To define the maximum tolerated dose, clinical toxicities, and pharmacodynamics of bevacizumab, everolimus and panobinostat (LBH-589) when administered in combination in patients with advanced solid tumor malignancies.
Subjects received 10 mg of panobinostat three times weekly, 5 or 10 mg everolimus daily and bevacizumab at 10 mg/kg every two weeks. Dose limiting toxicities (DLTs) were assessed in cycle 1; toxicity evaluation was closely monitored throughout treatment. Treatment continued until disease progression or undesirable toxicity. Protein acetylation was assessed in peripheral blood mononuclear cells (PBMC) both at baseline and on-treatment.
Twelve subjects were evaluable for toxicity and nine subjects for response. DLTs in cohort 1 included grade 2 esophagitis and grade 3 oral mucositis; DLTs in cohort -1 were grade 2 ventricular arrhythmia and grade 2 intolerable skin rash. Common adverse events were diarrhea (50%), headache (33%), mucositis/stomatitis (25%), hyperlipidemia (25%), and thrombocytopenia (25%). There was 1 partial response; an additional 2 subjects had stable disease as best response. No consistent changes in protein acetylation in PBMC were observed in samples available from eight patients on treatment compared to baseline.
Bevacizumab, everolimus, and panobinostat in combination at the lowest proposed doses did not have an acceptable safety and tolerability profile, and did not consistently inhibit HDAC activity; therefore we do not recommend further evaluation.
Bevacizumab; Everolimus; Panobinostat; Phase I; Advanced Cancer
To characterize the cellular action mechanism of Debio 0507, we compared the major DNA adducts formed by Debio 0507- and oxaliplatin-treated HCT116 human colon carcinoma cells by a combination of inductively coupled plasma mass spectrometry (ICP-MS) and ultra-performance liquid chromatography mass spectrometry (UPLC-MS/MS).
HCT116 cells were treated with IC50 doses of Debio 0507 or oxaliplatin for 3 days. Total cellular Pt–DNA adducts were determined by ICP-MS. The DNA was digested, and the major Pt–DNA adducts formed by both drugs were characterized by UPLC/MS/MS essentially as described previously for cisplatin (Baskerville-Abraham et al. in Chem Res Toxicol 22:905–912, 2009).
The Pt level/deoxynucleotide was 7.4/104 for DNA from Debio 0507-treated cells and 5.5/104 for oxaliplatin-treated cells following a 3-day treatment at the IC50 for each drug. UPLC-MS/MS in the positive ion mode confirmed the major Pt–DNA adducts formed by both drugs were dach-Pt-d(GpG) (904.2 m/z → 610 m/z and 904.2 m/z → 459 m/z) and dach-Pt-d(ApG) (888.2 m/z → 594 m/z and 888.2 m/z → 459 m/z).
These data show that the major DNA adducts formed by Debio 0507 are the dach-Pt-d(GpG) and dach-Pt-d(ApG) adducts and at equitoxic doses Debio 0507 and oxaliplatin form similar levels of dach-Pt-d(GpG) and dach-Pt-d(ApG) adducts. This suggests that the action mechanisms of Debio 0507 and oxaliplatin are similar at a cellular level.
Debio 0507; Oxaliplatin; DNA adducts; LC/MS; UPLC/MS/MS
The 5-substituted pyrrolo[2,3-d]pyrimidine antifolate pemetrexed (Pmx) is an active agent for malignant pleural mesothelioma (MPM). Pmx is transported into MPM cells by the reduced folate carrier (RFC) and proton-coupled folate transporter (PCFT). We tested the notion that a novel 6-substituted pyrrolo[2,3-d]pyrimidine thienoyl antifolate (compound 2) might be an effective treatment for MPM, reflecting its highly selective membrane transport by PCFT over RFC. Compound 2 selectively inhibited proliferation of a HeLa subline expressing exclusively PCFT (R1-11-PCFT4) over an isogenic subline expressing only RFC (R1-11-RFC6). By outgrowth, H2452 human MPM cells were highly sensitive to the inhibitory effects of compound 2. By colony-forming assays, following an intermittent (24 h) drug exposure, 2 was cytotoxic. Cytotoxic activity by 2 was due to potent inhibition of glycinamide ribonucleotide formyltransferase (GARFTase) in de novo purine biosynthesis, as confirmed by nucleoside protection and in situ GARFTase assays with [14C]glycine. Assays with [3H]compound 2 and R1-11-PCFT4 or R1-11-RFC6 cells directly confirmed selective membrane transport by PCFT over RFC. PCFT transport was also confirmed for H2452 cells. In R1-11-PCFT4 and H2452 cells, [3H]compound 2 was metabolized to polyglutamates. Potent in vivo efficacy was confirmed toward early- and upstage H2452 xenografts in severe combined immunodeficient mice administered intravenous compound 2. Our results demonstrate potent antitumor efficacy of compound 2 toward H2452 MPM in vitro and in vivo, reflecting its efficient membrane transport by PCFT over RFC, synthesis of polyglutamates, and inhibition of GARFTase. Selectivity for non-RFC cellular uptake processes by novel tumor-targeted antifolates such as compound 2 presents an exciting new opportunity for treating solid tumors.
proton-coupled folate transporter; mesothelioma; folate; antifolate; pemetrexed
In some reports, 5-fluorouracil has been associated with modest activity in patients with neuroendocrine tumors. Pemetrexed is a multitargeted antifolate with activity in tumor types not significantly responsive to other antifolates. We evaluated the efficacy of pemetrexed in a phase II study of patients with advanced neuroendocrine tumors.
Patients with metastatic neuroendocrine tumors (excluding small-cell carcinoma) were treated with pemetrexed administered intravenously at a dose of 500 mg/m2 every 21 days. To reduce potential toxicity, patients also received folic acid, vitamin B12 supplementation, and periinfusional treatment with dexamethasone. Patients were followed for response, toxicity, and survival.
The study was designed with a total accrual goal of 32 patients. Due to lack of radiographic responses in patients during the study period, accrual was terminated at 17. However, one patient achieved a delayed partial response following discontinuation of pemetrexed. Ten patients were evaluable for biochemical response; five (50%) experienced >50% decrease in plasma chromogranin A. Among the 17 patients, 5 (29%) discontinued therapy due to treatment-related toxicity. The median overall survival was 12.1 months.
Pemetrexed does not appear to have significant antitumor activity in patients with advanced neuroendocrine tumors. The limited antitumor activity and potential toxicity associated with pemetrexed mirrors experience with the majority of other cytotoxic agents in patients with neuroendocrine tumors. Investigation of novel, molecularly targeted agents may offer more promise in this disease.
Pemetrexed; Neuroendocrine tumor; Carcinoid tumor; Pancreatic neuroendocrine tumor
Tolerability, pharmacokinetics (PK), pharmacodynamics, and antitumor activity of carfilzomib, a selective proteasome inhibitor, administered twice weekly by 2–10-min intravenous (IV) infusion on days 1, 2, 8, 9, 15, and 16 in 28-day cycles, were assessed in patients with advanced solid tumors in this phase I/II study.
Adult patients with solid tumors progressing after ≥1 prior therapies were enrolled. The dose was 20 mg/m2 in week 1 of cycle 1 and 20, 27, or 36 mg/m2 thereafter. The maximum tolerated dose or protocol-defined maximum planned dose (MPD) identified during dose escalation was administered to an expansion cohort and to patients with small cell lung, non-small cell lung, ovarian, and renal cancer in phase II tumor-specific cohorts.
Fourteen patients received carfilzomib during dose escalation. The single dose-limiting toxicity at 20/36 mg/m2 was grade 3 fatigue, establishing the MPD as the expansion and phase II dose. Sixty-five additional patients received carfilzomib at the MPD. Adverse events included fatigue, nausea, anorexia, and dyspnea. Carfilzomib PK was dose proportional with a half-life <1 h. All doses resulted in at least 80 % proteasome inhibition in blood. Partial responses occurred in two patients in phase I, with 21.5 % stable disease after four cycles in evaluable patients in the expansion and phase II cohorts.
Carfilzomib 20/36 mg/m2 was well tolerated when administered twice weekly by 2–10-min IV infusion. At this dose and infusion rate, carfilzomib inhibited the proteasome in blood but demonstrated limited antitumor activity in patients with advanced solid tumors.
Proteasome inhibitor; Carfilzomib; Solid tumors; Pharmacokinetics; Pharmacodynamics
To assess the clinical efficacy of targeted arterial perfusion of verapamil and chemotherapeutic agents in the interventional therapy of lung cancer.
Forty patients with advanced lung cancer underwent treatment with targeted arterial perfusion of verapamil and chemotherapeutic agents using Seldinger technique. Interventional therapy was performed once a month, and each subject received interventional treatment for 2 or more cycles. The therapeutic efficacy was evaluated 2 months post-treatment.
Out of 40 patients with advanced lung cancer, 5 cases achieved complete remission (CR) and 29 cases achieved partial remission (PR), with a total effectiveness (CR + PR) rate of 85 %. Besides, 32 cases achieved significantly alleviated clinical symptoms, and 29 cases had decreased clinical tumor stage. All subjects had stable karnofsky performance status score and body weight. Among the 40 patients, 13 cases had leucopenia, 10 cases had gastrointestinal reactions, 3 cases presented with elevated alanine aminotransferase/aspartate aminotransferase ratio, and 3 cases had fever. However, all these side effects relieved quickly. No elevation of BUN/Cr ratio and allergic reactions was observed. No significant changes in cardiac function and electrocardiogram were noticed after the treatment.
Targeted arterial perfusion of verapamil and chemotherapeutic drugs can improve the clinical symptoms of patients with advanced lung cancer and increase the efficacy of chemotherapeutic agents, thereby providing an opportunity for radiotherapy or surgical treatment for advanced lung cancer.
Verapamil; Advanced lung cancer; Arterial perfusion; Multidrug resistance
To study a commonly used Astragalus-based herbal formula previously found effective in non-small cell lung cancer (NSCLC) on the pharmacokinetics of docetaxel in patients with NSCLC.
Patients with advanced NSCLC who progressed after prior platinum-containing chemotherapy were accrued and received docetaxel at 35 mg/m2 for 3 weeks followed by 1 week of rest. At 4 days prior to the second dosing, Jinfukang was given orally. Pharmacokinetic studies of initial-dose docetaxel (in the absence of Jinfukang) and the third dose (in the presence of Jinfukang) were compared.
Of the 24 patients enrolled, 21 started Jinfukang and docetaxel. Jinfukang had no significant impact on the pharmacokinetics of docetaxel. Median time to progression or withdrawal from treatment was 7 weeks. Twelve patients were removed from study for progression of disease; nine patients withdrew.
Jinfukang did not alter the pharmacokinetics of docetaxel nor appear to affect survival in this study.
Lung cancer; Chemotherapy; Docetaxel; Botanicals; Astragalus
Dinaciclib inhibits cyclin-dependent kinases 1, 2, 5, and 9 with a better therapeutic index than flavopiridol in preclinical studies. This study assessed the activity of dinaciclib in acute leukemia both in the clinic and in vitro.
Adults with relapsed/refractory acute myeloid leukemia (n = 14) and acute lymphoid leukemia (n = 6) were treated with dinaciclib 50 mg/m2 given as a 2-h infusion every 21 days.
Most patients had dramatic but transient reduction in circulating blasts; however, no remissions were achieved on this schedule. The most common toxicities were gastrointestinal, fatigue, transaminitis, and clinical and laboratory manifestations of tumor lysis syndrome, including one patient who died of acute renal failure. Dinaciclib pharmacokinetics showed rapid (2 h) achievement of maximum concentration and a short elimination/distribution phase. Pharmacodynamic studies demonstrated in vivo inhibition of Mcl-1 expression and induction of PARP cleavage in patients’ peripheral blood mononuclear cells 4 h after dinaciclib infusion, but the effects were lost by 24 h and did not correlate with clinical outcome. Correlative in vitro studies showed that prolonged exposures to dinaciclib, at clinically attainable concentrations, result in improved leukemia cell kill.
While dinaciclib given as a 2-h bolus did not exhibit durable clinical activity, pharmacokinetic and pharmacodynamic data support the exploration of prolonged infusion schedules in future trials in patients with acute leukemias.
Electronic supplementary material
The online version of this article (doi:10.1007/s00280-013-2249-z) contains supplementary material, which is available to authorized users.
Dinaciclib; Acute leukemia; Cyclin-dependent kinase; CDK inhibitor; Mcl-1
Tumor hypoxia reduces the efficacy of radiation and chemotherapy as well as altering gene expression that promotes cell survival and metastasis. The growth factor receptor, Her2/neu, is overexpressed in 25–30% of breast tumors. Tumors that are Her2+ may have an altered state of oxygenation, relative to Her2−tumors, due to differences in tumor growth rate and angiogenesis.
Her2 blockade was accomplished using an antibody to the receptor (trastuzumab; Herceptin). This study examined the effects of Her2 blockade on tumor angiogenesis, vascular architecture, and hypoxia in Her2+ and Her2− MCF7 xenograft tumors.
Treatment with trastuzumab in Her2+ tumors significantly improved tumor oxygenation, increased microvessel density, and improved vascular architecture compared with the control-treated Her2+ tumors. The Her2+ xenografts treated with trastuzumab also demonstrated decreased proliferation indices when compared with control-treated xenografts. These results indicate that Her2 blockade can improve tumor oxygenation by decreasing oxygen consumption (reducing tumor cell proliferation and inducing necrosis) and increasing oxygen delivery (vascular density and architecture).
These results support the use of trastuzumab as an adjunct in the treatment of breast tumors with chemotherapy or radiotherapy, as improvements in tumor oxygenation should translate into improved treatment response.
Her2/neu; Angiogenesis; Tumor hypoxia; Breast cancer
The safety, tolerability, and pharmacokinetic (PK) interactions of MK-0646 in combination with cetuximab and irinotecan were investigated in Japanese patients with advanced colorectal cancer.
Twenty patients were treated in the following study arms in combination with cetuximab and irinotecan: A [MK-0646 (10 mg/kg) weekly starting on Day 22], B [MK-0646 (15 mg/kg) on Day 8, followed by 7.5 mg/kg every 2 weeks], or C [MK-0646 (10 mg/kg) on Day 1 and weekly starting on Day 22]. Dose limiting toxicities (DLTs) were evaluated during a prespecified 4-week period in arms A and B. Full PK sampling was performed to evaluate the PK interactions.
One of the 6 evaluable patients in arm A developed a DLT (grade 3 hyperglycemia); no DLTs occurred in the 6 patients in arm B. Common treatment-related adverse events included leukopenia, neutropenia, dermatitis acneiform, paronychia, nausea, stomatitis, diarrhea, and decreased appetite. The co-administration of cetuximab and irinotecan with MK-0646 increased the MK-0646 AUC0–168h by 25 %, with MK-0646 accumulation from the previous dose contributing to the observed increase. The co-administration of MK-0646 with cetuximab and irinotecan did not affect the PK of cetuximab and irinotecan, but reduced the Cmax (from 16.8 to 13.0 ng/mL) and the AUC0–24h (by 13 %) of SN-38, the active metabolite of irinotecan.
The triple combination of MK-0646, cetuximab, and irinotecan was well tolerated in Japanese patients with advanced colorectal cancer. These results indicate a minimal potential for PK interactions between MK-0646 and cetuximab and between MK-0646 and irinotecan/SN-38.
Colorectal cancer; MK-0646; Anti-IGF-1R antibody; Pharmacokinetic interactions; Phase I study
Systemically administered fludarabine phosphate (F-araAMP) slows growth of human tumor xenografts that express E. coli purine nucleoside phosphorylase (PNP). However, this treatment has been limited by the amount of F-araAMP that can be administered in vivo. The current study was designed to 1) determine whether efficacy of this overall strategy could be improved by intratumoral (IT) administration of F-araAMP, 2) test enhancement of the approach with external beam radiation, and 3) optimize recombinant adenovirus as a means to augment PNP delivery and bystander killing in vivo.
The effects of systemic or intratumoral F-araAMP in mice were investigated with human tumor xenografts (300 mg) in which 10% of the cells expressed E. coli PNP from a lentiviral promoter. Tumors injected with an adenoviral vector expressing E. coli PNP (Ad/PNP; 2 × 1011 viral particles, 2×/day × 3 days) and the impact of radiotherapy on tumors treated by this approach were also studied. Radiolabeled F-araAMP was used to monitor prodrug activation in vivo.
Intratumoral administration of F-araAMP in human tumor xenografts expressing E. coli PNP resulted in complete regressions and/or prolonged tumor inhibition. External beam radiation significantly augmented this effect. Injection of large human tumor xenografts (human glioma, non-small cell lung cancer, or malignant prostate tumors) with Ad/PNP followed by intratumoral F-araAMP resulted in excellent antitumor activity superior to that observed following systemic administration of prodrug.
Activation of F-araAMP by E. coli PNP results in destruction of large tumor xenografts in vivo, augments radiotherapy, and promotes robust bystander killing. Our results indicate that intratumoral injection of F-araAMP leads to ablation of tumors in vivo with minimal toxicity.
tumor sensitization; low growth fraction malignancy; fludarabine; viral gene transfer; E. coli PNP
Triple negative breast cancers (TNBC) frequently have high epidermal growth factor receptor (EGFR) expression and are sensitive to DNA-damaging agents. Improved therapies are needed for this aggressive malignancy.
Patients and methods
We performed a phase I trial of bendamustine and erlotinib, an EGFR tyrosine kinase inhibitor, in patients with metastatic TNBC, ECOG performance status ≤2, and ≤1 prior chemotherapy for metastatic disease. Each 28-day cycle included intravenous bendamustine on days 1, 2 and oral erlotinib on days 5–21 with dose escalation according to a 3 + 3 phase I study design. Dose-limiting toxicity (DLT) was determined by toxicities related to study therapy observed during cycle 1.
Eleven patients were treated, 5 on dose level 1 and 6 on dose level 2. One patient had DLT on dose level 2. However, cumulative toxicities were observed, including grade 3/4 lymphopenia in 91 % (95 % CI 0.59–0.998) with progressively decreased CD4 counts and grade ≥3 infections in 36 % (95 % CI 0.11–0.69) of patients.
Combination therapy with bendamustine and erlotinib causes excessive toxicity with severe, prolonged lymphopenia, depressed CD4 counts, and opportunistic infections and should not be pursued further. Future trials of bendamustine combinations in TNBC patients should account for potential cumulative lymphocyte toxicity necessitating patient monitoring during and after treatment.
Bendamustine; Erlotinib; Lymphopenia; Triple negative breast cancer; Metastatic breast cancer
The aim of the study is to dissect the cytotoxic mechanisms of 1-(4-hydroxy-3-methoxyphenyl)-7-(3,4-dihydroxyphenyl)-4E-en-3-heptanone (compound 1) in SH-SY5Y cells and therefore to provide new insight into neuroblastoma chemotherapy.
9 diarylheptanoids were isolated from Alpinia officinarum by chromatography and their cytotoxicity was evaluated by an MTS assay. Flow cytometry, Brdu incorporation assay and fluorescence staining were employed to investigate cytostatic and apoptotic effects induced by the compound 1. In addition, western blot, qPCR and siRNA techniques were used to elucidate the molecular mechanisms of the cytotoxicity.
The study to elucidate the cytotoxic mechanisms of compound 1, the most potent diarylheptanoid showed that cell cycle related proteins cyclins, CDKs and CDKIs as well as two main apoptotic related families caspase and Bcl 2 were involved in S phase arrest and apoptosis in neuroblastoma cell line SH-SY5Y. Furthermore, following the drug treatment, the protein expression of p53, phospho-p53 (Ser20) as well as the p53 transcriptional activated genes ATF3, puma and Apaf-1 were increased dramatically; MDM2 and Aurora A, the two p53 negative regulators were decreased; the p53 protein stability was enhanced whereas the p53 mRNA expression level slightly decreased and ATF3 mRNA expression apparently increased. In addition, the knockdown of ATF3 gene by siRNA partially suppressed p53, caspase 3, S phase arrest and apoptosis triggered by compound 1.
These results suggest that compound 1 induces S phase arrest and apoptosis via up regulation of ATF3 and stabilization of p53 in SH-SY5Y cell line. Therefore, compound 1 might be a promising lead structure for neuroblastoma therapy.
diarylheptanoid; cell cycle arrest; apoptosis; p53; ATF3
Docetaxel is a taxane anticancer drug used in a wide variety of solid tumors. Liposomes are versatile drug carriers that may increase drug solubility, serve as sustained release systems, provide protection from drug degradation and toxicities, and help overcome multidrug resistance. This phase I study was conducted to determine the maximum tolerated dose, dose-limiting toxicities (DLTs), pharmacokinetics (PK), and clinical response of liposomal-encapsulated docetaxel (LE-DT) in patients with advanced solid tumor malignancies.
LE-DT was administered using a standard 3 + 3 dose escalation schema with dose levels of 50, 65, 85, 110, and 132 mg/m2 IV on a 3-week cycle. Toxicities were assessed using the NCI-CTCAE version 3.0, and response was assessed using RECIST criteria (version 1.0). PK samples were drawn during cycle 1 and analyzed using a non-compartmental analysis.
Twenty-four patients were treated for 1–30 cycles (median = 4). No DLTs were experienced through dose levels of 50, 65, 85, and 110 mg/m2. Two out of two patients experienced grade 4 neutropenia at the 132 mg/m2 dose level. When an additional three patients were treated at the expanded 110 mg/m2 dose level, two experienced grade 4 neutropenia. The 85 mg/m2 dose level was reassessed with an expanded group of three additional patients, and only one of three patients experienced grade 4 neutropenia. The protocol was amended to allow G-CSF during cycle 1, and an additional three patients were treated at 110 mg/m2 with no DLTs experienced. No patient experienced significant neuropathy, even patients treated for 19, 20, and 30 cycles. PK followed a two-compartment elimination pattern; there was no correlation between PK and toxicity. Two patients with thyroid and neuroendocrine cancer had partial responses (PR, 8 %), and one patient with non-small-cell lung cancer had an unconfirmed PR. Eight patients (33 %) had stable disease lasting more than 3 months, for a clinical benefit rate of 41 %.
LE-DT was well tolerated with expected toxicities of neutropenia, anemia, and fatigue, but without neuropathy or edema. Clinical benefit (SD + PR) was observed in 41 % of the patients. The recommended phase II dose of LE-DT is 85 mg/m2 without G-CSF or 110 mg/m2 with G-CSF.
Phase I; Liposomes; Docetaxel; Clinical trial
Pre-clinical data suggest that combining imatinib with traditional cytotoxic chemotherapy may improve imatinib efficacy. We conducted a Phase I study of imatinib in combination with paclitaxel in patients with advanced or metastatic solid tumors.
Patients were accrued to the study in a standard 3 + 3 design. Patients were restaged every two cycles, and those with stable disease (SD), or better, continued study treatment without interruption. Maximally tolerated doses (MTDs) and pharmacokinetic profiles of combination imatinib and paclitaxel were assessed.
Fifty-eight patients were enrolled, including 40 in the Phase I dose escalation portion. Alternating dose escalation of imatinib and paclitaxel on a 28-day cycle resulted in MTDs of 800 mg imatinib daily, on days 1–4, 8–11, 15–18, and 22–25, and 100 mg/m2 paclitaxel weekly, on days 3, 10, and 17. Two expansion cohorts, comprising 10 breast cancer patients and 8 patients with soft-tissue sarcomas, were enrolled at the MTDs. The most common adverse events were flu-like symptoms (64 %) and nausea/vomiting (71 %). The most common Grade 3/4 toxicities were neutropenia (26 %), flu-like symptoms (12 %), and pain (12 %). There were no relevant differences in the pharmacokinetic profiles of either drug when given in combination compared with alone. Thirty-eight subjects were evaluable for response, 18 (47.4 %) of whom experienced clinical benefit. Five patients (13.2 %) had a partial response (PR) and 13 patients (34.2 %) had SD; the average time to progression in those with clinical benefit was 17 weeks (range: 7–28 weeks).
This combination of imatinib and paclitaxel was reasonably safe and tolerable, and demonstrated evidence of anti-tumor activity. Further exploration in disease-specific Phase II trials is warranted.
Imatinib; Paclitaxel; Phase I
Suramin, a polysulfonated naphthylurea, inhibits the actions of polypeptide growth factors including acidic and basic fibroblast growth factors (aFGF and bFGF), which confer broad spectrum chemotherapy resistance. We hypothesized that suramin at non-cytotoxic doses in combination with weekly paclitaxel would be well tolerated and demonstrate anti-tumor activity.
Women with metastatic breast cancer who had been previously treated with a taxane in the adjuvant or metastatic setting were eligible. The primary objective of the phase I was to determine the dose of intravenous (IV) weekly suramin that resulted in plasma concentrations between 10 and 50 umol/l over 8–48 h (or the target range) in combination with IV 80 mg/m2 of weekly paclitaxel. The primary objective of the phase II trial was to determine the anti-tumor activity of the dosing regimen defined in phase I. Therapy was continued until disease progression or development of unacceptable toxicity.
Thirty-one patients were enrolled (9: phase I; 22: phase II). In phase I, no dose-limiting toxicities were observed. Pharmacokinetics during the first cycle showed suramin concentrations within the target range for 21 of 24 weekly treatments (88 %). In phase II, the objective response rate (ORR) was 23 % (95 % CI 8–45 %), the median progression-free survival was 3.4 months (95 % CI 2.1–4.9 months), and the median overall survival was 11.2 months (95 % CI 6.6–16.0 months).
Non-cytotoxic doses of suramin in combination with weekly paclitaxel were well tolerated. The efficacy was below the pre-specified criteria required to justify further investigation.
Suramin; Paclitaxel; Metastatic; breast cancer; Phase I; Phase II
In clinical oncology, combination treatments are widely used and increasingly preferred over single drug administrations. A better characterization of the interaction between drug effects and the selection of synergistic combinations represent an open challenge in drug development process. To this aim, preclinical studies are routinely performed, even if they are only qualitatively analyzed due to the lack of generally applicable mathematical models.
This paper presents a new pharmacokinetic–pharmacodynamic model that, starting from the well-known single agent Simeoni TGI model, is able to describe tumor growth in xenograft mice after the co-administration of two anticancer agents. Due to the drug action, tumor cells are divided in two groups: damaged and not damaged ones. The damaging rate has two terms proportional to drug concentrations (as in the single drug administration model) and one interaction term proportional to their product. Six of the eight pharmacodynamic parameters assume the same value as in the corresponding single drug models. Only one parameter summarizes the interaction, and it can be used to compute two important indexes that are a clear way to score the synergistic/antagonistic interaction among drug effects.
The model was successfully applied to four new compounds co-administered with four drugs already available on the market for the treatment of three different tumor cell lines. It also provided reliable predictions of different combination regimens in which the same drugs were administered at different doses/schedules.
A good and quantitative measurement of the intensity and nature of interaction between drug effects, as well as the capability to correctly predict new combination arms, suggest the use of this generally applicable model for supporting the experiment optimal design and the prioritization of different therapies.
Electronic supplementary material
The online version of this article (doi:10.1007/s00280-013-2208-8) contains supplementary material, which is available to authorized users.
Pharmacokinetic–pharmacodynamic model; Tumor growth inhibition model; Drug combination therapy; Drug interaction; Xenograft mice
Intravenously (i.v.) administered nanomedicines have the potential for tumour targeting due to the enhanced permeability and retention (EPR) effect, but in vivo tumour models are rarely calibrated with respect to functional vascular permeability and/or mechanisms controlling intratumoural drug release. Here the effect of tumour type and tumour size on EPR-mediated tumour localisation and cathepsin B-mediated drug release was studied.
Evans Blue (10 mg/kg) and an N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer–doxorubicin (Dox) conjugate (FCE28068) (5 mg/kg Dox-equiv) were used as probes and tumour levels (and Dox release) measured at 1 h after i.v. administration in a panel of murine and human xenograft tumours.
Evans Blue and FCE28068 displayed similar tumour levels in the range of 2–18 % dose/g at 1 h for B16F10 and L1210. Approximately half of the tumour models evaluated exhibited tumour size-dependent accumulation of FCE28068; smaller tumours had the highest accumulation. Administration of free Dox (5 mg/kg) produced tumour levels of <2.5 % dose/g independent of tumour size. Whereas the degree of EPR-mediated targeting showed ~12-fold difference across the tumour models evaluated, Dox release from FCE28068 at 1 h displayed ~200-fold variation.
Marked heterogeneity was seen in terms of EPR effect and Dox release rate, underlining the need to carefully calibrate tumour models used to benchmark nanomedicines against known relevant standard agents and for optimal development of strategies for late pre-clinical and clinical development.
Electronic supplementary material
The online version of this article (doi:10.1007/s00280-013-2209-7) contains supplementary material, which is available to authorized users.
EPR effect; Cathepsin B; Evans Blue; HPMA copolymer–doxorubicin; Nanomedicines
Thalidomide, originally developed as a sedative, was subsequently identified to have antiangiogenic properties. Lenalidomide is an antiangiogenic and immunomodulatory agent that has been utilized in the treatment of patients with brain tumors. We studied the pharmacokinetics and cerebrospinal fluid (CSF) penetration of thalidomide and lenalidomide in a nonhuman primate model.
A dose of 50 mg of thalidomide or 20 mg of lenalidomide were administered once orally to each of three rhesus monkeys. Plasma and CSF samples were obtained at specified intervals and the thalidomide or lenalidomide concentrations were determined by high-performance liquid chromatography with tandem mass spectrometry. Pharmacokinetic parameters were estimated using noncompartmental methods. CSF penetration was calculated as area under the concentration-time curve (AUC) CSF/AUC plasma.
For thalidomide, the median apparent clearance (Cl/F) was 2.9 mL/min/kg, the median plasma AUC was 80 µM•hr, and the median terminal half-life (t½) was 13.3 hours. For lenalidomide, the median Cl/F was 8.7 mL/min/kg, the median AUC was 9 µM•hr, and the median t½ was 5.6 hours. Thalidomide was detected in the CSF of all animals, with a median penetration of 42%. Lenalidomide was detected in the CSF of 2 of 3 animals, with a CSF penetration of 11% in each.
Thalidomide and lenalidomide penetrate into the CSF after oral administration of clinically relevant doses. Plasma exposure to lenalidomide was similar in our model to that observed in studies involving children who have brain tumors. These results support further development of lenalidomide for the treatment of central nervous system malignancies.
thalidomide; lenalidomide; pharmacokinetics; CSF penetration; nonhuman primates
Pasireotide (SOM230), a novel multireceptor ligand somatostatin analog (SSA), binds with high affinity to four of the five somatostatin receptor subtypes (sst1–3, 5). This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics profiles of pasireotide long-acting release (LAR) formulation in patients with advanced gastroenteropancreatic neuroendocrine tumor (GEP NET) refractory to other SSAs.
In this randomized, multicenter, open-label, phase II study, patients with biopsy-proven primary or metastatic GEP NET refractory to available SSAs were randomly assigned 1:1:1 to receive pasireotide LAR by deep intragluteal injection at a dose of 20, 40, or 60 mg once every 28 days for 3 months.
Forty-two patients received pasireotide LAR. Adverse events were reported by 34 (81 %) patients, with the most frequently reported including diarrhea, fatigue, abdominal pain, and nausea. Mean fasting glucose levels were increased compared with baseline at all points throughout the study. After the third injection of pasireotide LAR, the median trough plasma concentrations on day 84 were 4.82, 12.0, and 19.7 ng/mL in the 20-, 40-, and 60-mg treatment groups, respectively. Drug accumulation was limited for each dose based on the increase in trough concentrations after the first to third injections (accumulation ratios were approximately 1 from all dose levels).
This study demonstrated that a new, once-monthly, intramuscular LAR formulation of pasireotide was well tolerated in patients with advanced GEP NET. Steady state levels of plasma pasireotide were achieved after three injections.
Pasireotide (SOM230); Gastroenteropancreatic neuroendocrine tumor (GEP NET); Safety; Pharmacokinetics; Pharmacodynamics
It is advantageous to individualize high-dose methotrexate (HDMTX) to maintain adequate exposure while minimizing toxicities. Previously, we accomplished this through within-course dose adjustments.
In this study, we evaluated a strategy to individualize HDMTX based on clearance of each individual’s previous course of HDMTX in 485 patients with newly diagnosed acute lymphoblastic leukemia. Doses were individualized to achieve a steady-state plasma concentration (Cpss) of 33 or 65 μM (approximately 2.5 or 5 g/m2/day) for low- and standard-/high-risk patients, respectively.
Individualized doses resulted in 70 and 63 % of courses being within 20 % of the targeted Cpss in the low- and standard-/high-risk arms, respectively, compared to 60 % (p < 0.001) and 61 % (p = 0.43) with conventionally dosed therapy. Only 1.3 % of the individualized courses in the standard-/high-risk arm had a Cpss greater than 50 % above the target compared to 7.3 % (p < 0.001) in conventionally dosed therapy. We observed a low rate (8.5 % of courses) of grade 3–4 toxicities. The odds of gastrointestinal toxicity were related to methotrexate plasma concentrations in both the low (p = 0.021)- and standard-/high-risk groups (p = 0.003).
Individualizing HDMTX based on the clearance from the prior course resulted in fewer extreme Cpss values and less delayed excretion compared to conventional dosing.
Electronic supplementary material
The online version of this article (doi:10.1007/s00280-013-2206-x) contains supplementary material, which is available to authorized users.
Methotrexate; Acute lymphoblastic leukemia; Pharmacokinetics; Individualized therapy
The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor gefitinib (ZD1839, Iressa) is approved for cancer treatment. We investigated whether gefitinib treatment can enhance human EGF (hEGF) uptake in vitro, thereby increasing the potential of hEGF as a vehicle for EGFR-targeted therapy.
Western blotting was used to detect the effect of gefitinib on EGFR signaling. Different EGFR-expressing tumor cells (SCC-1, 22B, A549, and HT-29) were pretreated with gefitinib, and then with 125I-hEGF or 125I-Vectibix (an anti-EGFR monoclonal antibody). Cell-associated activity was then measured. A cross-linking assay detected increased EGFR dimer formation in gefitinib-treated cells.
Total EGFR levels were not changed, but EGFR phosphorylation was reduced in cells pretreated with gefitinib. Gefitinib mediated formation of EGFR dimers; binding of 125I-hEGF to cells pretreated with gefitinib significantly increased. In contrast, binding of 125I-Vectibix to tumor cells did not increase. Although total EGFR levels did not increase, binding of hEGF to EGFR + tumors was significantly enhanced after gefitinib treatment, because of increased hEGF binding to gefitinib-induced EGFR dimers.
These results suggest that hEGF could enhance EGFR-targeting when used with gefitinib.
Gefitinib; hEGF; EGFR; Dimer
Sphingosine kinase is an oncogene that is up-regulated in several solid tumors. The product of the sphingosine kinase activity, sphingosine-1-phosphate is a potent mitogen involved in diverse cell processes such as cell survival and migration. Current standard therapy in the treatment of glioblastoma multiforme (GBM) is a combination of surgery, radiation, and chemotherapy using the drug temozolomide (TMZ). However, virtually all tumors become resistant to TMZ. Therefore, new drug targets are necessary. In this study, we investigated whether inhibiting sphingosine kinase could induce cell death in TMZ-resistant GBM cells.
To study TMZ resistance in vitro, we have generated TMZ-resistant cell lines from established GBM cells. We used a potent inhibitor of sphingosine kinase to study its effect on colony formation and cell growth in GBM cells with a limited dilution and WST assay. Moreover, cell death was determined by measuring caspase-3 activity using flow cytometry.
A sphingosine kinase inhibitor reduced cell colony formation and activated caspase-3 in both TMZ-sensitive and resistant GBM cells.
Addition of a sphingosine kinase inhibitor to the standard chemotherapy regimen against GBM may be beneficial.
Glioblastoma; Sphingosine; Sphingosine kinase; Inhibitor
Imatinib is an inhibitor of the Bcr-Abl tyrosine kinase; however, resistance is common. Flavopiridol, a cyclin-dependent kinase (CDK) inhibitor, down-regulates short-lived anti-apoptotic proteins via inhibition of transcription. In preclinical studies, flavopiridol synergizes with imatinib to induce apoptosis. We investigated this novel combination regimen in patients with Bcr-Abl+ malignancies.
In a phase I dose-escalation study, imatinib was administered orally daily, and flavopiridol by 1-hour intravenous infusion weekly for three weeks every four weeks. Adults with chronic myelogenous leukemia (CML) or Philadelphia chromosome-positive (Ph+) acute leukemias were eligible. Patients were divided into two strata based on peripheral blood and bone marrow blast counts. The primary objective was to identify the recommended phase II doses (RPTD) for the combination. Correlative pharmacokinetic and pharmacodynamic studies were also performed.
A total of 21 patients received study treatment. Four dose levels were evaluated before the study was closed following the approval of the second generation Bcr-Abl tyrosine kinase inhibitors (TKIs). Five patients responded, including four sustained responses. Four patients had stable disease. All but one responder, and all patients with stable disease had previously been treated with imatinib. One patient had a complete response sustained for 30 months. Changes in expression of phospho-Bcr/Abl, -Stat5, and Mcl-1 were monitored. No major pharmacokinetic interaction was observed.
This is the first study to evaluate the combination of a CDK inhibitor and a TKI in humans. The combination of flavopiridol and imatinib is tolerable and produces encouraging responses, including in some patients with imatinib-resistant disease.
Imatinib; flavopiridol; cyclin dependent kinase inhibitor; CDK inhibitor; Bcr-Abl; tyrosine kinase inhibitor