Phase II study of oral platinum drug JM216 as first-line treatment in patients with small-cell lung cancer

Synthesis and Cytotoxicity of Water-Soluble Dual- and Triple-Action Satraplatin Derivatives: Replacement of Equatorial Chlorides of Satraplatin by Acetates

Pt(II) complexes, such as cisplatin and oxaliplatin, are in widespread use as anticancer drugs. Their use is limited by the toxic side effects and the ability of tumors to develop resistance to the drugs. A popular approach to overcome these drawbacks is to use their kinetically inert octahedral Pt(IV) derivatives that act as prodrugs. The most successful Pt(IV) complex in clinical trials to date is satraplatin, cct-[Pt(NH₃)(c-hexylamine)Cl₂(OAc)₂], that upon cellular reduction releases the cytotoxic cis-[Pt(NH₃)(c-hexylamine)Cl₂]. In an attempt to obtain water-soluble and more effective cytotoxic Pt(IV) complexes, we prepared a series of dual- and triple-action satraplatin analogues, where the equatorial chlorido ligands were replaced with acetates and the axial ligands include innocent and bioactive ligands. Replacement of the chlorides with acetates enhanced the water solubility of the compounds and, with one exception, all of the compounds were very stable in buffer. In general, compounds with one or two axial hydroxido ligands were reduced by ascorbate significantly more quickly than compounds with two axial carboxylates. While replacement of the chlorides with acetates in satraplatin led to a reduction in cytotoxicity, the dual- and triple-action analogues with equatorial acetates had low- to sub-micromolar IC₅₀ values in a panel of eight cancer cells. The triple-action compound cct-[Pt(NH₃)(c-hexylamine)(OAc)₂(PhB)(DCA)] was active in all cell lines, causing DNA damage that induced cell cycle inhibition and apoptosis. Its good activity against CT26 cells in vitro translated into good in vivo efficacy against the CT26 allograft, an in vivo model with intrinsic satraplatin resistance. This indicates that multiaction Pt(IV) derivatives of diamine dicarboxylates are interesting anticancer drug candidates.

Advances in oral delivery of anti-cancer prodrugs

INTRODUCTION

Most anticancer drugs have poor aqueous solubility and low permeability across the gastrointestinal tract. Furthermore, extensive efflux by P-glycoproteins (P-gp) in the small intestine also limits the efficient delivery of anticancer drugs via oral route. Area covered: This review explores the prodrug strategy for oral delivery of anticancer drugs. Different categories of oral anticancer prodrugs along with recent clinical studies have been comprehensively reviewed here. Furthermore, novel anticancer prodrugs such as polymer-prodrugs and lipid-prodrugs have been discussed in detail. Finally, various nanocarrier-based approaches employed for oral delivery of anticancer prodrugs have also been discussed. Expert opinion: Premature degradation of anticancer prodrugs in the gastrointestinal tract could lead to variable pharmacokinetics and undesired toxicity. Despite their increased aqueous solubility, the oral bioavailability of several anticancer prodrugs are limited by their poor permeability across the gastrointestinal tract. These limitations can be overcome by the use of functional excipients (polymers, lipids, amino acids/dipeptides), which are specifically absorbed via transporters and receptor-mediated endocytosis. Oral delivery of anticancer prodrugs using nanocarrier-based drug delivery system is a recent development; however it should be justified based on the comparative advantages of encapsulating prodrug in a nanocarrier versus the use of anticancer prodrug molecule itself.

Phase 1 trial and pharmacokinetic study of the oral platinum analog satraplatin in children and young adults with refractory solid tumors including brain tumors

BACKGROUND

Based on pre-clinical and clinical activity in adult refractory tumors, and absence of significant neuro-, nephro-, or oto-toxicity, we conducted a pediatric phase 1 trial to determine the toxicities, maximum tolerated dose (MTD), and pharmacokinetics of satraplatin, an oral platinum analogue, in children and young adults with refractory solid tumors.

PROCEDURE

Satraplatin was administered orally once daily on days 1-5 of a 28-day cycle at dose level (DL) 1 (60 mg/m(2) /dose), and DL2 (80 mg/m(2) /dose). Toxicities, responses, satraplatin pharmacokinetics, and pharmacogenomic expression of specific DNA repair genes were evaluated.

RESULTS

Nine patients received 1-15 cycles (median = 2). The MTD was exceeded at DL2 with delayed prolonged myelosuppression as dose-limiting toxicity (DLT) in 2/4 patients. At DL1, 0/5 patients had DLTs. Common non-DLTs included myelosuppression, gastrointestinal toxicities, fatigue, headache, liver enzyme elevation, and electrolyte abnormalities. No significant neuro-, nephro-, or oto-toxicity was observed. No objective responses were observed but 2 patients experienced prolonged disease stabilization (---6-15 cycles). Satraplatin exposure (day 1 plasma ultrafiltrate area under the curve) was similar at DL1 and DL2. A strong correlation between estimated creatinine clearance and satraplatin pharmacokinetic parameters (clearance, area under the curve, and peak concentration) was observed.

CONCLUSIONS

The MTD of oral satraplatin in children with solid tumors was 60 mg/m(2) /dose daily ×5 days every 28 days, which is lower than the adult recommended dose of 80-120 mg/m(2) /dose. The toxicity profile was similar to adults and delayed myelosuppression was the DLT. No significant neuro-, nephro- or oto-toxicities were observed.

High seroprevalence of human herpesvirus type 8 infection in males with advanced lung carcinoma

Human herpesvirus type 8 (HHV-8) DNA is consistently found in all types of Kaposi's sarcoma, which is prevalent in immunocompromised patients. Patients with advanced lung carcinoma often showed immunologic abnormalities, and prevalence of HHV-8 infection is unclear. In this study, blood samples from 109 lung carcinoma patients and 109 age- and sex-matched healthy controls were analyzed for lymphocyte and monocyte counts, and for antibody, DNA, and genotype of HHV-8. Lung carcinoma patients had significantly lower lymphocyte and higher monocyte counts than healthy controls (p < 0.0001, both). HHV-8 seropositivity was more prevalent in lung carcinoma patients (41.3%), particularly in male patients (50.8%), than in controls (24.8%) (p = 0.01 and 0.002, respectively). The seropositivity was also significantly higher in male (50.8%) than female patients (27.3%, p = 0.01). Titers of HHV-8 antibody in patients also significantly exceeded those in controls (p = 0.004). Under a higher threshold (antibody titer ≥1:160) which is equivalent to that of enzyme-linked immunosorbent assay, lung carcinoma patients still had higher HHV-8 seropositivity than controls (p = 0.006). Three patients with stage IV lung carcinoma were positive for HHV-8 DNA with K1 gene subtype C3, D1, and E, respectively; they had much lower lymphocyte counts (658 ± 132 µL) than patients positive for HHV-8 antibodies only (1,449 ± 873 µL). The study indicates that lung carcinoma patients, particularly males, have a high seroprevalence of HHV-8. HHV-8 DNA detected in the patients with advanced lung carcinoma may be a result of virus reactivation in the immunocompromised status.

An open-label, dose-finding study of the combination of satraplatin and gemcitabine in patients with advanced solid tumors

Purpose: Satraplatin is a third generation oral platinum, which has demonstrated antitumor activity. The aim of this phase I study was to determine the maximum tolerated dose (MTD) of the combination of satraplatin and gemcitabine in patients previously treated with chemotherapy and in patients without prior chemotherapy. Patients and Methods: Two separate MTDs were planned in two different patient groups (those with and without prior chemotherapy treatment). Dose escalations were planned in cohorts of three patients. Tumor measurements were obtained every two cycles. Assessment of response was performed according to Response Evaluation Criteria in Solid Tumors (RECIST criteria v.1.0). Results: Thirty subjects were enrolled. A MTD of gemcitabine 1000 mg/m² days 1 and 8 plus satraplatin 60 mg/m² days 1–3, every 21 days was determined in the prior chemotherapy group. No MTD could be determined for the no prior chemotherapy group treated with this schedule. Five patients completed 12 treatment cycles; 22 serious adverse events (SAE) were observed. Although not an entry criteria, overall confirmed response was observed in 17 (24%) evaluable patients (complete response, CR = 1 and partial response, PR = 3) and in 3/7 (43%) patients with measure prostate cancer lesions. Conclusions: In this phase Ib study, the combination of satraplatin and gemcitabine demonstrated to be safe and efficacious in particular in patients with prostate cancer.

Clinical and pharmacokinetic evaluation of satraplatin

INTRODUCTION

The toxicities of cisplatin, that is, nephrotoxicity, neurotoxicity and emesis, provided the impetus for the development of more tolerable platinum analogs. Satraplatin is an investigational third-generation orally available lipophilic platinum, which has demonstrated safety and antitumor activity in multiple settings.

AREAS COVERED

The clinical activity of satraplatin in metastatic castrate-resistant prostate cancer (mCRPC), breast, lung and other advanced solid tumors is discussed with a focus on its pharmacokinetic properties. The article was formulated using publications found through PubMed search in addition to presentations given at major conferences.

EXPERT OPINION

Satraplatin was associated with dose-limiting myelosuppression, but no significant ototoxicity, neurotoxicity or nephrotoxicity. Despite the activity of satraplatin in mCRPC, survival was not extended in an unselected population included in a Phase III trial. While further development of satraplatin in large Phase III trials is not planned at this time, efforts are ongoing to develop tailored therapy in mCRPC based on excision repair cross-complementing group 1 expression or BRCAness. Moreover, based on potentially better central nervous system penetration due to lipophilicity, evaluation in patients with brain tumors is ongoing. Given the favorable toxicity profile and convenient oral administration, satraplatin may warrant development in settings that preclude cisplatin, for example, underlying renal dysfunction, elderly age and poor performance status.

Platinum-(IV)-derivative satraplatin induced G2/M cell cycle perturbation via p53-p21(waf1/cip1)-independent pathway in human colorectal cancer cells

AIM

Platinum-(IV)-derivative satraplatin represents a new generation of orally available anti-cancer drugs that are under development for the treatment of several cancers. Understanding the mechanisms of cell cycle modulation and apoptosis is necessary to define the mode of action of satraplatin. In this study, we investigate the ability of satraplatin to induce cell cycle perturbation, clonogenicity loss and apoptosis in colorectal cancer (CRC) cells.

METHODS

CRC cells were treated with satraplatin, and the effects of satraplatin on apoptosis and the cell cycle were evaluated by flow cytometry. Western blot analysis was used to investigate the effects of satraplatin on cell cycle and apoptosis-related proteins. RT-qPCR was used to evaluate p53-related mRNA modulation.

RESULTS

Satraplatin induced an accumulation of CRC cells predominantly in the G(2)/M phase. Increased p53 protein expression was observed in the p53 wild-type HCT116 and LoVo cells together with p21(waf1/cip1) protein up-regulation. However, p21(waf1/cip1) protein accumulation was not observed in the p53 mutant HCT15, HT29, and WiDr cells, even when p53 protein expression was compromised, suggesting that the cell cycle perturbation is p53-p21(waf1/cip1) independent. Following a candidate approach, we found an elevated expression of 14-3-3σ protein levels in CRC cells, which was independent of the status of p53, further supporting the role of satraplatin in the perturbation of the G(2)/M cell cycle phase. Moreover, satraplatin treatment induced apoptosis along with Bcl-2 protein down-regulation and abrogated the clonogenic formation of CRC cells in vitro.

CONCLUSION

Collectively, our data suggest that satraplatin induces apoptosis in CRC cells, which is preceded by cell cycle arrest at G(2)/M due to the effect of 14-3-3σ and in a p53-p21(waf1/cip1)-independent manner. Taken together, these findings highlight the potential use of satraplatin for CRC treatment.

The new platinum-based anticancer agent LA-12 induces retinol binding protein 4 in vivo

BACKGROUND

The initial pharmacokinetic study of a new anticancer agent (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum (IV) (LA-12) was complemented by proteomic screening of rat plasma. The objective of the study was to identify new LA-12 target proteins that serve as markers of LA-12 treatment, response and therapy monitoring.

METHODS

Proteomic profiles were measured by surface-enhanced laser desorption-ionization time-of-flight mass spectrometry (SELDI-TOF MS) in 72 samples of rat plasma randomized according to LA-12 dose and time from administration. Correlation of 92 peak clusters with platinum concentration was evaluated using Spearman correlation analysis.

RESULTS

We identified Retinol-binding protein 4 (RBP4) whose level correlated with LA-12 level in treated rats. Similar results were observed in randomly selected patients involved in Phase I clinical trials.

CONCLUSIONS

RBP4 induction is in agreement with known RBP4 regulation by amantadine and cisplatin. Since retinol metabolism is disrupted in many cancers and inversely associates with malignancy, these data identify a potential novel mechanism for the action of LA-12 and other similar anti-cancer drugs.

A phase I study of the oral platinum agent satraplatin in sequential combination with capecitabine in the treatment of patients with advanced solid malignancies

BACKGROUND

The broad spectrum of antitumor activity of both the oral platinum analogue satraplatin (S) and capecitabine (C), along with the advantage of their oral administration, prompted a clinical study aimed to define the maximum tolerated dose (MTD) of the combination.

PATIENTS AND METHODS

Four dose levels of S (mg/m(2)/day) and C (mg/m(2)/day) were evaluated in adult patients with advanced solid tumors: 60/1650, 80/1650, 60/2000, 70/2000; a course consisted of 28 days with sequential administration of S (days 1-5) and C (days 8-21) followed by one week rest.

RESULTS

Thirty-seven patients were treated, 24 in the dose escalation and 13 in the expansion phase; at the MTD, defined at S 70/C 2000, two patients presented dose limiting toxicities: lack of recovery of neutropenia by day 42 and nausea with dose skip of C. Most frequent toxicities were nausea (57%), diarrhea (51%), neutropenia (46%), anorexia, fatigue, vomiting (38% each). Two partial responses were observed in platinum sensitive ovarian cancer and one in prostate cancer.

CONCLUSION

At S 70/C 2000 the combination of sequential S and C is tolerated with manageable toxicities; its evaluation in platinum and fluorouracil sensitive tumor types is worthwhile because of the easier administration and lack of nephro- and neurotoxicity as compared to parent compounds.

Antitumor activity of satraplatin in cisplatin-resistant oral squamous cell carcinoma cells

BACKGROUND

The aim of the current study was to identify the antitumor activity of satraplatin in paired cisplatin (CDDP)-resistant oral squamous cell carcinoma (OSCC) cell line and its parental cell line.

METHODS

CDDP-resistant (KB-R) cells and parental cells (KB) pair were used. Viability was assessed using the MTT and clonogenic assay. Real-time polymerase chain reaction (PCR), glutathione (GSH) assay, and flow cytometric analysis were used for further assessment.

RESULTS

KB-R cells did not show cross-resistance to satraplatin. The expression status of almost all transporters was upregulated in the KB-R cells. There was no difference in the GSH levels between the KB and KB-R cells. Flow cytometric analysis indicated that with satraplatin the G2/M phase was arrested in the KB-R cells. KB-R cells contain enriched side population cells.

CONCLUSION

These data suggested that satraplatin has antitumor activity against the CDDP-resistant OSCC cells. The mechanism of cross-resistance to platinum agents seems to be multifactorial.

A phase 1/1b study of satraplatin (JM-216) in combination with docetaxel in patients with advanced solid tumors and metastatic castrate-resistant prostate cancer

BACKGROUND

Satraplatin is an oral platinum with potential advantages over other platinum agents. This study investigated the combination of satraplatin and docetaxel in a phase 1 study of patients with advanced solid tumor malignancies followed by a phase 1b study in men with chemotherapy naïve metastatic castrate-resistant prostate cancer (CRPC).

METHODS

In this single institution phase 1/1b study, patients received docetaxel on day 1 and satraplatin on days 1-5 of a 21-day cycle ± granulocyte colony stimulating factor (GCSF). For phase 1b, prednisone 10 mg daily was added.

RESULTS

Twenty-nine patients received treatment. Based on 3 dose limiting toxicities (DLT) (grade 4 neutropenia) in 13 patients at dose levels 1 and -1 (docetaxel 60 mg/m(2) plus satraplatin 40 mg/m(2) and docetaxel 60 mg/m(2) plus satraplatin 50 mg/m(2)) GCSF was administered with subsequent cohorts. A dose level of docetaxel 60 mg/m(2) plus satraplatin 50 mg/m(2) with GCSF was the starting dose level for phase 1b. At the highest dose in the phase 1b (docetaxel 75 mg/m(2) plus satraplatin 50 mg/m(2)) there were no DLTs.

CONCLUSION

The combination of satraplatin and docetaxel is feasible in solid tumor malignancies. In advanced malignancies, the recommended phase 2 dose is docetaxel 60 mg/m(2) IV day 1 with satraplatin 40 mg/m(2)/d PO days 1-5, without G-CSF, and Docetaxel 70 mg/m(2) IV day 1 with Satraplatin 50 mg/m(2)/day PO days 1-5, with G-CSF support, repeated in 3-week cycles. For patients with CRPC the recommended phase 2 dose is docetaxel 75 mg/m(2) IV day 1 with satraplatin 50 mg/m(2)/d PO days 1--5, with G-CSF and prednisone 10 mg daily, repeated in 3-week cycles.

The new platinum(IV) derivative LA-12 shows stronger inhibitory effect on Hsp90 function compared to cisplatin

Background

Cisplatin and its derivatives are commonly used anti-cancer drugs. However, cisplatin has clinical limitations including serious side effects and frequent emergence of intrinsic or acquired resistance. Thus, the novel platinum(IV) complex LA-12 represents a promising treatment modality, which shows increased intracellular penetration resulting in improved cytotoxicity in various cancer cell lines, including cisplatin resistant cells.

Results

LA-12 disrupts cellular proliferation regardless of the p53 status in the cells, however the potency of the drug is greatly enhanced by the presence of a functional p53, indicating several mechanisms of action. Similarly to cisplatin, an interaction of LA-12 with molecular chaperone Hsp90 was proposed. Binding of LA-12 to Hsp90 was demonstrated by Hsp90 immunoprecipitation followed by platinum measurement using atomic absorption spectrometry (AAS). An inhibitory effect of LA-12 on Hsp90 chaperoning function was shown by decrease of Hsp90-assisted wild-type p53 binding to p21^WAF1 promoter sequence in vitro and by accelerated ubiqutination and degradation of primarily unfolded mutant p53 proteins in cells exposed to LA-12.

Conclusions

To generalize our findings, LA-12 induced degradation of other Hsp90 client proteins such as Cyclin D1 and estrogen receptor was shown and proved as more efficient in comparison with cisplatin. This newly characterised molecular mechanism of action opens opportunities to design new cancer treatment strategy profitable from unique LA-12 properties, which combine DNA damaging and Hsp90 inhibitory effects.

Satraplatin: leading the new generation of oral platinum agents

BACKGROUND

In recent years, JM-216/satraplatin (GPC Biotech, Inc.) has emerged as a novel oral platinum analogue with a better toxicity profile than cisplatin. Since satraplatin is more hydrophobic than cisplatin or oxaliplatin, it appears to demonstrate efficacy in cisplatin-resistant cell lines. The preclinical and clinical evaluation of satraplatin stimulated this review of the pharmacology and clinical trial data of this agent.

METHODS

A literature review was conducted in the MEDLINE database from 1985 to present using the keywords 'satraplatin' or 'JM-216'. The abstracts regarding satraplatin reported at the 2007 - 2009 American Society of Clinical Oncology meetings were also reviewed.

RESULTS/CONCLUSION

Satraplatin has a favorable toxicity profile, and appears to have clinical activity against a variety of malignancies such as breast, prostate and lung cancer. The oral route of administration and the intermittent schedule makes it very convenient for clinical use. Despite this, a FDA-approved indication has not yet been achieved. The only Phase III trial with satraplatin was conducted in pretreated metastatic castrate-resistant prostate cancer (CRPC), revealing an improvement in progression-free survival but no overall survival benefit. Future development would have to include designing trials in docetaxel-refractory metastatic CRPC, or in other malignancies where cisplatin is of benefit.

Satraplatin for the therapy of castration-resistant prostate cancer

While docetaxel-based chemotherapy improves survival in patients with castration-resistant prostate cancer, all of these patient’s cancers will eventually progress and other active treatment agents are necessary. Satraplatin is a third-generation orally-available platinum analog that demonstrated a 33% reduction in the risk of progression in patients with metastatic castration-resistant prostate cancer following one prior chemotherapy regimen in the large Phase III Satraplatin and Prednisone Against Refractory Cancer (SPARC) trial. Satraplatin also demonstrated beneficial effects on pain and displayed evidence of biological activity with prostate-specific antigen level declines and objective response rates. Satraplatin did not significantly extend survival, although this analysis may have been confounded by post-study therapy. Further development is ongoing with the evaluation of combination regimens containing satraplatin in other solid tumors. In addition, efforts are ongoing to select patients who are more likely to benefit from satraplatin.

New-generation platinum agents for solid tumors

Cisplatin was one of the first chemotherapeutic agents to exhibit broad efficacy in solid tumors and it remains among the most widely used agents in the treatment of cancer. Its introduction inspired great efforts to design similarly effective platinum agents that overcome the three main limitations of cisplatin: toxicity, tumor resistance and poor oral bioavailability. However, 40 years after the initial discovery of cisplatin, only two platinum agents have garnered US FDA approval: carboplatin and oxaliplatin. Although hundreds of promising agents were tested in clinical trials during the 1990s, only oxaliplatin made it past clinical development. For a brief period, the economic cost of these unsuccessful efforts retarded further efforts to develop new agents. However, two exciting platinum agents have been brought to Phase III trials: satraplatin in hormone-refractory prostate cancer and picoplatin in small-cell lung cancer. If successful, they may inspire a new effort to bring better-designed platinum agents to market. This article reviews the clinical development of platinum agents to date and speculates on the role of platinum agents in the near future.

Current status and future prospects for satraplatin, an oral platinum analogue

Platinum drugs are major chemotherapeutic agents that are used alone or in combination with other systemic agents and/or radiation therapy in the management of many human malignancies. All three platinum drugs approved by the Food and Drug Administration, cisplatin, carboplatin, and oxaliplatin, are administrated intravenously. Satraplatin is the first orally administered platinum drug under active clinical investigation. Satraplatin and its major metabolite, JM118, have shown antineoplastic activity in in vitro, in vivo, and in clinical settings. Use of satraplatin as an alternative platinum cytotoxic agent is particularly attractive because of the convenience of administration, milder toxicity profile, lack of cross-resistance with cisplatin, theoretical advantage as a radiosensitizer, and activity in cancers historically nonresponsive to platinum drugs. The most mature clinical data for satraplatin come from the recently completed phase III trial that investigated the efficacy of satraplatin and prednisone on hormone-refractory prostate cancer patients who had failed a course of other chemotherapy agents. Preliminary reports show that the combination is statistically superior to placebo and prednisone in multiple end points, including progression-free survival, prostate-specific antigen response, objective tumor response, pain response, and duration of pain response. The difference in overall survival, however, did not reach statistical significance.

Broadening the clinical use of platinum drug-based chemotherapy with new analogues. Satraplatin and picoplatin

The three platinum-containing drugs that have been thus far approved by the FDA - cisplatin, carboplatin and oxaliplatin - have had a significant effect in the treatment of patients with some malignancies such as testicular, ovarian and colorectal cancer. However, much more remains to be achieved to widen the therapeutic use of this important class of drug, either via further analogue development or by judicious use of combining the existing drugs with new molecularly targeted agents. Two analogues arising from an academic (Institute of Cancer Research)/pharmaceutical (Johnson Matthey/AnorMed) collaboration - satraplatin (JM-216) and picoplatin (JM-/AMD-473) - have recently shown promising clinical activity; satraplatin (an orally available drug) in hormone-refractory prostate cancer and picoplatin in small-cell lung cancer. There have also been advances in delivery vehicles for platinum drugs (e.g., the diaminocyclohexane [DACH]-based AP-5346 and aroplatin/liposomal cis-bis-neodecanoato-trans-(R,R)-1,2-diaminocyclohexane platinum (II) [L-NDDP] are in early clinical development). Platinum-based drugs have also been successfully combined with molecularly targeted drugs (e.g., the recent approval of the vascular endothelial growth factor monoclonal antibody bevacizumab with carboplatin and paclitaxel in patients with NSCLC).

Preclinical antitumor activity of the oral platinum analog satraplatin

PURPOSE

Satraplatin is an orally available platinum analog. The purpose of this study was to better characterize satraplatin's preclinical antitumor efficacy in a variety of sensitive and resistant human tumor cell lines and in a prostate cancer xenograft model and to evaluate the effect of satraplatin on PSA expression and/or secretion in a prostate cancer cell line.

METHODS

Satraplatin and its primary metabolite JM-118 were preclinically tested for their cytotoxic activity in a range of cancer cells including: human prostate, those forming the NCI drug screening panel, and those resistant to anti-cancer drugs. Also, the antiproliferative efficacy of satraplatin was tested in vivo in a human prostate cancer model. The effect of satraplatin and JM-118 on PSA transcription was measured by quantitative real time PCR.

RESULTS

Satraplatin and JM-118 inhibited in vitro and in vivo the growth of prostate cancer cells in a dose-dependent fashion. The IC50 cytotoxicity values for satraplatin ranged from 1 to 3 microM for androgen-insensitive cells and was 11 microM for the androgen-sensitive cell line. Interestingly, JM-118 was up to 16-fold more potent than satraplatin. Oral administration of satraplatin to nude mouse PC-3 xenograft models inhibited the growth of these human tumors. Satraplatin had no direct effect on PSA transcription and the observed decrease in secreted PSA correlated with a decrease in cell number. When evaluated in the NCI drug-screening panel, satraplatin was most active in leukemia and small cell lung cancer cell lines. Both satraplatin and JM-118 were tested on cells resistant to chemotherapeutic agents. Satraplatin and JM-118 were equally active in the cisplatin-resistant A129cp80 ovarian carcinoma cell line, with activity comparable to that observed in the parent line. Neither expression of MDR1, BCRP, MRP1, nor altered tubulin or topoisomerase I were found to mediate resistance to satraplatin or JM-118. Although these resistance mechanisms contribute to drug resistance for a number of chemotherapeutics, they do not appear to play a role in satraplatin resistance.

CONCLUSIONS

These results demonstrate that satraplatin and JM-118 have preclinical antitumor activity in human prostate cancer and other tumor types as well, including several cell lines displaying drug resistance to cisplatin, docetaxel and mitoxantrone. In addition, the results suggest that PSA should be further evaluated as a relevant marker of clinical response in patients with prostate cancer treated with satraplatin.

Satraplatin in Hormone-Refractory Prostate Cancer and Other Tumour Types

Satraplatin is the first orally administered platinum drug to be evaluated in the clinic. Oral satraplatin plus prednisone improved progression free survival significantly relative to prednisone alone in patients with hormone-refractory prostate cancer in a randomised study. Furthermore, single-agent satraplatin has demonstrated activity in ovarian cancer and small cell lung cancer similar to that observed with single-agent cisplatin or carboplatin. In >600 treated patients, satraplatin was generally well tolerated and the most common adverse event was non-cumulative myelosuppression.

Satraplatin: an orally available platinum analog for the treatment of cancer

Satraplatin is a novel, orally bioavailable, platinum anticancer drug. Platinum analogs form the mainstay of treatment for a number of cancers, including lung, ovarian, colorectal and head and neck cancer. A disadvantage of the currently marketed platinum analogs is that they must all be administered via intravenous infusion. In addition, their utility is often limited by toxicity, particularly neurotoxicity, ototoxicity and renal toxicity. Satraplatin has preclinical antitumor activity comparable with that of cisplatin and, clinically, has a more manageable side-effect profile. Satraplatin is active in lung, ovarian and prostate cancer, and appears to have good efficacy in combination with radiation for lung and head and neck cancer. Preclinical data suggest it may also be effective for the treatment of certain cisplatin-refractory tumors. A large, randomized Phase III trial is currently evaluating satraplatin in combination with prednisone for the treatment of patients with hormone-refractory prostate cancer whose disease has progressed following prior systemic therapy. Positive results from this trial would support regulatory approval for satraplatin for this indication. The availability of an active oral platinum agent, such as satraplatin, with few of the serious toxicities associated with traditional intravenous platinum compounds makes satraplatin an alternative to other platinum agents and a new treatment option in the oncologist's armamentarium.

Efficient palliation in patients with small-cell lung cancer by a combination of paclitaxel, etoposide and carboplatin: quality of life and 6-years'-follow-up results from a randomised phase III trial

PURPOSE

Based on the promising activity of paclitaxel in small-cell lung cancer (SCLC) we conducted a randomized phase III trial to evaluate whether a combination of paclitaxel, carboplatin and etoposide phosphate (TEC) improves survival and time to progression as well as tolerability and quality of life (QoL) compared to a regimen of carboplatin, etoposide phosphate and vincristine (CEV) in SCLC patients.

PATIENTS AND METHODS

Six hundred and fourteen patients with stages I-IV SCLC were randomly assigned between January 1998 and December 1999 to both treatment arms. All patients were evaluated for response rate, survival, side effects and quality of life with overall survival (OS) serving as primary endpoint. A final analysis was done after a six-year follow-up. Survival curves were estimated using Kaplan-Meier curves and tested with the log-rank test. Quality of life data were assessed in using the EORTC QLQ-C30 questionnaire and evaluated by calculating and comparing the mean scores as well as applying longitudinal techniques.

RESULTS

Six hundred and eight patients were evaluable for efficacy and toxicity. The long-term follow-up confirms the significant survival benefit for the paclitaxel, etoposide, carboplatin (TEC) regimen with a median OS of 12.5 months compared to 11.7 months for the CEV arm (HR, 1.21; 95% CI, 1.02-1.43; P=.030). The 5-year survival rates were 14% for the experimental versus 6 % for the CEV arm. Significant survival prolongation was also observed in the subgroup of patients with stage IV disease (HR, 1.27; 95% CI, 1.00-1.60; P=.047). The previously reported clinical benefit in form of an overall reduction of grade 3/4 toxicity was backed by the results of the comprehensive QoL analysis we report hereby. TEC significantly improves the relevant QoL parameters like global overall QoL or physical functioning.

CONCLUSION

When administered in combination with etoposide and carboplatin, paclitaxel is able to offer in SCLC patients with extensive disease a survival benefit without additional toxicities, but with gains in patient-reported quality of life. In terms of efficient palliative care, TEC might be seen as an alternative to standard cisplatin plus etoposide in patients requesting a powerful palliative regimen not compromising any survival benefit.

Safety profile of platinum-based chemotherapy in the treatment of advanced non-small cell lung cancer in elderly patients

Non-small cell lung cancer (NSCLC) may be considered typical of advanced age. More than 50% of NSCLC patients are diagnosed at > 65 years of age and approximately one-third of all patients are > 70 years of age. Elderly patients tolerate chemotherapy poorly compared with their younger counterpart because of the progressive reduction of organ function and comorbidities related to age. For this reason, these patients are often not considered eligible for aggressive platinum-based chemotherapy, the standard medical treatment for advanced NSCLC. In clinical practice, single-agent chemotherapy should remain the standard treatment. Feasibility of platinum-based chemotherapy remains an open issue and has to be proven prospectively. Moreover, a multidimensional geriatric assessment for individualised treatment choice in NSCLC elderly patients is mandatory. This review focuses on the currently-available evidences for the treatment of elderly patients affected by advanced NSCLC with regards to the role and safety of platinum-based chemotherapy.

Satraplatin activation by haemoglobin, cytochrome C and liver microsomes in vitro

BACKGROUND

Satraplatin is thought to require reduction to a reactive Pt(II) complex (JM118) before exerting chemotherapeutic activity. In this study, we investigated the role of heme proteins in this reductive activation of satraplatin.

METHODS

Satraplatin was incubated in solution with heme proteins and liver microsomes. The oxidation state of heme iron was monitored by visible absorption spectrometry. Satraplatin and JM118 were detected using a sensitive and specific HPLC-ICPMS assay.

RESULTS

Satraplatin was stable in solutions containing haemoglobin, cytochrome c, glutathione, liver microsomes or NADH alone. However, in solutions containing haemoglobin plus NADH, satraplatin disappeared with a half-life of 35.8 mins. Under these conditions, satraplatin was reduced to JM118 and haemoglobin was oxidised to methaemoglobin. The reaction between haemoglobin and satraplatin was inhibited by carbon monoxide or by cooling the reaction solution. Cytochrome c and liver microsomes also reduced satraplatin to JM118 in a manner that depended upon the presence of NADH and was inhibited by carbon monoxide.

CONCLUSION

This study has identified a mechanism of satraplatin activation involving metal-containing redox proteins and the transfer of electrons to the Pt(IV) drug from protein-complexed metal ions. Heme proteins may act by this mechanism as reducing agents for the activation of satraplatin in vivo.

New-generation platinum drugs in the treatment of cisplatin-resistant cancers

Platinum drugs with altered stable ligands, such as oxaliplatin and satraplatin, produce a different DNA-adduct profile to cisplatin. This results in a distinct therapeutic profile, and clinical trials with these agents demonstrate significant anticancer activity in diseases with inherent or acquired resistance to cisplatin, such as colorectal and prostate cancers as well as previously treated ovarian and germ-cell cancer. An alternative approach to increasing the efficacy associated with platinum therapy is to enhance tumour delivery by coupling platinum drugs with a polymer or encapsulating the agent in a liposome. The early clinical trials of these novel delivery formulations are promising but, as yet, have not confirmed that the delivery of platinum to the tumour cell DNA is increased.

Pharmacokinetics and tissue distribution of platinum in rats following single and multiple oral doses of LA-12 [(OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV)]

The pharmacokinetics of total and free plasma platinum (Pt) and Pt tissue distribution were investigated in rats after oral administration of (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) (LA-12). Plasma and ultrafiltrate were sampled until 48 h and tissue samples were taken at 24 and 48 h after single doses of 38.6 or 540 mg LA-12/kg, and after once-a-day dosing of 4.3 or 38.6 mg kg(-1) LA-12 over 14 consecutive days. Total plasma Pt concentrations increased less than proportionally to the 14-fold increase in the single dose. The mean C(max) values of 1.5 and 6.3 mg L(-1) were observed at 0.5 and 1 h, respectively, and the mean AUC values achieved were 29 and 144 mg h L(-1). The highest tissue Pt concentrations were found in the liver and kidneys. Platinum was undetectable in the brain while in other tissues (muscle, skin, heart, lungs), the concentrations were lower (after single dose) or similar (after multiple doses) when compared to the plasma C(max) values. Plasma Pt concentrations after once-a-day dosing of 38.6 mg kg(-1) were two- to three-fold less than that after a single dose while Pt concentrations in various tissues rose two- to four-fold. Accumulation of Pt was even higher in the kidneys (seven-fold) and spleen (nine-fold). After once-a-day dosing, tissue Pt levels increased proportionally with the dose within the range from 4.3 to 38.6 mg kg(-1). At the same time, the increase in total plasma Pt concentrations was 40% less than proportional. Concentrations of Pt in the plasma ultrafiltrate decreased rapidly with the initial half-life of 1 h.

Tumour-inhibiting platinum complexes--state of the art and future perspectives

Thirty years after the onset of the first clinical studies with cisplatin, the development of antineoplastic platinum drugs continues to be a productive field of research. This article reviews the current preclinical and clinical status, including a discussion of the molecular basis for the activity of the parent drug cisplatin and platinum drugs of the second and third generation, in particular their interaction with DNA. Further emphasis is laid on the development of third generation platinum drugs with activity in cisplatin-resistant tumours, particularly on chelates containing 1,2-diaminocyclohexane (DACH) and on the promising and more recently evolving field of non-classic ( trans- and multinuclear) platinum complexes. The development of oral platinum drugs and drug targeting strategies using liposomes, polymers or low-molecular-weight carriers in order to improve the therapeutic index of platinum chemotherapy are also covered.

JM216-, JM118-, and cisplatin-induced cytotoxicity in relation to platinum-DNA adduct formation, glutathione levels and p53 status in human tumour cell lines with different sensitivities to cisplatin

The aim of this study is to establish anti-tumour potency of the new oral platinum drug JM216 and its metabolite JM118 in relation to the platinum (Pt)-DNA adduct formation, glutathione (GSH)-levels, and p53 status in human cancer cell lines with different sensitivities to cisplatin (CDDP). These parameters were studied in the CDDP sensitive human germ cell cancer cell line Tera and the small-cell lung cancer cell line GLC4 and their sublines with in vitro acquired CDDP resistance, Tera-CP and GLC4-CDDP, in a human ovarian cancer cell line transfected with mutant p53 (A2780/mt273) and with an empty vector as control (A2780/cmv), and in the intrinsic CDDP resistant human non-small-cell lung cancer cell line SW1573/S1 and colon carcinoma cell line Caco-2. Cytotoxicity was tested with the microculture tetrazolium (MTT)-assay. Pt-DNA adduct levels were assessed immunocytochemically. Quantitative analysis was performed by double fluorescence video microscopy. Results were correlated with GSH levels and p53 status of the cell lines. This study showed that both JM216 and JM118 can partially circumvent intrinsic and acquired resistance to CDDP. Drug-induced cytotoxicity only correlated negatively with GSH levels for JM216 and CDDP in the tested unselected cell lines. At equimolar basis, JM216 induced lower levels of Pt-DNA adducts in the various cell lines than JM118 and CDDP, whereas the JM118-induced amount and pattern of Pt-DNA adducts was comparable to CDDP. No difference in initial Pt-DNA adducts levels was observed between cell lines sensitive, acquired or intrinsic resistant to CDDP suggesting a Pt-resistance mechanism based on tolerance or increased repair, rather than decreased initial Pt-DNA adduct formation.

A phase I trial of the oral platinum analogue JM216 with concomitant radiotherapy in advanced malignancies of the chest

JM216 is an orally administered platinum analogue. We undertook this study to determine the maximally tolerated dose (MTD) of JM216 when administered with concomitant radiotherapy to the chest (200 cGy daily, 5 x/week) in patients with locoregionally advanced non-small cell lung (NSCLC) or esophageal cancer. Patients were excluded for inadequate bone marrow reserve, prior radiotherapy to the primary tumor or previous treatment with platinum drugs. A dose-limiting toxicity (DLT) was defined using the National Cancer Institute (NCI) Common Toxicity Criteria (CTC) and consisted of grade > or = 2 renal, hepatic, cardiac, or pulmonary toxicity or grade > or = 3 hematologic, neurological, or gastrointestinal toxicity. A total of 23 patients were registered; two never received treatment and are excluded from analyses. Six patients were treated at a dose of 30 mg/m2/day for 5 days with two grade 2 DLT's: cough (1 pt) and elevated trans-aminases (1 pt). Seven evaluable patients were treated at 60 mg/m2/day and seven experienced grade 3 or 4 toxicity, five related to myelosuppression. The dose was then reduced to 45 mg/m2/d. Eight patients were evaluable for toxicity, of which 5 experienced DLT: myelosuppression (3 pts), esophagitis (2 pts), dyspnea (1 pt), and elevated creatinine (1 pt). Fourteen patients were evaluable for efficacy, of which 6 had an objective response, including one complete response. The recommended phase II dose of JM216 with concurrent radiation therapy is 30 mg/m2/d for 5 days. The major DLT is myelosuppression with only limited increased toxicity within the field of radiation. This conceivably may limit the use of JM216 as a radiation sensitizer.

Phase I study of JM-216 (an oral platinum analogue) in combination with paclitaxel in patients with advanced malignancies

This phase I study was conducted to determine the dose limiting toxicity, maximum tolerated doses, and recommended phase II doses of the combination of JM-216 and paclitaxel. Patients received paclitaxel intravenously over one hour on day 1 of each cycle. Oral JM-216 was administered on days 1-5 starting after the paclitaxel infusion. Cycles were repeated every 21 days. Patients were accrued at nine different dosing combinations. JM-216 doses ranged from 10-80 mg/m2/day and were combined with paclitaxel doses of 150, 175, or 200 mg/m2. Forty-three patients were treated with 146 cycles of therapy. Dose-limiting toxicity, consisting of febrile neutropenia and grade 3 thrombocytopenia, was encountered in 2 patients at the seventh dose level (JM-216 80 mg/m2/day + paclitaxel 175 mg/m2). Two intermediate dose levels were explored. The first level (JM-216 70 mg/m2/day + paclitaxel 175 mg/m2) produced dose-limiting thrombocytopenia in 1 of 6 patients. However, two additional patients also demonstrated delayed recovery from thrombocytopenia following treatment. As a result, a second intermediate dose level (JM-216 60 mg/m2/day + paclitaxel 200 mg/m2) was filled with six patients. No dose-limiting toxicities were reported in any patients at this dose level. The combination of oral JM-216 and paclitaxel is well-tolerated with minimal non-hematologic and reversible hematologic toxicity. The recommended dose for phase II study is JM-216 60 mg/m2/day for 5 days and paclitaxel 200 mg/m2 on day 1 repeated every 21 days. Higher doses of JM-216 are associated with more severe thrombocytopenia and delayed hematologic recovery resulting in subsequent dosing delays.

Management of small cell cancer of the lung

Small cell lung cancer (SCLC) accounts for 20% to 25% of bronchogenic carcinoma cases. Combination chemotherapy offers the best chance for improved survival. Cisplatin plus etoposide appears to be the most reasonable choice for first line therapy. Increasing dose intensity, although sometimes associated with higher response rates, does not appear to significantly improve survival. Concurrent thoracic radiotherapy administered early in the course of chemotherapy confers a survival advantage over chemotherapy alone in limited-stage SCLC. Prophylactic cranial irradiation reduces central nervous system recurrences with minimal long-term sequelae and appears to improve survival. Several new cytotoxic agents are active in SCLC. These include gemcitabine, paclitaxel, docetaxel, topotecan, irinotecan, and JM216. Novel approaches being investigated include antibodies to factors expressed by SCLC cells and agents targeting angiogenesis, cell cycle regulation, and cell-signaling pathways.

An update on satraplatin: the first orally available platinum anticancer drug

This update focuses on the clinical development of the first orally available platinum-containing anticancer drug, satraplatin (JM216, BMS 182751, BMY 45594). Satraplatin was selected for clinical study on the basis of possessing several promising preclinical features the first of which is it's potent in vitro growth inhibitory properties against several tumour types (mean IC(50) approximately 1 microM). Secondly, it possesses in vivo oral antitumour activity against a variety of murine and human sc. tumour models, broadly comparable to the level of activity obtainable with parenterally administered cisplatin or carboplatin. Lastly, it has a relatively mild toxicity profile with myelosuppression being dose-limiting. Satraplatin entered clinical trials in 1992 and is now undergoing Phase III evaluation. Non-linear pharmacokinetics, probably due to saturable absorption, was observed when the drug was administered as a bolus every 3 - 4 weeks. Subsequent Phase II trials have used a daily schedule for five consecutive days, at doses of around 120 mg/m(2)/day. The drug produced relatively mild side effects with controllable nausea and vomiting and, as predicted from the mouse studies, myelosuppression as the dose-limiting effect (neutropoenia and thrombocytopoenia). Combination trials are also ongoing with paclitaxel or radiation. The metabolism of satraplatin is complex, with at least six biotransformation products observed in the plasma of patients. The platinum(II) complex JM118 is the main metabolite, three other minor metabolites have been identified, there is no detectable parent drug. Tumour responses have been recorded, particularly in patients with small cell lung cancer and hormone refractory prostate cancer. These clinical studies with satraplatin indicate that oral platinum-based chemotherapy is feasible.