Liposomal daunorubicin (DaunoXome) for treatment of poor-risk acute leukemia

A multifunctional PEGylated liposomal-encapsulated sunitinib enhancing autophagy, immunomodulation, and safety in renal cell carcinoma

BACKGROUND

Sunitinib is a multikinase inhibitor used to treat patients with advanced renal cell carcinoma (RCC). However, sunitinib toxicity makes it a double-edged sword. Potent immune modulation by sunitinib extends to nuclear interactions. To address these issues, there is an urgent need for delivery vectors suitable for sunitinib treatment.

METHODS

We developed PEGylated liposomes as delivery vectors to precisely target sunitinib (lipo-sunitinib) to RCC tumors. Further investigations, including RNA sequencing (RNA-seq), were performed to evaluate transcriptomic changes in these pathways. DiI/DiR-labeled lipo-sunitinib was used for the biodistribution analysis. Flow cytometry and immunofluorescence (IF) were used to examine immune modulation in orthotopic RCC models.

RESULTS

The evaluation of results indicated that lipo-sunitinib precisely targeted the tumor site to induce autophagy and was readily taken up by RCC tumor cells. In addition, transcriptomic assays revealed that following lipo-sunitinib treatment, autophagy, antigen presentation, cytokine, and chemokine production pathways were upregulated, whereas the epithelial-mesenchymal transition (EMT) pathway was downregulated. In vivo data provided evidence supporting the inhibitory effect of lipo-sunitinib on RCC tumor progression and metastasis. Flow cytometry further demonstrated that liposunitinib increased the infiltration of effector T cells (Teffs) and conventional type 1 dendritic cells (cDC1s) into the tumor. Furthermore, systemic immune organs such as the tumor-draining lymph nodes, spleen, and bone marrow exhibited upregulated anticancer immunity following lipo-sunitinib treatment.

CONCLUSION

Our findings demonstrated that lipo-sunitinib is distributed at the RCC tumor site, concurrently inducing potent autophagy, elevating antigen presentation, activating cytokine and chemokine production pathways, and downregulating EMT in RCC cells. This comprehensive approach significantly enhanced tumor inhibition and promoted anticancer immune modulation.

Immunoliposomes in Acute Myeloid Leukaemia Therapy: An Overview of Possible Targets and Obstacles

Acute Myeloid Leukaemia (AML) is the neoplastic transformation of Hematopoietic Stem Cells (HSC) and relapsed disease is a major challenge in the treatment. Despite technological advances in the field of medicine and our heightened knowledge regarding the pathogenesis of AML, the initial therapy of "7+3" Cytarabine and Daunorubicin has remained mainly unchanged since 1973. AML is a disease of the elderly, and increased morbidity in this patient group does not allow the full use of the treatment and drug-resistant relapse is common. Nanocarriers are drug-delivery systems that can be used to transport drugs to the bone marrow and target Leukemic Stem Cells (LSC), conferring less side-effects compared to the free-drug alternative. Nanocarriers also can be used to favour the transport of drugs that otherwise would not have been used clinically due to toxicity and poor efficacy. Liposomes are a type of nanocarrier that can be used as a dedicated drug delivery system, which can also have active ligands on the surface in order to interact with antigens on the target cells or tissues. In addition to using small molecules, it is possible to attach antibodies to the liposome surface, generating so-called immunoliposomes. By using immunoliposomes as a drug-delivery system, it is possible to minimize the toxic side effects caused by the chemotherapeutic drug on healthy organs, and at the same time direct the drugs towards the remaining AML blasts and stem cells. This article aims to explore the possibilities of using immunoliposomes as a drug carrier in AML therapy. Emphasis will be on possible target molecules on the AML cells, leukaemic stem cells, as well as bone marrow constituents relevant to AML therapy. Further, some conditions and precautions that must be met for immunoliposomes to be used in AML therapy will be discussed.

Daunorubicin and cytarabine for certain types of poor-prognosis acute myeloid leukemia: a systematic literature review

INTRODUCTION

Induction chemotherapy based on anthracyclines and cytarabine (Ara-C) combination remains the standard of care for acute myeloid leukemia (AML) patients who are considered candidate for intensive and curative approaches. However, the toxicity of this regimen is high, with disappointing clinical outcomes among the so-called poor-prognosis AML subsets, which generally refer to patients with adverse cytogenetic risk, secondary AML including therapy-related AML, poor-prognosis mutations, especially FLT3-ITD, and relapse/refractory AML. Areas covered: To the best of our knowledge, the role and efficacy of 7 + 3 schedules containing daunorubicin (DNR) and Ara-C for certain types of poor-prognosis AML has not been systematically assessed. A critical approach to the role of DNR and Ara-C induction could be relevant to establish which patients should be enrolled in clinical trials using novel therapies. Expert commentary: In this regard, a recent randomized clinical trial (RCT) showed improved results in older patients with sAML or high-risk cytogenetics who received CPX-351 compared with standard 7 + 3 combination. We perform a systematic literature review to analyze the clinical outcomes reported with DNR plus Ara-C regimens in adult patients with poor-prognosis AML, the use of liposomal formulations of DNR and Ara-C and the RCTs which compared standard 7 + 3 with the addition of a third drug.

An overview on the current status of cancer nanomedicines

PURPOSE

Cancer remains a significant cause of morbidity and mortality across the globe. A recent report suggests around 14.1 million new cases and 8.2 million cancer-related deaths, which are expected to reach 21.7 million and 13 million by 2030 worldwide, respectively.

MATERIALS AND METHODS

Because of highly complex mechanisms of cancer progression, it is important to explore and develop new innovative technologies which are more efficient compared with presently available treatment options.

RESULTS

Currently, chemotherapy, radiation and surgery are the most commonly used cancer treatment methods. In the last decade, nanomedicine emerged as an alternative treatment option that uses specific drug-delivery systems, improves efficacy of drugs and reduces detrimental side effects to normal tissues.

CONCLUSION

In this review, we have summarized cancer nanomedicines (active and passive drug delivery) available in the market. We have also discussed other nanomedicines that are at different stages of clinical trials.

Long-term Results of the Risk-adapted Treatment for Childhood B-Cell Acute Lymphoblastic Leukemia: Report From the Japan Association of Childhood Leukemia Study ALL-97 Trial

PURPOSE

This study was conducted as the first clinical trial by Japan Association of Childhood Leukemia Study to improve the outcome of B-cell acute lymphoblastic leukemia and explore a less toxic reinduction block.

PATIENTS AND METHODS

From 1997 to 2002, 563 patients with B-cell acute lymphoblastic leukemia aged 1 to 15 years were enrolled. The patients were assigned into 4 risk groups (standard, intermediate, high, or extremely high risk) and treated with regimens intensified according to the risk. Two randomized trials were conducted to compare 2 regimens with and without a 3-week reinduction therapy in the standard-risk group, and to compare the efficacy of pirarubicin with daunorubicin in the intermediate-risk and high-risk groups. Prophylactic cranial irradiation was restricted in patients with high or extremely high risk.

RESULTS

The event-free survival (EFS) rate at 10 years for all patients was 77.0%. Those in the standard-risk to extremely high-risk groups were 79.3%, 72.5%, 71.7%, and 66.3%, respectively. The 15-week induction/consolidation not followed by reinduction produced 76.4% of the EFS at 10 years comparable with the regimen with reinduction therapy. Pirarubicin at 25 mg/m administered 11 times throughout the treatment produced the EFS comparable with daunorubicin at 30 mg/m.

CONCLUSION

The trial produced high survival rates in NCI-HR patients, although the outcomes in NCI-SR patients were not satisfactory possibly due to less intensive central nervous system-directed therapy.

Acute and late toxicities of pirarubicin in the treatment of childhood acute lymphoblastic leukemia: results from a clinical trial by the Japan Association of Childhood Leukemia Study

BACKGROUND

Anthracyclines are used to treat childhood acute lymphoblastic leukemia (ALL). Even when administered at low doses, these agents are reported to cause progressive cardiac dysfunction. We conducted a clinical trial comparing the toxicities of two anthracyclines, pirarubicin (THP) and daunorubicin (DNR), in the treatment of childhood ALL. The results from our study that relate to acute and late toxicities are reported here.

METHODS

276 children with B-ALL were enrolled in the trial from April 1997 to March 2002 and were randomly assigned to receive a regimen including either THP (25 mg/m² × 11) or DNR (30 mg/m² × 11). Acute toxicity was prospectively assessed based on the National Cancer Institute Common Toxicity Criteria. Acute hematological toxicity was also examined via some parameters. Patients with event-free survival of >5 years were retrospectively surveyed for cardiac function at 5 and 10 years and at the most recent assessment more than 10 years from the onset of ALL.

RESULTS

Acute hematological toxicity in the early phase was more significant in the THP arm. Based on ultrasound cardiography, cardiac function was impaired in both groups during the follow-up period, but there was no significant difference between the groups except for a greater decline in fractional shortening on ultrasound cardiography in the DNR arm.

CONCLUSIONS

While acute hematological toxicity was more significant in the THP arm, THP also appeared to be less cardiotoxic. However, the evaluation of late cardiotoxicity was limited because only a few subjects were followed beyond 10 years after ALL onset. Considering that the THP regimen produced an EFS rate comparable with that of the DNR regimen, the efficacy and toxicity of THP at reduced doses should be studied in order to identify potentially safer regimens.

Liposomal daunorubicin, fludarabine, and cytarabine (FLAD) as bridge therapy to stem cell transplant in relapsed and refractory acute leukemia

Therapeutic options for patients with relapsed or refractory acute leukemia are still undefined and often unsatisfactory. We report the outcome of 79 patients with relapsed-refractory acute leukemia treated with fludarabine, cytarabine, and liposomal daunorubicin (FLAD regimen) followed by hematopoietic stem cell transplantation (HSCT), when clinically indicated, between May 2000 and January 2013. Forty-one patients had acute myeloid leukemia (AML), and 38 had acute lymphoblastic leukemia (ALL). Two patients with myeloid blast crises of CML and three with lymphoid blast crises were included in the AML and ALL subgroups, respectively. Median age was 48 years (range 13-77). FLAD was well tolerated with negligible, nonhematological toxicity. Six patients (7.5 %) died before response evaluation. Forty-seven patients achieved hematologic complete response (CR). Complete remission rate was 53 and 65 % among AML and ALL patients, respectively. No CR was recorded among 11 refractory AML patients. Twenty-four patients (30 %) underwent HSCT. Nine patients received stem cells from an HLA identical sibling, and 15 from an alternative donor (3 unrelated matched, 12 haploidentical sibling). Median overall survival in AML and ALL patients receiving FLAD therapy was 9 and 8 months, respectively. A 5-year projected OS for patients receiving the whole program (FLAD + HSCT) was 24 % for AML patients (median survival 43 months), 28 % for ALL patients treated in relapse (median survival 15 months), and 0 % for ALL patients treated for refractory disease. In this paper, we show that FLAD seems to be an effective bridge therapy to HSCT for a part of poor prognosis acute leukemia patients. However, prospective studies are needed to confirm our results.

Relapsed and refractory pediatric acute myeloid leukemia: current and emerging treatments

Survival rates for children with acute myeloid leukemia (AML) exceed 60 % when modern, intensified chemotherapeutic regimens and enhanced supportive care measures are employed. Despite well-recognized improvements in outcomes, primary refractory or relapsed pediatric AML yields significant morbidity and mortality, and improved understanding of this obstinate population along with refined treatment protocols are urgently needed. Although a significant number of patients with refractory or relapsed disease will achieve remission, long-term survival rates remain poor, and efforts to identify therapies which will improve OS are under continuous investigation. The current fundamental goal of such investigation is the achievement of as complete a remission as possible without dose-limiting toxicities, and the progression to hematopoietic stem cell transplantation thereafter. In this review the scope of the problem of relapsed and refractory AML as well as current and emerging chemotherapy options will be discussed.

Phase I/II trial of nanomolecular liposomal annamycin in adult patients with relapsed/refractory acute lymphoblastic leukemia

BACKGROUND

Treatment options for relapsed/refractory ALL in adult patients remain challenging. Annamycin is a highly lipophilic form of the anthracycline doxorubicin with the ability to bypass multidrug resistance mechanisms of cellular drug resistance.

PATIENTS AND METHODS

We performed a phase I/II multicenter, open-label, study to determine the maximally tolerated dose (MTD) of nanomolecular liposomal annamycin in adult patients with refractory ALL.

RESULTS

Thirty-one patients were enrolled; the MTD was determined to be 150 mg/m(2)/d for 3 days. Other than tumor lysis syndrome, there were 3 grade 3 mucositis which comprised the MTD determination. There was also 1 case each of grade 3 diarrhea, typhlitis, and nausea. After determining the MTD, a 10-patient phase IIA trial was conducted. Eight of the patients completed 1 cycle of the 3 days of treatment at the MTD. Of these, 5 (62%) had an efficacy signal with complete clearing of circulating peripheral blasts. Three of these subjects also cleared bone marrow blasts with 1 subsequently proceeding onto successful stem cell transplantation.

CONCLUSION

Single-agent nanomolecular liposomal annamycin appears to be well tolerated, and shows evidence of clinical activity as a single agent in refractory adult ALL.

FLAG-liposomal doxorubicin (Myocet) regimen for refractory or relapsed acute leukemia pediatric patients

Despite the success in treating the majority of children with newly diagnosed acute leukemia, children with relapsed or refractory disease are an exceptionally difficult group of patients to cure. We assessed the combination of fludarabine with cytarabine and granulocyte colony-stimulating factor (FLAG) and nonpegylated liposomal doxorubicin (Myocet) in children with either acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML) refractory to first-line therapy or who had relapsed after risk-tailored chemotherapy. We treated 35 patients with FLAG-Myocet. The median age at treatment was 9 years and 7 months (range, 1 to 18 y). The 94% of ALL patients (16/17) and the 61% AML patients (11/18) achieved complete remission after FLAG-Myocet. A partial response was observed in the 17% of AML patients (3/18). Twenty-eight of 35 (80%) patients received hematopoetic stem cell transplantation in remission induced by FLAG-Myocet regimen. The ALL and AML overall survival at 3 years after FLAG-Myocet is 33% and 38%, respectively. The probability of ALL and AML event-free survival at 3 years after FLAG-Myocet is 33% and 40%, respectively. The probability of ALL and AML disease-free survival at 3 years after hematopoietic stem cell transplantation is 19% and 58%, respectively. Nonhematological toxicity was remarkably low, while almost all patients showed severe hematological toxicity. FLAG-Myocet is an efficient and a well-tolerated regimen that allows nearly all patients to undergo hematopoetic stem cell transplantation. FLAG-Myocet proved to be safe in terms of acute cardiac toxicity although particular care must be taken to reduce infectious complications due to severe myelosuppression. The promising results shown in our study need to be confirmed by larger and possibly randomized trials.

The use of liposomal daunorubicin (DaunoXome) in acute myeloid leukemia

Altered pharmacokinetics of liposomal formulations of drugs can diminish toxicity and allow the administration of the encapsulated drug at high doses. The liposomal formulation of daunorubicin (DaunoXome, L-DNR) has been reported to produce high mean area under the plasma curve (AUC) levels due to a slow distribution of the liposomal moiety into the body and also to reduce the conversion of daunorubicin to the toxic, but inactive, daunorubicinol. Animal and in vitro studies have shown increased intratumor and intracellular levels of the drug, resulting in enhanced cytotoxicity, even in multidrug-resistant cell lines, while normal tissue toxicity, including cardiotoxicity, may be reduced. L-DNR has been tested as a single agent or in combination with arabinosyl cytosine in the treatment of patients with acute myeloid leukemia (AML) in relapse or in patients with newly diagnosed AML or with disease failing initial remission-induction therapy. The results have indicated that L-DNR can be used at high doses, up to 150 mg/m(2) for 3 days, safely with acceptable toxicity. The anti-leukemia activity has been reported to be at least equal or superior to that of free daunorubicin. Mucositis appeared more frequently than cardiotoxicity and high complete remission rates have been reported in patients with AML in first relapse. However, the superiority of L-DNR with regard to efficacy and toxicity will only be shown by prospective clinical studies comparing?L-DNR with free daunorubicin or other regimens. Two comparative trials are currently active in AML patients, one in children and another in the elderly, run by the international BFM and GIMEMA groups, respectively.

Comparison of two regimens for the treatment of elderly patients with acute lymphoblastic leukaemia (ALL)

Acute lymphoblastic leukemia (ALL) represents a rare malignancy in the elderly and few authors have specifically focused on the treatment of ALL in this setting. We recently published the results of a prospective phase II study comprising an induction therapy with vincristine, Daunoxome and dexamethasone (VDXD) given to 15 patients aged 60 years. Here, we update the results after enrolling 17 patients, and we compare these with the results obtained in 17 elderly patients treated according to the GIMEMA ALL 0288 protocol. With the VDXD combination, elderly ALL had a higher CR rate (76.5%) than with the 0288 protocol (41%), and it was likely due to both lower induction mortality (17.5% vs. 35%) and a less resistant disease (6% vs. 24%). Infectious complications were more frequent with the VDXD combination whereas non-hematological side effects were comparable. Despite the similar DFS obtained with the two induction treatments, median EFS (3.9 months with 0288 vs. 12.8 with VDXD; p = 0.0486) and OS (4.5 vs. 21 months; p = 0.0239) were significantly higher with the VDXD regimen. In elderly ALL patients the administration of high-dose daunorubicin as a liposomal compound is feasible and seems able to improve CR rate, EFS and OS without increase in toxicity.

Liposomal daunorubicin versus standard daunorubicin: long term follow-up of the GIMEMA GSI 103 AMLE randomized trial in patients older than 60 years with acute myelogenous leukaemia

This randomized phase III clinical trial explored the efficacy of DaunoXome (DNX) versus Daunorubicin (DNR) in acute myeloid leukaemia (AML) patients aged >60 years. Three hundred and one AML patients were randomized to receive DNR (45 mg/m(2) days 1-3) or DNX (80 mg/m(2) days 1-3) plus cytarabine (AraC; 100 mg/m(2) days 1-7). Patients in complete remission (CR) received a course of the same drugs as consolidation and then were randomized for maintenance with AraC+ all trans retinoic acid or no further treatment. Among 153 patients in the DNR arm, 78 (51.0%) achieved CR, 55 (35.9%) were resistant and 20 (13.1%) died during induction. Among 148 patients in the DNX arm, 73 (49.3%) achieved CR, 47 (31.8%) were resistant and 28 (18.9%) died during induction. Univariate analysis showed no difference as to induction results. After CR, DNX showed a higher incidence of early deaths (12.5% vs. 2.6% at 6 months, P = 0.053) but a lower incidence of relapse beyond 6 months (59% vs. 78% at 24 months, P = 0.064), with a cross in overall survival (OS) and disease-free survival (DFS) curves and a later advantage for DNX arm after 12 months from diagnosis. DNX seems to improve OS and DFS in the long-term follow-up, because of a reduction in late relapses.

Efficacy of liposomal daunorubicin and cytarabine as reinduction chemotherapy in relapsed acute lymphoblastic leukaemia despite expression of multidrug resistance-related proteins

The treatment of relapsed adult acute lymphoblastic leukaemia (ALL) is frequently unsuccessful with current chemotherapy regimens, and often there is an overexpression of multidrug resistance (MDR)-related proteins. Liposomal encapsulation makes daunorubicin (DNR) less sensitive to the efflux effect of P-glycoprotein (PGP), and in vitro data indicate that liposomal-encapsulated DNR (Daunoxome-DNX) is more toxic than DNR against ALL cell lines. In this study, we assessed the in vivo and in vitro efficacy and toxicity of DNX plus cytarabine (Ara-C) as reinduction chemotherapy in 25 relapsed ALL patients (pts). The expression of MDR-related proteins (PGP, MRP1 and LRP) was also analysed. Of the 25 pts, 12 were males and 13 females; median age was 32 yr (range 18-58). Six cases were ALL T and 19 ALL B; eight pts were Ph+ (32%), and nine Bcr-Abl+ (36%). The expression of MDR-related proteins, and DNR and DNX retention and induction of apoptosis in leukaemic cells were evaluated in all cases. Seventeen of 25 (68%) pts were at first relapse and eight (32%) at second or subsequent relapse. The DNX was given in a dose of 80 mg/m(2)/d (days 1-3) in 11/25 pts (44%) and in a dose of 100 mg/m(2)/d (days 1-3) in 14/25 pts (66%). In all pts, Ara-C was administered in a dose of 2 g/m(2) (days 1-5). Twenty pts (80%) achieved a complete remission (CR) and two (8%) entered a partial remission (PR) for an overall response (OR) rate of 88% (22/25), with a tolerable toxicity and without significant cardiotoxicity. Before the start of DNX therapy, 18/25 (72%) cases overexpressed at least one MDR-related protein compared with 9/25 (36%) cases with MDR overexpression at diagnosis (P = 0.01). Taking into account the small number of cases, the response rate was not affected by MDR expression and the in vitro results also showed a higher uptake and apoptotic cell death by DNX compared with DNR. Twelve pts subsequently underwent allogeneic bone marrow transplantation (11 unrelated donor BMT, and one sibling BMT). The overall survival was 39% after 12 months. These data show the efficacy (OR rate 88% and CR rate 80%) of DNX plus Ara-C as reinduction therapy in very poor-risk ALL pts and the response rate seems not to be affected by MDR overexpression. Moreover, the high rate of remissions and the good clinical tolerance in heavily pretreated pts suggest a promising role of DNX in ALL chemotherapy regimens.

Efficacy and safety of liposomal anthracyclines in Phase I/II clinical trials

Preclinical studies have established the pharmacologic advantages of liposomal anthracyclines, including pharmacokinetic profiles after bolus dosing that resemble continuous infusion of conventional anthracyclines, increased drug concentrations in tumor cells compared with the surrounding tissues, and reduced toxicity relative to conventional anthracycline treatment. Based on these studies, many phase I and phase II clinical trials were conducted to assess the safety and potential activity of liposomal anthracyclines in the management of both solid and hematologic tumors. These studies provided valuable insight into the safety of pegylated liposomal doxorubicin (Doxil/Caelyx [PLD]), nonpegylated liposomal doxorubicin (Myocet [NPLD]), and liposomal daunorubicin (DaunoXome [DNX]) over a range of doses, either as single-agent therapy or in combination with other cytotoxic agents. Other liposomal anthracyclines in development may be well tolerated but their activity remains to be elucidated by clinical trials. The available data also suggest that liposomal anthracyclines have activity not only against tumor types with known sensitivity to conventional anthracyclines, but also potentially for tumors that are typically anthracycline-resistant. Despite the availability of clinical data from a wide variety of tumor types and patient populations, further studies of liposomal anthracycline therapy are needed to fully establish their safety, efficacy, and dosing in the treatment of these patients.

[Treatment of cancer and hematological malignancy in elderly people (Part II)]

PURPOSE

Fifty percents of cancer arise in people older than 65-year-old. Most clinical trials in cancer treatment are limited in patients younger than 65-year-old. We review literature-describing particularity of cancer treatment in elderly patients.

CURRENT KNOWLEDGE AND KEY POINTS

Therapeutic decisions should be based on an estimation of the patient's life expectancy, and risks and benefits should be weighted up accordingly. Geriatric oncology is made of a geriatric evaluation of patient and of knowledge of clinical trial about elderly patients.

FUTURE PROSPECTS AND PROJECTS

We present in this issue the principle of geriatric evaluation and the results of recent clinical trial on elderly cancer patients.

Liposomal 4-hydroxy-tamoxifen: effect on cellular uptake and resulting cytotoxicity in drug resistant breast cancer cells in vitro

The study was performed to investigate the potency of liposomal formulations to reduce or to overcome tamoxifen resistance. Therefore, estrogen receptor (ER) positive MCF-7 and ER deficient NCI/ADR cells with different sensitivity to tamoxifen were used. Instead of the parent compound, 4-hydroxytamoxifen (HT) was used as drug, because this metabolite is the most cytotoxic derivative in vitro. Liposomes further contained the membrane-active alkylphospholipid octadecyl-(1,1-dimethyl-piperidino-4-yl)-phosphate (OPP). Cellular uptake of HT during 3-24 h was determined by high performance thin layer chromatography technique (HPTLC). Free HT was taken up time independently by the two cell lines at 1.5-2.1 g HT/g cellular phosphate. Liposomal HT was taken up at a significantly higher degree than free HT in both cell lines, but the uptake was delayed in the sensitive MCF-7 cell line with the highest concentration detected after 24 h (3.5 g/g). Oppositely, the highest amount in the 'resistant' line (2.3 g/g) was already measured after 3 h in NCI/ADR cells. It successively decreased with incubation time. The faster uptake of liposomal HT by the NCI/ADR cells correlated with a stronger and earlier destruction of resistant NCI/ADR cells whereas the sensitive MCF-7 cells were mainly inhibited in their proliferation. Cytolytic effects were observed in both cell lines after extended incubation periods. The combination of HT with an alkylphospholipid further enhanced the cytotoxicity of the formulation. The IC50 in the NCI/ADR cells could be significantly reduced by liposomes combining both drugs to 15.1 microM compared with the IC50 of the free drugs (HT:28.9 microM; OPP: 36.8 microM). It is assumed that the enhanced and accelerated uptake of liposomal HT in the cell line with relative drug resistance can increase the intracellular bioavailability of HT. The results of this study demonstrated that liposomes with encapsulated antiestrogen have a superior cytotoxic effect in resistant breast cancer cells. That coincided with the enhanced therapeutic effect of these vesicles observed in vivo.

The therapy of relapsed acute leukaemia in adults

Although the cure of acute leukaemia has improved significantly, many patients will still relapse and die. The unraveling of the molecular pathogenesis of acute leukaemia has lead to the identification of new prognostic factors and improved the detection of minimal residual disease. The treatment of relapsed acute leukaemia with chemotherapy remains unsatisfactory. Allogeneic or autologous blood and marrow transplant (BMT) can cure a subset of patients with relapsed acute leukaemia. The identification of the graft-vs-leukaemia (GVL) effect has lead to the development of donor lymphocyte infusions to re-induce remission in patients with relapsed leukaemia after allogeneic BMT and also stimulated the development of the less toxic nonmyeloablative allogeneic transplant approach. The identification of molecular targets of therapy and the development of monoclonal antibody-directed therapy has generated optimism. It is possible that combinations of chemotherapy, molecularly directed therapy, and immunotherapy may be combined to cure an increasing proportion of patients with acute leukaemia.

Combination of liposomal daunorubicin (DaunoXome), fludarabine, and cytarabine (FLAD) in patients with poor-risk acute leukemia

Sixty-two patients with high-risk acute leukemia were treated with the FLAD regimen [3 days of treatment with fludarabine 30 mg/m(2), cytarabine (AraC) 2 g/m(2), and liposomal daunorubicin 80 mg/m(2)]. The acute myeloid leukemia (AML) patients were either refractory to standard induction regimens (8), were in first or second relapse (13), or received therapy as first-line treatment [21 patients, 16 were above 60 years of age and 5 had post-myelodysplastic syndrome (MDS) AML]. The acute lymphoblastic leukemia (ALL) patients were treated for relapsed (7) or refractory disease (10). Three patients had chronic myeloid leukemia (CML) in the blastic phase. FLAD was well tolerated by most patients. Ten major infectious complications were recorded while no signs of cardiac toxicity were observed. Five patients (8%) died before day 28 with hypocellular marrow, mainly of infection or hemorrhage, and response could not be evaluated. Complete response rate was 62% and 69% among AML patients treated at diagnosis or for relapsed disease, respectively, and 59% among the ALL patients. Furthermore, FLAD managed to overcome the negative impact of poor prognosis karyotype in ALL patients, since five of the seven patients with t(9;22) or complex karyotype achieved complete remission (CR). Nine patients underwent bone marrow transplantation (BMT). Among the AML patients who were treated at diagnosis or for relapse, the median duration of CR was 7 months (range: 2-18) and 8 months (range: 2-26), respectively. Median survival among these patients was 8 (range: 1-40) and 12 (range: 1-30) months, respectively. Similar values were found in ALL patients. In conclusion, FLAD may be an effective alternative treatment for patients with relapsed AML and for patients with ALL who failed first-line therapy.

Intravenous liposomal delivery of the snake venom disintegrin contortrostatin limits breast cancer progression

Despite significant research in this area, metastatic breast cancer remains a disease with a poor prognosis. Until an effective therapy is developed, it is imperative that new treatment modalities be investigated. In this report, we describe an effective method for delivery of a novel snake venom disintegrin, contortrostatin (CN), in an orthotopic, xenograft model of human mammary cancer in immunodeficient mice. CN (Mr 13,500) is a homodimeric disintegrin isolated from venom of the Southern Copperhead snake. The homodimer possesses two Arg-Gly-Asp sites, which modulate its interaction with integrins on tumor cells and angiogenic vascular endothelial cells. Although our laboratory has previously described the antitumor activity of CN in a mouse model of human mammary cancer, the method of delivery, daily intratumor injection, was not translatable to clinical application. We now describe a clinically relevant method of administering CN, liposomal delivery (LCN). A unique liposomal system has been designed for i.v. administration of a biologically active protein with full retention of biological activity. Pharmacokinetics, biodistribution, platelet reactivity, and immunogenicity of LCN were determined and compared with similar characteristics of native, unencapsulated CN. There are several advantages to liposomal delivery of CN: (1) LCN has a significantly prolonged circulatory half-life compared with native CN; (2) LCN is passively accumulated in the tumor; (3) LCN has no platelet reactivity; and (4) LCN is not recognized by the immune system. Finally, antiangiogenic activity is an important component of CN's mechanism of antitumor action. We have demonstrated that i.v. delivery of LCN leads to potent antiangiogenic activity in the orthotopic, xenograft human mammary tumor model.

Phase I and pharmacokinetic study of a low-clearance, unilamellar liposomal formulation of lurtotecan, a topoisomerase 1 inhibitor, in patients with advanced leukemia

BACKGROUND

OSI-211 is a low-clearance, unilamellar liposomal formulation of a water-soluble camptothecin analogue, lurtotecan. OSI-211 has significant activity in severe combined immunodeficient mouse models of human leukemia.

METHODS

This study was conducted to define the dose-limiting toxicities (DLT) and pharmacokinetics of OSI-211 in patients with refractory myeloid leukemias. Patients with refractory acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myelogenous leukemia in blastic phase (CML-BP) were eligible. OSI-211 was given as an intravenous infusion over 30 minutes daily for 3 days. The starting dose was 1.5 mg/m2 per day (4.5 mg/m2 per course). The dose was escalated by 50% until Grade 2 toxicity was observed and then by 30-35% until the DLT was defined. Serial plasma and urine samples were collected, and drug levels were determined by high-performance liquid chromatography with fluorescence detection.

RESULTS

Twenty patients (18 patients [90%] with AML, and 1 patient each [5%] with MDS and CML-BP) were treated. Mucositis and diarrhea were considered to be the DLTs. The maximum tolerated dose was 3.7 mg/m2 per day. Fourteen of 18 evaluable patients (78%) with AML or MDS achieved transient bone marrow aplasia. The mean systemic clearance of lurtotecan in plasma was 0.946 +/- 1.53 L/hour/m2. Urinary recovery of lurtotecan was 6.66% +/- 5.26% (range, 1.05-18.4%).

CONCLUSIONS

Liposomal encapsulation of lurtotecan altered its metabolism significantly. There was no evident correlation between exposure, as measured by plasma pharmacokinetics of lurtotecan, and clinical response or toxicities. OSI-211 merits further study in hematologic malignancies.