An update on emerging drugs for Hodgkin lymphoma

Role of HDACs in normal and malignant hematopoiesis

Normal hematopoiesis requires the accurate orchestration of lineage-specific patterns of gene expression at each stage of development, and epigenetic regulators play a vital role. Disordered epigenetic regulation has emerged as a key mechanism contributing to hematological malignancies. Histone deacetylases (HDACs) are a series of key transcriptional cofactors that regulate gene expression by deacetylation of lysine residues on histone and nonhistone proteins. In normal hematopoiesis, HDACs are widely involved in the development of various lineages. Their functions involve stemness maintenance, lineage commitment determination, cell differentiation and proliferation, etc. Deregulation of HDACs by abnormal expression or activity and oncogenic HDAC-containing transcriptional complexes are involved in hematological malignancies. Currently, HDAC family members are attractive targets for drug design, and a variety of HDAC-based combination strategies have been developed for the treatment of hematological malignancies. Drug resistance and limited therapeutic efficacy are key issues that hinder the clinical applications of HDAC inhibitors (HDACis). In this review, we summarize the current knowledge of how HDACs and HDAC-containing complexes function in normal hematopoiesis and highlight the etiology of HDACs in hematological malignancies. Moreover, the implication and drug resistance of HDACis are also discussed. This review presents an overview of the physiology and pathology of HDACs in the blood system.

Everolimus as a single agent in refractory or relapsed Hodgkin's lymphoma: the Brazilian Named Patient Program Experience

Background

Despite all the scientific progress that has been made on understanding the disease, prognosis for patients with relapsed and refractory Hodgkin's lymphoma remains poor and the treatment is palliative in the majority of the cases. Thus, the aim of this study was to present the results on the compassionate use of everolimus in a group of patients who were monitored at nine different centers in Brazil.

Methods

A 10-mg oral dose of everolimus was given to each patient daily. Response time was evaluated from the beginning of medication use until loss of response, toxicity or medical decision to cease treatment.

Results

Thirty-three patients were evaluated. The median age at the beginning of medication administration was 29 years. Patients had received a median of five prior therapies. Overall response rate was 45.4%, with 13 patients achieving partial response, two achieved clinical response, 14 remained with stable disease, two had disease progression, and two were not evaluated. Patients received a median of 14 cycles. Progression-free survival was nine months, and overall survival was estimated to be 36 months. Three patients used the medication for more than four years. The most frequently reported adverse events were thrombocytopenia and hypercholesterolemia. Three patients had pulmonary toxicity. Grade III and IV adverse events occurred in 39% of the patients.

Conclusion

Everolimus was found to provide a response in a group of patients with refractory or relapsed Hodgkin's lymphoma who had adequate tolerability to the drug.

Novel treatment concepts in Hodgkin lymphoma

Treatment of classical Hodgkin's lymphoma (HL) has been a success story, with cure of localized disease with radiotherapy in the 1930s, cure of advanced stages with combination chemotherapy with/without radiotherapy in the mid-1960s and continuous improvements since then. Nonetheless, at present approximately 2% of patients with classical HL are primarily refractory to conventional therapy with only 50% becoming long-term survivors. Another 13% of patients relapse, with only 60% being alive 10 years postrecurrence (as exemplified in this review in a Swedish cohort of 18- to 65-year-old patients diagnosed during the period 1992-2009). Recently, novel targeted drugs were approved for refractory/relapsed HL and here we review results of trials that form the basis for these approvals as well as new trials. In summary, brentuximab vedotin can be used in refractory patients (i) as a complement to high-dose chemotherapy with autologous stem cell transplantation (SCT) improving the chances of being able to proceed to an allogenic SCT and cure, (ii) as consolidation after autologous SCT and (iii) as palliative life-prolonging treatment. However, we have yet to determine whether this drug provides the greatest benefit in first- or second-line treatment, as consolidation or in refractory disease or relapse. Trials of immune checkpoint inhibitors, such as those targeting programmed death 1 (nivolumab and pembrolizumab), and thus not primarily the tumour cells, have shown overall response rates of >65%. Long-term results and data from Phase III trials are still lacking, but nivolumab recently gained approval in refractory patients already treated with brentuximab vedotin and autologous SCT. Other novel treatments of interest include T cells with a chimeric antigen receptor and combination therapies with histone deacetylase inhibitors.

Treatment of relapsed and refractory Hodgkin Lymphoma

Despite the high first-line cure rates in patients with Hodgkin Lymphoma (HL) still 10%-20% of patients suffer from relapsed or refractory disease. High-dose chemotherapy (HDCT) followed by autologous stem cell transplant (ASCT) is standard of care for suitable patients with relapsed or refractory HL and allows for cure in approximately 50%. Due to the poor prognosis of high-risk patients even with HDCT and ASCT, consolidation strategies have been evaluated to improve the cure rates. For patients with recurrence after HDCT and ASCT, treatment is palliative in most cases. The anti-CD30 antibody-drug conjugate brentuximab vedotin (BV) has been shown to induce high response rates in these patients; however, durable responses were reported in a small percentage of patients only. For carefully selected patients with multiple relapses, dose-reduced allogeneic transplant (RICallo) is a potentially curative option. The role of RICallo will have to be re-evaluated in the era of anti-programmed death-1 (PD1) antibodies.

Salvage treatment for relapsed/refractory Hodgkin lymphoma: role of allografting, brentuximab vedotin and newer agents

INTRODUCTION

Second-line, salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation (AUTO-SCT) is the standard of care for patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL). Approximately 50% of patients relapse after AUTO-SCT and their prognosis is generally poor. Brentuximab Vedotin (BV) has demonstrated efficacy in this setting and allogeneic (ALLO)-SCT represents an option with curative potential in this subgroup of patients.

AREAS COVERED

A systematic review has been conducted to explore the actual knowledge on ALLO-SCT, BV and newer agents in R/R HL.

EXPERT OPINION

The introduction of BV in clinical practice has significantly improved the management of post-AUTO-SCT relapses and the drug can induce durable remissions in a subset of R/R HL. Allografting select patients has been used to improve clinical outcomes and recent case series have begun to explore BV as a potential 'bridge' to allo-SCT, even though the optimal timing of ALLO-SCT after BV response remains undetermined. However, reduced tumor burden at the time of ALLO-SCT is a key factor to decrease relapse risk. Based on the unique composition of the tumor, more recently new agents such as PD-1 inhibitors have been developed. The potential role of PD-1 inhibitors with ALLO-SCT remains to be explored.

An Open-Label, Multicenter, Phase I/II Study of JNJ-40346527, a CSF-1R Inhibitor, in Patients with Relapsed or Refractory Hodgkin Lymphoma

PURPOSE

This phase I/II study investigated JNJ-40346527, a selective inhibitor of the colony-stimulating factor-1 receptor (CSF-1R) tyrosine kinase as treatment for relapsed or refractory classical Hodgkin lymphoma (cHL).

EXPERIMENTAL DESIGN

Patients ≥18 years with histopathologically confirmed initial diagnosis of cHL that had relapsed or was refractory after ≥1 appropriate therapies were assigned to sequential cohorts of oral daily doses of JNJ-40346527 (150, 300, 450, 600 mg every day, and 150 mg twice a day). For the dose-escalation phase, the primary endpoint was to establish the recommended phase II dose. Secondary endpoints included safety, pharmacokinetics, and pharmacodynamics.

RESULTS

Twenty-one patients [(150 mg: 3; 300 mg: 5; 450 mg: 3, 600 mg: 3) every day, and 150 mg twice a day: 7] were enrolled, 10 men, median age 40 (range, 19-75) years, median number of prior systemic therapies 6 (range, 3-14). No dose-limiting toxicities were observed; maximum-tolerated dose was not established. Best overall response was complete remission in 1 patient (duration, +352 days) and stable disease in 11 patients: (duration, 1.5-8 months). Median number of cycles: 4 (range, 1-16). Most common (≥20% patients) possibly drug-related adverse events (per investigator assessment) were nausea (n = 6), headache, and pyrexia (n = 5 each). JNJ-40346527 exposure increased in near dose-proportional manner over a dose range of 150 to 450 mg every day, but plateaued at 600 mg every day. Target engagement was confirmed (>80% inhibition of CSF-1R phosphorylation, 4 hours after dosing).

CONCLUSIONS

JNJ-40346527, a selective inhibitor of CSF-1R was well tolerated, and preliminary antitumor results suggested limited activity in monotherapy for the treatment of cHL.