Long-term administration of oral low-dose topoisomerase II inhibitors, MST-16 and VP-16, for refractory or relapsed non-Hodgkin's lymphoma

Low-Dose MST-16/VP-16 Combination Chemotherapy in 9 Patients with Tumor Stage Mycosis Fungoides

BACKGROUND/AIM

MST-16 and VP-16, both of which are topoisomerase II inhibitors, are antitumor agents regularly used to treat malignant lymphoma and small cell lung carcinoma. New therapeutic agents for tumor stage mycosis fungoides (MF) have recently been developed, but their efficacy is limited. We herein retrospectively reported the use of MST-16/VP-16 combination therapy for tumor stage MF at multiple treatment centers and examined their antitumor effect.

METHODS

Five male and four female patients with tumor stage MF were enrolled. Age at the start of therapy ranged from 33 to 80 years (average: 54.5 years), and the previous treatment consisted of R-CHOP, CAVOP-IFN, etc. The protocol for low-dose MST-16/VP-16 combination chemotherapy consisted of 800 mg MST-16 and 25 mg VP-16 administered 5 days per month.

RESULTS

Three of the 9 patients died, but two of the three fatalities were unrelated to MF. A treatment effect was seen in three and 6 patients who showed a complete response and a partial response, respectively. The 5-year and 10-year overall survival rate was 85.7% and 57.1%, respectively. Adverse reactions consisted of 4 cases of nausea and 1 case of leukopenia.

CONCLUSION

The present study demonstrated that the response rate to MST-16/VP-16 combination therapy was 100% and that the treatment effect was relatively long, suggesting that this therapy may be a viable option for treating tumor stage MF.

Clinical feasibility of oral low-dose etoposide and sobuzoxane for conventional chemotherapy-intolerant lymphoma patients

Introduction: In Japan, etoposide or sobuzoxane, a type of topoisomerase II inhibitor, is orally administered in patients with lymphoma who cannot tolerate conventional combination chemotherapy. However, the related clinical data remain to be fully summarized.Areas covered: We evaluate the efficacy and toxicity of etoposide and sobuzoxane.Expert opinion: Previous studies on etoposide or sobuzoxane monotherapy, including those among patients who could not tolerate conventional chemotherapy, suggested a favorable overall response rate (ORR) with moderate gastrointestinal or liver/renal toxicity. As for adult T-cell leukemia/lymphoma, a clinical trial with a limited sample size exhibited an ORR of >70%. Remarkably, the percentage of patients with a poor performance status was high among those receiving etoposide/sobuzoxane. Given a lack of randomized studies, etoposide/sobuzoxane might be a therapeutic option for lymphoma in a palliative setting. In the future, prospective trials with a homologous treatment schedule are warranted, in which the association between clinical efficacy and characteristics of lymphomas, such as specific gene alterations, should be elucidated.

Efficacy of salvage therapy with MTX-HOPE for elderly patients with heavily pretreated non-Hodgkin's lymphoma

Methotrexate, hydrocortisone, vincristine, sobuzoxane, and etoposide (MTX-HOPE) chemotherapy was originally reported in 2007 as a salvage regimen for relapsed or refractory non-Hodgkin’s lymphoma. To clarify the safety and efficacy of this regimen, we retrospectively analyzed patients at our institute. We analyzed 18 patients, including 16 with diffuse large B-cell lymphoma (DLBCL), one with follicular lymphoma (FL), and one with T-cell lymphoma. The median age at MTX-HOPE therapy was 79 (range: 68-87). Ten patients received more than 3 previous chemotherapy regimens. The median period from the initial treatment to the first MTX-HOPE administration was 53 months. No patient had severe renal dysfunction. The overall response rate was 78%, with 39% achieving CR and 39% achieving PR. The median OS and PFS after the initiation of MTX-HOPE were 10 months (range: 0.5-86 months) and 7 months (range: 0.2-86 months), respectively. The one-year OS rate was 44% and the two-year OS rate was 22%. The median number of treatment cycles was 7 (range: 1-46), and 6 patients received more than 10 cycles. Among eight patients who were over 80 years of age, 7 responded to the therapy, and the median OS and PFS of this subgroup were 19 months and 11 months, respectively. All patients tolerated the treatment well, mostly on an outpatient basis, except for one who died from infection and one who developed intracranial hemorrhage. MTX-HOPE may be a promising treatment option for elderly patients with refractory or relapsed malignant lymphoma.

Methotrexate-associated lymphoproliferative disorders with angioimmunoblastic T-cell lymphoma-like features accompanied by gamma-heavy chain disease in a patient with rheumatoid arthritis

Although gamma heavy chain disease (γ-HCD) lesions occasionally morphologically resemble angioimmunoblastic T-cell lymphoma (AITL), no association has been described in detail due to the rarity of the disease. In this report, we present a rare manifestation of methotrexate (MTX)-associated lymphoproliferative disorders (LPDs) with AITL-like features accompanied by γ-HCD in a 75-year-old man with rheumatoid arthritis (RA). A biopsy specimen was evaluated using immunohistochemistry, clonal analyses of immunoglobulin VH and T-cell receptor γ gene rearrangements by polymerase chain reaction, and Sanger sequencing for confirmation of the structure of deleted γ-HCD clones. The histological features characterized by proliferation of CD4- and PD-1-positive medium-sized T cells and arborizing high endothelial venules together with numbers of small lymphocytes, eosinophils, plasma cells, and histiocytes in the background mimicked those of AITL, but did not completely fulfill the diagnostic criteria. Clonal analysis demonstrated that the specimen contained multiple LPDs of both B-cell and T-cell lineages. Sequence analysis confirmed the co-existence of a clone responsible for production of the abnormal heavy chain. This report provides new insights into the pathology of γ-HCD. Multiple host-derived factors (e.g., RA and/or use of MTX) may be responsible for the occurrence of LPDs of multiple lineages within a single lymph node.

Rituximab combined with a small dose of melphalan for a refractory follicular lymphoma patient

A 48-year-old male patient with follicular lymphoma, grade II, stage IV, was treated with CHOP, ESHAP and MACOP-B, resulting in partial remission. After 9 months, the disease progressed and several chemotherapy agents, including three courses of rituximab combined with etoposide, sobuzoxane or methotrexate, only resulted in a stable disease response. However, the fourth course of rituximab combined with a small dose of melphalan produced excellent results and the complete response continued for more than 15 months. It is possible that these two drugs may act synergistically.

Anti-proliferative effects, cell cycle G2/M phase arrest and blocking of chromosome segregation by probimane and MST-16 in human tumor cell lines

Background

Anticancer bisdioxopiperazines, including ICRF-154, razoxane (Raz, ICRF-159) and ICRF-193, are a family of anticancer agents developed in the UK, especially targeting metastases of neoplasms. Two other bisdioxopiperazine derivatives, probimane (Pro) and MST-16, were synthesized at the Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. Cytotoxic activities and mechanisms of Raz (+)-steroisomer (ICRF-187, dexrazoxane), Pro and MST-16 against tumor cells were evaluated by MTT colorimetry, flow cytometry and karyotyping.

Results

Pro was cytotoxic to human tumor cell lines in vitro (IC₅₀<50 μM for 48 h). Four human tumor cell lines (SCG-7901, K562, A549 and HL60) were susceptible to Pro at low inhibitory concentrations (IC₅₀ values < 10 μM for 48 h). Although the IC₅₀ against HeLa cell line of vincristine (VCR, 4.56 μM), doxorubicin (Dox, 1.12 μM) and 5-fluoruouracil (5-Fu, 0.232 μM) are lower than Pro (5.12 μM), ICRF-187 (129 μM) and MST-16 (26.4 μM), VCR, Dox and 5-Fu shows a low dose-related – high cytotoxic activity. Time-response studies showed that the cytotoxic effects of Pro are increased for 3 days in human tumor cells, whereas VCR, Dox and 5-Fu showed decreased cytotoxic action after 24 h. Cell cycle G₂/M phase arrest and chromosome segregation blocking by Pro and MST-16 were noted. Although there was similar effects of Pro and MST-16 on chromosome segregation blocking action and cell cycle G₂/M phase arrest at 1- 4 μM, cytotoxicity of Pro against tumor cells was higher than that of MST-16 in vitro by a factor of 3- 10 folds. Our data show that Pro may be more effective against lung cancer and leukemia while ICRF-187 and MST-16 shows similar IC₅₀ values only against leukemia.

Conclusion

It suggests that Pro has a wider spectrum of cytotoxic effects against human tumor cells than other bisdioxopiperazines, especially against solid tumors, and with a single cytotoxic pathway of Pro and MST-16 affecting chromosome segregation and leading also to cell G₂/ M phase arrests, which finally reduces cell division rates. Pro may be more potent than MST-16 in cytotoxicity. High dose- and time- responses of Pro, when compared with VCR, 5-Fu and Dox, were seen that suggest a selectivity of Pro against tumor growth. Compounds of bisdioxopiperazines family may keep up their cytotoxic effects longer than many other anticancer drugs.

Catalytic topoisomerase II inhibitors in cancer therapy

The nuclear enzyme DNA topoisomerase II is a major target for antineoplastic agents. All topoisomerase II-directed agents are able to interfere with at least one step of the catalytic cycle. Agents able to stabilize the covalent DNA topoisomerase II complex (also known as the cleavable complex) are traditionally called topoisomerase II poisons, while agents acting on any of the other steps in the catalytic cycle are called catalytic inhibitors. Thus, catalytic topoisomerase II inhibitors are a heterogeneous group of compounds that might interfere with the binding between DNA and topoisomerase II (aclarubicin and suramin), stabilize noncovalent DNA topoisomerase II complexes (merbarone, ICRF-187, and structurally related bisdioxopiperazine derivatives), or inhibit ATP binding (novobiocin). Some, such as fostriecin, may also have alternative biological targets. Whereas topoisomerase II poisons are used solely for their antitumor activities, catalytic inhibitors are utilized for a variety of reasons, including their activity as antineoplastic agents (aclarubicin and MST-16), cardioprotectors (ICRF-187), or modulators in order to increase the efficacy of other agents (suramin and novobiocin). In this review, the mechanism and biological activity of different catalytic inhibitors is described, with emphasis on therapeutically used compounds. We will then discuss future development and applications of this interesting class of compounds.