Denileukin diftitox for the treatment of CD25 low-expression mycosis fungoides and Sézary syndrome

Advancements in the treatment of mycosis fungoides and Sézary syndrome: monoclonal antibodies, immunotherapies, and Janus kinase inhibitors

Mycosis fungoides (MF) and Sézary syndrome (SS) are forms of cutaneous T cell lymphoma (CTCL) that pose significant challenges in their clinical management, particularly in refractory and advanced-stage disease. With the emergence of novel therapeutic modalities however, there are increasing opportunities to exploit the current understanding of pathophysiologic mechanisms of MF/SS for treatment. This review summarizes recent advances in the treatment of MF/SS, with a focus on monoclonal antibodies, immunotherapies, and Janus kinase (JAK) inhibitors, including ongoing clinical trials.

Downregulation of CCKBR Expression Inhibits the Proliferation of Gastric Cancer Cells, Revealing a Potential Target for Immunotoxin Therapy

Background Increased CCKBR expression density or frequency has been reported in many neoplasms. Objective We aimed to investigate whether CCKBR drives the growth of gastric cancer (GC) and its potential as a therapeutic target of immunotoxins. Methods A lentiviral interference system was used to generate CCKBR-knockdown gastric cancer cells. Cell Counting Kit-8 and clonogenic assays were used to evaluate cell proliferation. Wound-healing and cell invasion assays were performed to evaluate cell mobility. Cell cycle was analyzed by flow cytometry. Tumor growth in vivo was investigated using a heterologous tumor transplantation model in nude mice. In addition, we generated the immunotoxin FQ17P and evaluated the combining capacity and tumor cytotoxicity of FQ17P in vitro. Results Stable downregulation of CCKBR expression resulted in reduced proliferation, migration and invasion of BGC-823 and SGC-7901 cells. The impact of CCKBR on gastric cancer cells was further verified through CCKBR overexpression studies. Downregulation of CCKBR expression also inhibited the growth of gastric tumors in vivo. Furthermore, FQ17P killed CCKBR-overexpressing GC cells by specifically binding to CCKBR on the tumor cell surface. Conclusion The CCKBR protein drives the growth, migration, and invasion of gastric cancer cells, and it might be a promising target for immunotoxin therapy based on its aberrant expression, functional binding interactions with gastrin, and subsequent internalization.

[Preclinical and clinical researches of Denileukin Diftitox (Genetical Recombination) (Remitoro®), a novel agent for T-cell lymphoma]

Denileukin Diftitox (DD) is a recombinant fusion protein of diphtheria toxin (DT) fragments and human interleukin-2 (IL-2). DD binds to IL-2 receptor (IL-2R) expressed on tumor cells and is taken up into the cells. Subsequently, DT fragments with adenosine diphosphate ribosylation enzyme inhibit protein synthesis, then ultimately trigger cell death. DD binds to both high- and intermediate-affinity IL-2Rs via IL-2 domain and inhibits growth of human T-cell lymphomas cell lines. E7777, which contains DD as an active component, has improved purity and an increased percentage of active monomer compared with the approved drug E7272 (ONTAK in the US, not approved in Japan). In the phase I clinical study in Japanese patients with relapsed or refractory peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL), the maximum tolerated dose and recommended dose of E7777 were 9 μg/kg/day (administered on Days 1-5 of each cycle) based on the evaluation of dose-limiting toxicity. In the phase II clinical study, the objective response rate was 36.1%, showing comparable efficacy to existing therapies. E7777 showed anti-tumor activity observed across the range of CD25 expression. Grade 3 or higher adverse events (AE) occurred in 94.6%, and serious AE such as capillary leak syndrome and rhabdomyolysis were reported. Therefore, safety monitoring activities have been continued along with alerting related events. Based on these results, E7777 obtained a new drug approval in Japan in March 2021 for the indication of relapsed or refractory PTCL/CTCL.

Camidanlumab tesirine in patients with relapsed or refractory lymphoma: a phase 1, open-label, multicentre, dose-escalation, dose-expansion study

BACKGROUND

Novel approaches are required to improve outcomes in relapsed or refractory classical Hodgkin lymphoma and non-Hodgkin lymphoma. We aimed to evaluate camidanlumab tesirine, an anti-CD25 antibody-drug conjugate, in this patient population.

METHODS

This was a phase 1, dose-escalation (part 1), dose-expansion (part 2), multicentre trial done in 12 hospital sites (seven in the USA and five in the UK). Adults (≥18 years old) with pathologically confirmed relapsed or refractory classical Hodgkin lymphoma or non-Hodgkin lymphoma, an Eastern Cooperative Oncology Group performance status 0-2, who had no therapies available to them with established clinical benefit for their disease stage were enrolled. Camidanlumab tesirine was administered intravenously (3-150 μg/kg) once every 3 weeks. Primary objectives were to assess dose-limiting toxicity, determine maximum tolerated dose and recommended expansion dose(s), and assess safety of camidanlumab tesirine. Safety was assessed in all treated patients; antitumour activity was assessed in patients with one or more valid baseline and post-baseline disease assessment and in those who had disease progression or died after first study-drug dose. This trial was registered with ClinicalTrials.gov, NCT02432235.

FINDINGS

Between Oct 5, 2015, and Jun 30, 2019, 133 patients were enrolled (77 [58%] had classical Hodgkin lymphoma and 56 (42%) had non-Hodgkin lymphoma). Median follow-up was 9·2 months (IQR 4·2-14·3). Eight dose-limiting toxicities were reported in five (6%) of 86 patients who were evaluable; the maximum tolerated dose was not reached. The recommended doses for expansion were 30 μg/kg and 45 μg/kg for patients with classical Hodgkin lymphoma and 80 μg/kg for patients with T-cell non-Hodgkin lymphomas. No recommended doses for expansion were defined for B-cell non-Hodgkin lymphomas. Grade 3 or worse treatment-emergent adverse events (reported by ≥10% of the 133 patients) included increased γ-glutamyltransferase (20 [15%] patients), maculopapular rash (16 [12%]), and anaemia (15 [11%]); 74 (56%) patients had serious treatment-emergent adverse events, most commonly pyrexia (16 [12%]). One (1%) fatal treatment-emergent adverse event and two (2%) deaths outside the reporting period were considered at least possibly study-drug related. Antitumoural activity was seen in classical Hodgkin and non-Hodgkin lymphomas; notably in all patients with classical Hodgkin lymphoma, the overall response was 71% (95% CI 60-81).

INTERPRETATION

These results warrant evaluation of camidanlumab tesirine as a potential treatment option for relapsed or refractory lymphoma, particularly in patients with classical Hodgkin lymphoma.

FUNDING

ADC Therapeutics.

Phase II study of E7777 in Japanese patients with relapsed/refractory peripheral and cutaneous T-cell lymphoma

E7777 is a recombinant cytotoxic fusion protein composed of the diphtheria toxin fragments A and B and human interleukin‐2. It shares an amino acid sequence with denileukin diftitox, but has improved purity and an increased percentage of active monomer. We undertook a multicenter, single‐arm phase II study of E7777 in patients with relapsed or refractory peripheral T‐cell lymphoma (PTCL) and cutaneous T‐cell lymphoma (CTCL) to evaluate its efficacy, safety, pharmacokinetics, and immunogenicity. A total of 37 patients were enrolled, of which 17 and 19 patients had PTCL and CTCL, respectively, and one patient with another type of lymphoma (extranodal natural killer/T‐cell lymphoma, nasal type), diagnosed by the Central Pathological Diagnosis Committee. Among the 36 patients with PTCL and CTCL, objective response rate based on the independent review was 36% (41% and 31%, respectively). The median progression‐free survival was 3.1 months (2.1 months in PTCL and 4.2 months in CTCL). The common adverse events (AEs) observed were increased aspartate aminotransferase (AST) / alanine aminotransferase (ALT), hypoalbuminemia, lymphopenia, and pyrexia. Our results indicated that a 9 µg/kg/d dose of E7777 shows efficacy and a manageable safety profile in Japanese patients with relapsed or refractory PTCL and CTCL, with clinical activity observed across the range of CD25 expression. The common AEs were manageable, but increase in ALT / AST, hypoalbuminemia, and capillary leak syndrome should be carefully managed during the treatment.

Novel therapies targeting cutaneous T cell lymphomas and their microenvironment

Cutaneous T-cell lymphomas (CTCL) are rare non-Hodgkin lymphomas with a generally indolent course managed with topical, skin-directed therapies. A small subset, however, will progress to advanced stage disease necessitating systemic therapy for disease control. Currently approved therapies have low response rates and generally short durations of response. Novel therapies, therefore, are urgently needed to address this unmet need. In this review, the mechanisms of CTCL pathogenesis and progression, including the role of the tumor microenvironment and molecular alterations, are summarized. Based on these biologic insights, novel therapies currently under investigation and those with a strong preclinical biologic rationale including T cell and macrophage checkpoint inhibitors, epigenetic regulators, targeted antibodies, tyrosine kinase inhibitors, and apoptosis modulating therapies are discussed.

The changing therapeutic landscape, burden of disease, and unmet needs in patients with cutaneous T-cell lymphoma

Cutaneous T-cell lymphomas (CTCLs) have a chronic, relapsing course, and the most common subtypes are mycosis fungoides and Sézary syndrome. The disease causes visible skin alterations and can also cause alopecia, pruritus and pain, all of which can impact patients' health-related quality of life (HRQoL). The goal of treatment is to reduce symptoms and prevent disease progression. However, treatment recommendations are often based on low levels of evidence due to the lack of well-designed randomised clinical trials and treatment guidelines, and approved drugs vary considerably across different countries and regions. Currently, available treatments rarely lead to durable remissions and eventually become less effective, meaning patients often require multiple therapy changes. Skin-directed therapies (SDTs) are first-line treatments for early-stage CTCL, whereas systemic therapies may be needed for early-stage disease that does not respond to SDT or for advanced-stage disease. However, patients can experience significant side-effects with these treatments or may be unable to tolerate them. Hence, there is an unmet need for effective therapies with good safety profiles for the treatment of early- and late-stage CTCL. Here, we review current treatment guidelines, investigational and approved treatments, the impact of CTCL on patients' HRQoL, and the treatment of pruritus.

Novel and Future Therapeutic Drugs for Advanced Mycosis Fungoides and Sézary Syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common subtypes of cutaneous T-cell lymphoma. The majority of MF cases present with only patches and plaques and the lesions are usually limited to the skin. On the other hand, in some cases, patients show skin tumors or erythroderma followed by lymph node involvement and rarely visceral organ involvement. SS is a rare, aggressive cutaneous T-cell lymphoma marked by exfoliative erythroderma, lymphadenopathy, and leukemic blood involvement. Because patients with relapsed or refractory MF/SS display a poor prognosis and the current treatment options are characterized by high rates of relapse, there is unmet need for the efficient treatment. This review provides a discussion of the recent and future promising therapeutic approaches in the management of advanced MF/SS. These include mogamulizumab, brentuximab vedotin, alemtuzumab, immune checkpoint inhibitors, IPH4102 (anti-KIR3DL2 antibody), histone deacetylase inhibitors (vorinostat, romidepsin, panobinostat, belinostat, and resminostat), pralatrexate, forodesine, denileukin diftitox, duvelisib, lenalidomide, and everolimus.

E7777 in Japanese patients with relapsed/refractory peripheral and cutaneous T-cell lymphoma: A phase I study

E7777, a recombinant cytotoxic fusion protein comprising diphtheria toxin fragments A and B and human interleukin-2, shares an amino acid sequence with denileukin diftitox but has improved purity and an increased percentage of active protein monomer species. A phase I study was carried out to evaluate the tolerability, safety, pharmacokinetics, and antitumor activity of E7777 in Japanese patients with relapsed/refractory peripheral and cutaneous T-cell lymphoma. E7777 (6, 12, and expanded 9 μg/kg/day) was given to 13 patients by i.v. infusion on five consecutive days per 21-day cycle. Dose-limiting toxicities, including increased alanine aminotransferase, hyponatremia (n = 2), hypokalemia, lymphopenia, fatigue, hypoalbuminemia, rash, and increased lipase (n = 1), were observed in all three patients in the 12 μg/kg/day cohort, whereas two of six patients in the 9 μg/kg/day cohort showed decreased appetite or fatigue. The maximum tolerated and recommended dose of E7777 was 9 μg/kg/day for five consecutive days per 21-day cycle. The objective response rate was 38% (5/13) and did not appear to depend on tumor expression of CD25. E7777 was well tolerated, assuming careful management of adverse events during treatment, and preliminary but clinically meaningful antitumor activity was observed. Subsequent studies of E7777 for T-cell lymphomas are warranted. This study was registered with www.ClinicalTrials.gov (NCT1401530).

Current systemic therapeutic options for advanced mycosis fungoides and Sézary syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common cutaneous T-cell lymphomas (CTCLs). Both lack curative options, and advanced-stage carries a poor prognosis. Whilst there are a number of treatments available, achieving and maintaining a durable remission remains challenging. We review current systemic treatment options as monotherapy for advanced-stage MF (IIB-IV), appraising their mechanism of action, analyzing their efficacy, and describing toxicities. Individually, reported overall response rates (ORR) vary widely in the literature and duration of responses are typically short, ranging from 7.5 to 22.4 months. Combined therapy is frequently used in an effort to boost responses, although prospective studies comparing combinations to single agent therapies are rarely conducted. While recent translational research has led to increased understanding of the immunopathogenesis of MF and SS and the development of new treatments, current standard of care therapies are not curative and have low ORR for advanced-stage disease.

Clinical targeting recombinant immunotoxins for cancer therapy

Recombinant immunotoxins (RITs) are proteins that contain a toxin fused to an antibody or small molecules and are constructed by the genetic engineering technique. RITs can bind to and be internalized by cells and kill cancerous or non-cancerous cells by inhibiting protein synthesis. A wide variety of RITs have been tested against different cancers in cell culture, xenograft models, and human patients during the past several decades. RITs have shown activity in therapy of several kinds of cancers, but different levels of side effects, mainly related to vascular leak syndrome, were also observed in the treated patients. High immunogenicity of RITs limited their long-term or repeat applications in clinical cases. Recent advances in the design of immunotoxins, such as humanization of antibody fragment, PEGylation, and modification of human B- and T-cell epitopes, are overcoming the above mentioned problems, which predict the use of these immunotoxins as a potential therapeutic method to treat cancer patients.

Panoptic clinical review of the current and future treatment of relapsed/refractory T-cell lymphomas: Cutaneous T-cell lymphomas

Primary cutaneous T-cell lymphomas (CTCLs), such as mycosis fungoides and Sézary syndrome, are a rare group of non-Hodgkin lymphomas, usually treated using a multimodal approach. Unfortunately, many patients go on to develop relapsed/refractory disease. Systemic treatment for relapsed/refractory CTCL has historically relied on chemotherapies and interferons, and while active, responses are often short-lived. Three drugs are now approved in the US to treat relapsed/refractory CTCL including the oral retinoid, bexarotene, and histone deacetylase inhibitors, romidepsin and vorinostat. Although response rates are typically <35%, romidepsin and vorinostat can induce some durable responses in heavily pretreated patients and alleviate bothersome symptoms, such as pruritus. New studies indicate that the anti-CD30 antibody-drug conjugate brentuximab vedotin, anti-CCR4 antibody mogamulizumab, and fusion protein immunotoxin A-dmDT390-bisFv(UCHT1) may be particularly active in this setting. In this paper, we present an exhaustive review of the clinical data on current and possible future drug treatment options for relapsed/refractory CTCL.

CD30 As a Target for the Treatment of Cutaneous T-Cell Lymphoma

A 72-year-man presented with a 7-month history of progressive patches and plaques over the trunk and limbs. A skin biopsy confirmed mycosis fungoides (MF). After staging investigations, he was considered to have T2N0M0B0 (stage Ib) disease and began ultraviolet (UV) B phototherapy. Despite initial response, his disease progressed after 4 months, with enlarging patches and plaques but without nodal involvement. As second-line therapy, he received interferon alfa-2b (IFN--2b) 2.7 MU daily, which he tolerated well. He again experienced initial partial response (PR), but by 18 months, he had experienced tumor progression, with patches, plaques, and multiple tumors over the body (up to 3 cm; Fig 1). Biopsy of a neck tumor demonstrated tumor-stage MF,with no evidence of large-cell transformation. Approximately 30% of lymphocytes strongly expressed CD30. CD25 was negative. He began treatment with oral methotrexate 20mg per week, which he tolerated well, and achieved a PR lasting 7 months before multiple plaque and tumor lesions recurred, along with the development of inguinal lymphadenopthy. Biopsy of the skin lesions confirmed the same disease, and [18F]fluorodeoxyglucose–positron emission tomography demonstrated avidity in inguinal and internal iliac nodes, with lymphadenopathy measuring up to 3.5 cm. He has been referred for consideration of further systemic therapy.

Primary cutaneous T-cell lymphoma (mycosis fungoides and Sézary syndrome): part II. Prognosis, management, and future directions

Both mycosis fungoides (MF) and Sézary syndrome (SS) have a chronic, relapsing course, with patients frequently undergoing multiple, consecutive therapies. Treatment is aimed at the clearance of skin disease, the minimization of recurrence, the prevention of disease progression, and the preservation of quality of life. Other important considerations are symptom severity, including pruritus and patient age/comorbidities. In general, for limited patch and plaque disease, patients have excellent prognosis on ≥1 topical formulations, including topical corticosteroids and nitrogen mustard, with widespread patch/plaque disease often requiring phototherapy. In refractory early stage MF, transformed MF, and folliculotropic MF, a combination of skin-directed therapy plus low-dose immunomodulators (eg, interferon or bexarotene) may be effective. Patients with advanced and erythrodermic MF/SS can have profound immunosuppression, with treatments targeting tumor cells aimed for immune reconstitution. Biologic agents or targeted therapies either alone or in combination--including immunomodulators and histone-deacetylase inhibitors--are tried first, with more immunosuppressive therapies, such as alemtuzumab or chemotherapy, being generally reserved for refractory or rapidly progressive disease or extensive lymph node and metastatic involvement. Recently, an increased understanding of the pathogenesis of MF and SS with identification of important molecular markers has led to the development of new targeted therapies that are currently being explored in clinical trials in advanced MF and SS.