Results of a multicentre UK-wide retrospective study evaluating the efficacy of pixantrone in relapsed, refractory diffuse large B cell lymphoma

Pixantrone in patients with relapsed/refractory diffuse large B-cell lymphoma: A real-life, retrospective, multicenter trial on behalf of the "RTL" (Regional Tuscan Lymphoma network)

INTRODUCTION

Pixantrone is a novel aza-anthracenedione with antineoplastic activity, currently approved for multiply relapsed/refractory diffuse large B-cell lymphoma (DLBCL), even if real-life data are limited.

METHODS

We investigated pixantrone efficacy and safety in clinical practice, as 3^rd or 4^th line therapy. We retrospectively analyzed a cohort of 37 R/R DLBCL patients managed in 8 Tuscan onco-hematological centers. Pixantrone, 50 mg/m² , was administered on days 1, 8, 15 of a 28 days cycle for up to 6 cycles. Response to therapy was evaluated according to the Lugano 2014 classification.

RESULTS

Pixantrone was administered as 3^rd or 4^th line in 24/37 (64.9%) and 13/37 (35.1%) cases. Overall response rate and CR rate were 43.2% and 32.4%. After a median follow-up of 6 months, 17/37 patients (46%) were alive, the main cause of death was progressive disease (14/37 cases, 37.9%). Median PFS was 3 months, median DOR was 17.9 months, and median OS was 9.7 months. A significant proportion of patients achieved a long-lasting response >12 months (8/37 cases). IPI>2 showed a trend toward inferior PFS.

CONCLUSION

In this real-life setting, pixantrone demonstrated appreciable efficacy in a population with poor prognosis; in a small proportion of cases, it can be associated with long-term remission.

Real-life experience with the combination of polatuzumab vedotin, rituximab, and bendamustine in aggressive B-cell lymphomas

Transplant-ineligible relapsed/refractory (rr) diffuse large B-cell lymphoma (DLBCL) patients represent an unmet medical need. Polatuzumab vedotin (Pola), an anti-CD79b antibody-drug-conjugate (ADG), with bendamustine- rituximab(BR) has recently gained approval for these patients, both in the USA and Europe, based on the GO29365 phase IIb trial. Real-life data with Pola are extremely limited. We report the outcomes of 61 Greek patients, who received Pola-(B)R mainly within a compassionate use program. Treatment was given for up to six 21-day cycles. Bendamustine was omitted in three cases due to previous short-lived responses. Fourty-nine rrDLBCL(efficacy cohort-EC) and 58 rr aggressive B-NHL (safety cohort-SC) patients received at least 1 Pola-BR cycle. Twenty-one (43%) patients of the EC responded with 12/49 (25%) CR and 9/49 (18%) PR as best response. Median progression-free survival, overall survival and duration of response were 4.0, 8.5, and 8.5 months respectively, while 55% of patients experienced a grade ≥3 adverse event, mainly hematologic. Treatment discontinuations and death during treatment were mainly due to disease progression. Twenty-two (41%) patients received further treatment; 11/22 are still alive, including one after CAR-T cells, and two after stem cell transplantation. Our data confirm that Pola-BR is a promising treatment for rrDLBCL patients, inducing an adequate response rate with acceptable toxicity. Pola-BR could be used as bridging therapy before further consolidative treatments.

Current Opinion on Pixantrone in the Treatment of Non-Hodgkin B-Cell Lymphoma

Not many treatment options exist for patients with relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) in whom first- and second-line therapies were unsuccessful. This is especially true for patients with aggressive lymphomas. The innovative agent pixantrone has shown some promising results in terms of disease-free and overall survival, both in monotherapy as well as in combinations. However, recent trials (Phase III and real-world studies) reported unsatisfactory results, thereby raising the question about the role of pixantrone in the current treatment of R/R aggressive lymphomas. Nonetheless, there might still be a potential position for this drug in combinations, for use as first-line treatment of patients with cardiac dysfunction. This article summarizes the definition, structure, mechanism of action and reduced cardiotoxicity of pixantrone as well as efficacy and toxicity both in monotherapy and in combinations, as treatment for aggressive and indolent non-Hodgkin lymphomas.

Effectiveness and Safety of Pixantrone for the Treatment of Relapsed or Refractory Diffuse Large B-Cell Lymphoma in Every-Day Clinical Practice: The Italian Cohort of the PIXA Registry

INTRODUCTION

Treatment of relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) represents a challenge for clinicians due to the lack of therapeutic options. DLBCL is not a rare disease in Italy. Pixantrone is an aza-anthracenedione, which, when compared to anthracyclines and anthracenediones, has a significantly reduced cardiotoxicity while maintaining good anti-tumor activity. However, the evidence on the use of pixantrone in the context of daily clinical practice is scarce.

METHODS

We focused on the Italian patient subset of a larger European retrospective study (the PIXA Registry) to assess the efficacy and safety of pixantrone in a real-life DLBCL population. The molecular profile of the disease and its impact on drug efficacy were also assessed.

RESULTS

Fifteen heavily pretreated DLBCL patients (13 males and 2 females) underwent treatment with pixantrone for a median of 2 cycles (range 1-6). Eight patients were bcl2 positive, 7 bcl6 positive, and 4 myc positive; 4 patients were diagnosed as double-hit, and 2 as triple-hit DLBCL. The overall response rate was 26.7% with a best response rate of 46.7%. Three patients had grade IV adverse events, which caused drug discontinuation. Four patients had 5 cases of grade III toxicities (1 thrombocytopenia, 1 stomatitis, and 3 neutropenia). One mild cardiac toxicity (sinus tachycardia for which no action was required) was possibly related to the study drug.

CONCLUSION

Our data documented drug efficacy that is satisfactory for this high-risk subset of patients with an acceptable toxicity profile. Results indicate that pixantrone could be a significant treatment option in patients with R/R aggressive DLBCL treated in everyday clinical practice.

Efficacy and safety of pixantrone for the treatment of multiply relapsed or refractory aggressive non-Hodgkin B-cell lymphomas

BACKGROUND AND OBJECTIVE

Few treatment options exist for patients with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) who fail first- and second-line therapies. Pixantrone is a novel aza-anthracenedione agent with reduced potential for cardiotoxicity but maintained anti-tumour activity relative to anthracyclines. The current retrospective, observational, real-life study was undertaken in 79 patients who received pixantrone monotherapy for multiply R/R aggressive B-cell NHL in Spain and Italy.

RESULTS

Before pixantrone, patients had received a median of 3 prior therapies and 84.6% of them were refractory to the last regimen. Median progression-free survival (mPFS) was 2.8 months (95% confidence interval [CI] 2.1-3.6) and median overall survival (mOS) was 4.0 months (95%CI 5.6-7.9), with an objective response rate (ORR) of 29% (complete remission [CR]: 13.2%, partial remission [PR]: 15.2%). Patients receiving ≥2 cycles of pixantrone showed mPFS and mOS of 3.1 and 6.0 months, respectively, and an ORR of 36.8% (CR: 17.5%, PR: 19.3%). Overall, 63.3% of patients reported ≥1 adverse event (AE), most commonly haematological AEs. One patient developed grade 2 sinus tachycardia.

CONCLUSION

Pixantrone was effective and well tolerated in a real-world population of multiply R/R patients with aggressive B-cell NHL, many of whom had very poor prognostic factors.

Limited efficacy of pixantrone in refractory diffuse large B-cell lymphoma

Relapsed or refractory diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with poor outcomes in patients ineligible for autologous stem cell transplantation. In this setting, novel treatment approaches are urgently required and the innovative agent pixantrone has shown some promising results in terms of disease-free and overall survival (OS). The present study retrospectively analyzed 12 patients routinely treated with pixantrone in monotherapy or in combinations at the Institute of Oncology Ljubljana, Slovenia, between January 2016 and October 2018. All 12 patients had refractory lymphoma to last treatment and a large proportion of them had other high risk features (high proliferation index, high disease stage, high international prognostic index (IPI) score, high percentage of primary refractory disease and high percentage of refractoriness to anthracyclines) at initiation of pixantrone. All patients progressed during treatment and none of the patients were alive at the time of analysis due to progressive lymphoma. Pixantrone specific median OS was 3.5 months (range, 0.5-10 months). A somewhat superior median OS (P=0.065) was observed in patients primarily sensitive to anthracyclines. Pixantrone has shown only limited efficacy in the present real world study comparable to the results of another real world UK retrospective analysis and substantially worse than the efficacy observed in the PIX301 registration trial. Therefore, an appropriate selection of patients for this treatment is crucial. Despite the limited experience due to a small number of patients, it was recommended to consider only patients with relapsed (and not refractory) disease, patients with non-primary refractory disease and those with fewer lines of prior therapy.

A new therapeutic approach in very refractory diffuse large B-cell lymphoma

PURPOSE

Patients with diagnosis of diffuse large B-cell lymphoma, who relapse after stem cell transplant (SCT) or are no candidates to SCT, have a poor prognosis and no current treatment is available. Thus, we conduct a rotatory chemotherapy schedule that employed low doses of chemotherapy agents to assess efficacy and toxicity in this setting of patients; the end point was the improved outcome.

METHODS

Retrospectively we revised an analysis of 461 patients who were treated with a low-doses regimen of cytotoxic agents, who were treated in a single institution, all patients has been treated with at least two salvage regimens, including SCT, > 18 years, performance status < 3, and that were informed about the possibility of severe toxicities,, were considered candidates to the study. They received a weekly rotatory scheme including low doses of cytotoxic agents during 2 years.

RESULTS

Overall response rate was achieved in 314 patients (68%, 95% Confidence interval (CI) 59-76%) and complete response was achieved in 151 cases (32%, 95% CI 25-38%); actuarial curves at 10 years show that progression-free survival was 58% (95% CI 51-66%) and OS was 50% (95% CI 43-57%). Dose reduction was not necessary; toxicity was minimal and well controlled. No death related to acute or late toxicities has been observed.

CONCLUSION

Low doses of cytotoxic agents for continuous, prolonged periods, with minimal drug-free intervals, represent a novel, active, and easily tolerated approach to management of patients with DLBCL in a terminal phase and improved outcome.

Pixantrone: A Review in Relapsed or Refractory Aggressive Non-Hodgkin's Lymphoma

Pixantrone (Pixuvri^®) is an aza-anthracenedione with a novel mode of action that is conditionally approved in the EU for use as monotherapy in adult patients with multiply relapsed or refractory aggressive B-cell non-Hodgkin's lymphoma (NHL). In the randomized, open-label, multinational, phase 3 PIX301 trial in patients with multiply relapsed or refractory aggressive NHL, the complete response (CR) plus unconfirmed CR (uCR) rate at the end of treatment (primary endpoint) was significantly higher with intravenous pixantrone monotherapy than with a single-agent comparator (vinorelbine, oxaliplatin, ifosfamide, etoposide, mitoxantrone or gemcitabine). Post hoc analysis also demonstrated a significantly higher CR/uCR rate in the subgroup of patients with centrally confirmed aggressive B-cell NHL who were receiving pixantrone versus a comparator agent as third- or fourth-line therapy. Pixantrone was generally well tolerated in PIX301, with a manageable adverse event profile. In conclusion, pixantrone is a useful option in patients with multiply relapsed or refractory aggressive B-cell NHL. Further results examining the use of pixantrone in combination with rituximab in patients previously treated with rituximab-containing regimens are awaited with interest.

Diffuse large B-cell lymphoma: R-CHOP failure-what to do?

Although rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is the standard treatment for patients with diffuse large B-cell lymphoma (DLBCL), ∼30% to 50% of patients are not cured by this treatment, depending on disease stage or prognostic index. Among patients for whom R-CHOP therapy fails, 20% suffer from primary refractory disease (progress during or right after treatment) whereas 30% relapse after achieving complete remission (CR). Currently, there is no good definition enabling us to identify these 2 groups upon diagnosis. Most of the refractory patients exhibit double-hit lymphoma (MYC-BCL2 rearrangement) or double-protein-expression lymphoma (MYC-BCL2 hyperexpression) which have a more aggressive clinical picture. New strategies are currently being explored to obtain better CR rates and fewer relapses. Although young relapsing patients are treated with high-dose therapy followed by autologous transplant, there is an unmet need for better salvage regimens in this setting. To prevent relapse, maintenance therapy with immunomodulatory agents such as lenalidomide is currently undergoing investigation. New drugs will most likely be introduced over the next few years and will probably be different for relapsing and refractory patients.

Rethinking Drugs from Chemistry to Therapeutic Opportunities: Pixantrone beyond Anthracyclines

Pixantrone (6,9-bis[(2-aminoethyl)amino]benzo[g]isoquinoline-5,10-dione) has been approved by the European Medicines Agency for the treatment of refractory or relapsed non-Hodgkin's lymphoma (NHL). It is popularly referred to as a novel aza-anthracenedione, and as such it is grouped with anthracycline-like drugs. Preclinical development of pixantrone was in fact tailored to retain the same antitumor activity as that of anthracyclines or other anthracenediones while also avoiding cardiotoxicity that dose-limits clinical use of anthracycline-like drugs. Preliminary data in laboratory animals showed that pixantrone was active, primarily in hematologic malignancies, but caused significantly less cardiotoxicity than doxorubicin or mitoxantrone. Pixantrone was cardiac tolerable also in animals pretreated with doxorubicin, which anticipated a therapeutic niche for pixantrone to treat patients with a history of prior exposure to anthracyclines. This is the case for patients with refractory/relapsed NHL. Pixantrone clinical development, regulatory approval, and penetration in clinical practice were nonetheless laborious if not similar to a rocky road. Structural and nominal similarities with mitoxantrone and anthracyclines may have caused a negative influence, possibly leading to a general perception that pixantrone is a "me-too" anthracycline. Recent insights suggest this is not the case. Pixantrone shows pharmacological and toxicological mechanisms of action that are difficult to reconcile with anthracycline-like drugs. Pixantrone is a new drug with its own characteristics. For example, pixantrone causes mis-segregation of genomic material in cancer cells and inhibits formation of toxic anthracycline metabolites in cardiac cells. Understanding the differences between pixantrone and anthracyclines or mitoxantrone may help one to appreciate how it worked in the phase 3 study that led to its approval in Europe and how it might work in many more patients in everyday clinical practice, were it properly perceived as a drug with its own characteristics and therapeutic potential. The road is rocky but not a dead-end.