% (27/108) of patients, respectively. Fatal TEAEs were experienced by six patients and determined to be treatment-related in one patient. Interpretation: Parsaclisib, a potent, highly selective, PI3Kδ inhibitor demonstrated meaningful clinical benefits and a manageable safety profile (25.0% discontinuation rate, low incidences of individually reported grade ≥3 or serious adverse events) in R/R MCL patients with no prior BTKi therapy. Limited clinical benefit was observed with parsaclisib monotherapy in patients who had previously received BTKi treatment. Future development of PI3K inhibitors for NHL will require further investigation of dose optimisation to improve safety and long-term survival. Funding: Incyte Corporation.

In Silico Designed Gain-of-Function Variants of Complement C2 Support Cytocidal Activity of Anticancer Monoclonal Antibodies.

The molecular target for the classical complement pathway (CP) is defined by surface-bound immunoglobulins. Therefore, numerous anticancer monoclonal antibodies (mAbs) exploit the CP as their effector mechanism. Conversely, the alternative complement pathway (AP) is spontaneously induced on the host and microbial surfaces, but complement inhibitors on host cells prevent its downstream processing. Gain-of-function (GoF) mutations in the AP components that oppose physiological regulation directly predispose carriers to autoimmune/inflammatory diseases. Based on the homology between AP and CP components, we modified the CP component C2 so that it emulates the known pathogenic mutations in the AP component, factor B. By using tumor cell lines and patient-derived leukemic cells along with a set of clinically approved immunotherapeutics, we showed that the supplementation of serum with recombinant GoF C2 variants not only enhances the cytocidal effect of type I anti-CD20 mAbs rituximab and ofatumumab, but also lowers the threshold of mAbs necessary for the efficient lysis of tumor cells and efficiently exploits the leftovers of the drug accumulated in patients' sera after the previous infusion. Moreover, we demonstrate that GoF C2 acts in concert with other therapeutic mAbs, such as type II anti-CD20, anti-CD22, and anti-CD38 specimens, for overcoming cancer cells resistance to complement attack.

Genetically determined telomere length and multiple myeloma risk and outcome.

Telomeres are involved in processes like cellular growth, chromosomal stability, and proper segregation to daughter cells. Telomere length measured in leukocytes (LTL) has been investigated in different cancer types, including multiple myeloma (MM). However, LTL measurement is prone to heterogeneity due to sample handling and study design (retrospective vs. prospective). LTL is genetically determined; genome-wide association studies identified 11 SNPs that, combined in a score, can be used as a genetic instrument to measure LTL and evaluate its association with MM risk. This approach has been already successfully attempted in various cancer types but never in MM. We tested the "teloscore" in 2407 MM patients and 1741 controls from the International Multiple Myeloma rESEarch (IMMeNSE) consortium. We observed an increased risk for longer genetically determined telomere length (gdTL) (OR = 1.69; 95% CI 1.36-2.11; P = 2.97 × 10-6 for highest vs. lowest quintile of the score). Furthermore, in a subset of 1376 MM patients we tested the relationship between the teloscore and MM patients survival, observing a better prognosis for longer gdTL compared with shorter gdTL (HR = 0.93; 95% CI 0.86-0.99; P = 0.049). In conclusion, we report convincing evidence that longer gdTL is a risk marker for MM risk, and that it is potentially involved in increasing MM survival.

Monitoring of the Complement System Status in Patients With B-Cell Malignancies Treated With Rituximab.

Rituximab is a pioneering anti-CD20 monoclonal antibody that became the first-line drug used in immunotherapy of B-cell malignancies over the last twenty years. Rituximab activates the complement system in vitro, but there is an ongoing debate on the exact role of this effector mechanism in therapeutic effect. Results of both in vitro and in vivo studies are model-dependent and preclude clear clinical conclusions. Additional confounding factors like complement inhibition by tumor cells, loss of target antigen and complement depletion due to excessively applied immunotherapeutics, intrapersonal variability in the concentration of main complement components and differences in tumor burden all suggest that a personalized approach is the best strategy for optimization of rituximab dosage and therapeutic schedule. Herein we critically review the existing knowledge in support of such concept and present original data on markers of complement activation, complement consumption, and rituximab accumulation in plasma of patients with chronic lymphocytic leukemia (CLL) and non-Hodgkin's lymphomas (NHL). The increase of markers such as C4d and terminal complement complex (TCC) suggest the strongest complement activation after the first administration of rituximab, but not indicative of clinical outcome in patients receiving rituximab in combination with chemotherapy. Both ELISA and complement-dependent cytotoxicity (CDC) functional assay showed that a substantial number of patients accumulate rituximab to the extent that consecutive infusions do not improve the cytotoxic capacity of their sera. Our data suggest that individual assessment of CDC activity and rituximab concentration in plasma may support clinicians' decisions on further drug infusions, or instead prescribing a therapy with anti-CD20 antibodies like obinutuzumab that more efficiently activate effector mechanisms other than complement.

Dual-point FDG-PET/CT for treatment response assessment in Hodgkin lymphoma, when an FDG-avid lesion persists after treatment.

FDG-PET/CT (PET) is now considered the standard imaging tool for Hodgkin Lymphoma (HL) staging and restaging. However a CT-detected residual mass at the end of therapy (EoT) is still a challenge for PET interpretation. The aim of our study was to improve the overall accuracy of EoT PET/CT by using a dynamic dual-point scanning at 60 and 120 after FDG injection (2P-PET/CT). Fifty-one HL patients showing a single residual FDG-avid mass (SFAM) at EoT PET/CT were included in the study in Italy and Poland. Treatment was ABVD, ABVD followed by BEACOPP or ABVD plus radiotherapy. Only patients with a SFAM and a Deauville score (DS) > 2 in EoT PET/CT were included in the study. Two independent nuclear medicine reviewed images with a semi-quantitative analysis (SUVMax and retention index, RI) and a visual scoring according to DS. Compared to standard PET, 2P-PET/CT showed only a modest increase in NPV and PPV, from 0.87 to 0.89 and of the PPV from 0.67 to 0.71, respectively. Increase of the overall accuracy became substantial upon including in the analysis only patients whose images were acquired in strict adhesion to original protocol of 2P-PET/CT scanning: (t 120'-6040 min): the sensitivity increased from 0.60 to 1.00, PPV from 0.75 to 0.83 and NPV from 0.89 to 1. This study, with caution for the small number of patients included, seems to suggest that 2P-PET/CT could increase the overall accuracy of EoT PET/CT in correctly classifying treatment response in HL with a persisting SFAM at EoT.

Pixantrone, etoposide, bendamustine, rituximab (P[R]EBEN) as an effective salvage regimen for relapsed/refractory aggressive non-Hodgkin lymphoma-Polish Lymphoma Research Group real-life analysis.

BACKGROUND: Despite a significant improvement in treatment outcomes, 30-40% of aggressive non-Hodgkin lymphomas (NHL) patients are refractory or relapse after the first line therapy. Half of them are not eligible to autologous stem cell transplantation (ASCT) due to failure of platinum-based salvage regimens. Pixantrone is conditionally approved in Europe in patients with R/R aggressive NHL failing at least 2 previous lines of therapy. Polish Lymphoma Research Group (PLRG) evaluated the efficacy and tolerability of P[R]EBEN combining pixantrone, etoposide, bendamustine with or without rituximab), a new regimen developed recently by Francesco d'Amore, in real-life experience. METHODS: In this retrospective audit, we analyzed the data of consecutive 25 R/R NHL cases, treated with P[R]EBEN regimen in 9 PLRG centers. Safety and efficacy data, including adverse reactions (AE), response rates, progression-free and overall survival (PFS and OS) were collected. RESULTS: Overall response rate (ORR) to P[R]EBEN regimen was 68% (40% CR and 28% PR). Most patients responded, relatively early, by second cycle of therapy. P[R]EBEN was effective in 8 out of 15 patients (53%) refractory to previous platinum-based salvage regimens. In 4 patients (16%) stabilization of disease (SD) during therapy was observed and further 4 patients (16%) progressed during the treatment (PD). Response rates were higher in patients, chemosensitive to their prior regimen (ORR - 87.5%, including 50% CR). At the median follow-up of 7.5 months (range 1-16) the median PFS and OS were not reached. Projected PFS and OS at 12 months are 68% and 78% respectively. The P[R]EBEN regimen was well tolerated and most of patients received it as out-patients. AEs grade ≥3 occurred in 17 patients (68%). Most common grade 3-4 AEs were due to hematological toxicity with febrile neutropenia observed in 5 patients (20%). There were no episodes of septic deaths. Six patients (24%) died during treatment and follow-up period, all of them due to lymphoma progression. CONCLUSION: Our data suggest good efficiency and tolerability of P[R]EBEN regimen as a rescue therapy in patients with R/R aggressive NHL.