Unexpected hepatotoxicities in patients with non-Hodgkin's lymphoma treated with irinotecan (CPT-11) and etoposide

Engineering Multishelled Nanostructures Enables Stepwise Self-Degradability for Drug-Release Optimization

The balance between degradability and drug release kinetics is a major challenge for the development of drug delivery systems. Here we develop hierarchically structured nanoparticles comprising multiple noncontact silica shells using an amorphous calcium carbonate template. The system could be degraded in a sequential fashion on account of the molecularly engineered multishelled structures. The hydrolysis rate of drug-containing cores is inversely correlated with the nanoparticle concentration due to the shielding effect of the hierarchical nanostructure and could be exploited to regulate the release kinetics. Specifically, multishelled nanospheres show a low drug release rate with high doses that increases steadily as the concentration decreases due to continuous degradation, thus stabilizing the local drug concentration for effective tumor therapy. Moreover, the nanoparticles could be eventually degraded completely, which may reduce their health risks. This kind of hierarchically structured silica-based nanoparticle could serve as a sustainable drug depot and provides a new avenue for tumor treatment.

Irinotecan side effects relieved by the use of HI-6 oxime: in vivo experimental approach

Some compounds, although not primarily designed as supportive drugs in chemotherapy, are promising candidates for clinical use. The ability of HI-6 oxime to relieve the side effects of irinotecan was recently determined in vitro. In this animal study, we investigated the efficacy of HI-6 in vivo, when given as a pre-treatment and concomitantly with irinotecan. We evaluated the cholinesterase (ChE)/acetylcholinesterase (AChE) activity, the levels of oxidative stress markers, DNA damage and the radical scavenging capacity of HI-6. Both HI-6 and irinotecan inhibited ChE/AChE activity but showed different levels of ChE inhibition in plasma and AChE inhibition in the liver and brain tissue. We also observed a weak antioxidant capacity of HI-6, undiscovered until now, and found an acceptable genotoxicity profile in three types of somatic cells in rats. The in vivo erythrocyte micronucleus assay showed that HI-6 did not significantly change either the frequency of micronuclei or the ratio of polychromatic and normorchromatic erythrocytes. Taken together, our results provide a good argument in favour of HI-6 as a promising molecule for further studies and eventual use in humans.

Phase II study of the CPT-11, mitoxantrone and dexamethasone regimen in combination with rituximab in elderly patients with relapsed diffuse large B-cell lymphoma

Standard treatment for elderly patients with relapsed or refractory DLBCL has not been established. CPT-11 has a broad spectrum of anticancer activities including a cytotoxic effect in a variety of malignant tumors. The results of combined treatment with CPT-11 and rituximab have not been reported. The R-CMD regimen was given to elderly patients with relapsed or refractory DLBCL. The safety and efficacy of this regimen were studied. In addition, the serum nm23-H1 level was determined to study whether or not it can serve as a prognostic factor. Thirty elderly patients with DLBCL were studied. The main non-hematological toxicities were infusion-related adverse events. Grade 3/4 hematological toxicity was seen in 19 patients. Following R-CMD treatment, the BNP and troponin T levels did not increase. The CR rate was 57%, PR rate was 17%, 2-year survival rate was 45.2%, and PFS rate was 37.2%. Patients with serum nm23-H1 levels of higher than 80 ng/mL before the treatment showed significantly poorer prognosis. The serum nm23-H1 level of the 30 subjects before the treatment was elevated at 39.4 +/- 41.3 ng/mL, but it significantly decreased only in the subset of patients who achieved CR. The R-CMD regimen was safe in elderly patients with DLBCL. No new signs of cardiotoxicity were observed with this regimen. It was also effective in patients with relapsed or refractory DLBCL who had previously used DXR.

Clinical trials for malignant lymphoma in Japan

The results of the clinical trials by the Lymphoma Study Group of the Japan Clinical Oncology Group (JCOG-LSG) and those of the industry-supported trials mainly conducted by the members of JCOG-LSG are summarized. In the treatment of advanced aggressive non-Hodgkin's lymphoma (NHL), we investigated the efficacy of granulocyte colony-stimulating factor (G-CSF)-supported, dose-intensified strategies. Based on the results of a randomized phase II study (JCOG9505), we conducted a phase III study, JCOG9809, comparing CHOP and biweekly CHOP. However, JCOG9809 was terminated early based on the results of a planned interim analysis, because it was deemed highly unlikely that biweekly CHOP would be superior to standard CHOP. For aggressive ATL, a G-CSF-supported, dose-intensified, multi-agent regimen (JCOG9303; LSG15) showed superior efficacy to our historical controls. To establish a new standard for ATL, we conducted a phase III study, JCOG9801, comparing LSG15 and biweekly CHOP. To develop new agents for lymphoid malignancies, we focused on irinotecan hydrochloride, interferon-alpha, cladribine and oral fludarabine. Among them, cladribine and oral fludarabine are promising for indolent B-cell malignancies. The Japanese phase I and II studies of rituximab, a chimeric anti-CD20 monoclonal antibody, in relapsed indolent and aggressive B-NHL showed high efficacy with minimal toxicities, which led us to conduct combination studies with chemotherapy for B-NHL. In addition, a phase I study of a radiolabeled anti-CD20 antibody (ibritumomab tiuxetan) was completed in 2003, and a phase II study for indolent B-NHL will be initiated. The multicenter trials by the JCOG-LSG and industry-supported new agent studies will contribute to further improvement in the treatment of malignant lymphoma.

Topoisomerase inhibitor camptothecin sensitizes mouse hepatocytes in vitro and in vivo to TNF-mediated apoptosis

Topoisomerases are nuclear enzymes that maintain and modulate DNA structure. Inhibitors of topoisomerases like camptothecin (CPT), etoposide, and others are widely used antitumor drugs that interfere with transcription, induce DNA strand breaks, and trigger apoptosis preferentially in dividing cells. Because transcription inhibitors (actinomycin D, galactosamine, alpha-amanitin) sensitize primary hepatocytes to the cytotoxic action of tumor necrosis factor (TNF), we reasoned whether topoisomerase inhibitors would act similarly. CPT alone was not toxic to primary cultured murine hepatocytes. When incubated with CPT, murine hepatocytes displayed an inhibition of protein synthesis and were thereby rendered sensitive to apoptosis induction by TNF. Apoptosis was characterized by morphology (condensed/fragmented nuclei, membrane blebbing), caspase-3-like protease activity, fragmentation of nuclear DNA, and late cytolysis. Hepatocytes derived from TNF receptor-1 knockout mice were resistant to CPT/TNF-induced apoptosis. CPT treatment completely abrogated the TNF-induced NF-kappa B activation, and mRNA expression of the antiapoptotic factors TNF-receptor associated factor 2, FLICE-inhibitory protein, and X-linked inhibitor of apoptosis protein was also inhibited by CPT. The caspase inhibitors benzyloxycarbonyl-Val-Ala-Asp-(OMe)-fluoromethylketone (zVAD-fmk) and benzyloxycarbonyl-Asp(OMe)-Glu(OMe)-Val-Asp(OMe)-chloromethylketone (zDEVD-fmk), as well as depletion of intracellular ATP by fructose prevented CPT/TNF-induced apoptosis. In vivo, CPT treatment sensitized mice to TNF-induced liver damage. In conclusion, the combination of topoisomerase inhibition and TNF blocks survival signaling and elicits a type of hepatocyte death similar to actinomycin D/TNF or galactosamine/TNF. During antitumor treatment with topoisomerase inhibitors, an impaired immune function often results in opportunistic infections, a situation where the systemic presence of TNF might be critical for the hepatotoxicity reported in clinical topoisomerase inhibitor studies.

Irinotecan hydrochloride for the treatment of recurrent and refractory non-Hodgkin lymphoma: a single institution experience

BACKGROUND

Irinotecan hydrochloride (CPT-11) has a broad range of antitumor activity and has demonstrated little cross-resistance with doxorubicin or vincristine. In the current study, the authors investigated the efficacy and adverse effects of irinotecan in the treatment of recurrent and refractory non-Hodgkin lymphoma, for which current therapies appear to be unsatisfactory.

METHODS

Irinotecan was administered by intravenous infusion at a dose of 40 mg/m(2)/day for 3 days, and this regimen was repeated 2-3 times at weekly intervals, followed by 2 weeks off therapy. The subjects were 48 patients with recurrent or refractory non-Hodgkin lymphoma. The histologic classification (Working Formulation) was low grade in 8 patients, intermediate grade in 36 patients, high grade in 1 patient, and other (angiocentric lymphoma, Ki-1 lymphoma, and unidentified) in 3 patients.

RESULTS

Forty-five patients were determined to be evaluable. Therapy resulted in a complete disease remission in 2 patients and a partial remission in 15 patients. The response rate was 37.8%. The median duration of response was 64 days and the median time to disease progression was 77 days. The median survival time was 422 days. Major adverse reactions included myelosuppression and gastrointestinal toxicity. Leukopenia, anemia, and thrombocytopenia of Grade 3 or 4 (according to the National Cancer Institute Common Toxicity Criteria) was observed in 63.0%, 30.4%, and 6.5% of the patients, respectively, and Grade 3 or 4 diarrhea occurred in 30.4% of patients. Treatment was withdrawn because of diarrhea in three patients. Because of myelosuppression and diarrhea, approximately 67% of the patients required changes to the regimen, including dose reduction, prolongation of the interval between treatments, and reducing the number of days of consecutive treatment.

CONCLUSIONS

The results of the current study suggest the activity of irinotecan as salvage therapy for patients with recurrent and refractory non-Hodgkin lymphoma. However, the optimum dosing schedule remains to be determined.

Chemotherapy with irinotecan (CPT-11), a topoisomerase-I inhibitor, for refractory and relapsed non-Hodgkin's lymphoma

Irinotecan hydrochloride (CPT-11), a DNA topoisomerase-I inhibitor, is now widely used in the treatment of various solid tumors, including colorectal, gastric, breast, lung, and ovarian cancer. Despite the good response shown in the late phase-II study, CPT-11 was not often employed in the treatment of malignant lymphoma, mainly because of severe leukopenia and diarrhea caused by the recommended schedule: 40 mg/m2 of CPT-11 on days 1 to 3, 8 to 10, 15 to 17, then discontinued for at least 2 weeks. In clinical use, administration of CPT-11 had to be ceased on days 15 to 17 in almost all cases, and on days 8 to 10 in a considerable number of patients. Subsequently, a lower dose schedule (less than 40 mg/m2) was developed. Our phase II trial employing a reduced dose of CPT-11 on days 1 and 2, plus ADM on day 3 with 3-week interval in patients with refractory and relapsed NHL showed a fairly good response of relapsed B-cell lymphoma and a substantial response of T-cell lymphoma with acceptable toxicity. The combination of a topoisomerase-I inhibitor (CPT-11) and a topoisomerase-II inhibitor is an interesting concept for the treatment of NHL. Another phase II trial in combination with CPT-11 and other anti-cancer drugs, particularly cisplatin or topoisomerase-II inhibitors, is warranted. A superior salvage chemotherapy regimen could be found in the future by investigating combinations of low-dose CPT-11 and cisplatin or topoisomerase-II inhibitors.