Phase 1 trials play a crucial role in oncology by translating laboratory science into efficient therapies. Molecular targeted agents (MTA) differ from traditional cytotoxics in terms of both efficacy and toxicity profiles. Recent reports suggest that higher doses are not essential to produce the optimal anti-tumor effect. This study aimed to assess if MTA could achieve clinical benefit at much lower dose than traditional cytotoxics in dose seeking phase 1 trials.
Patients and Methods
We reviewed 317 recent phase 1 oncology trials reported in the literature between January 1997 and January 2009. First sign of efficacy, maximum tolerated dose (MTD) and their associated dose level were recorded in each trial.
Trials investigating conventional cytotoxics alone, MTA alone and combination of both represented respectively 63.0% (201/317), 23.3% (74/317) and 13.7% (42/317) of all trials. The MTD was reached in 65.9% (209/317) of all trials and was mostly observed at the fifth dose level. First sign of efficacy was less frequently observed at the first three dose-levels for MTA as compared to conventional cytotoxics or combinations regimens (48.3% versus 63.2% and 61.3%). Sign of efficacy was observed in the same proportion whatever the treatment type (73–82%). MTD was less frequently established in trials investigating MTA alone (51.3%) or combinations (42.8%) as compared to conventional cytotoxic agents (75.6%).
First sign of efficacy was less frequently reported at the early dose-levels and MTD was less frequently reached in trials investigating molecular targeted therapy alone. Similar proportion of trials reported clinical benefit.
Phase-I trials traditionally involve dose-escalation to determine the maximal tolerated dose (MTD). With conventional chemotherapy, efficacy is generally deemed to be dose-dependent, but the same may not be applicable to molecularly targeted agents (MTAs). We analysed consecutive patients included in Phase-I trials at the Royal Marsden Hospital from 5 January 2005 to 6 June 2006. We considered only trials of monotherapy MTAs in which the MTD was defined. Three patient cohorts (A, B, and C) were identified according to the dose received as a percentage of the final trial MTD (0–33%, 34–65%, >66%). Potential efficacy was assessed using the non-progression rate (NPR), that is, complete/partial response or stable disease for at least 3 months by RECIST. A total of 135 patients having progressive disease before enrolment were analysed from 15 eligible trials. Median age was 57 years (20–86); male : female ratio was 1.8 : 1. Cohort A, B, and C included 28 (21%), 22 (16%), and 85 (63%) patients; NPR at 3 and 6 months was 21% and 11% (A), 50% and 27% (B), 31% and 14% (C), respectively, P=0.9. Median duration of non-progression (17 weeks; 95% CI=13–22) was not correlated with the MTD level, P=0.9. Our analysis suggests that the potential for clinical benefit is not confined to patients treated at doses close to the MTD in Phase-I trials of MTAs.
Phase-I trial; molecularly targeted agents; maximal tolerated dose; non-progression rate; clinical benefit
The extent to which a drug inhibits a target responsible for a therapeutic effect is a more rational primary endpoint for dose-finding studies of more selective anticancer drugs than the conventional endpoint of dose-limiting toxicity (DLT) used for cytotoxic agents. An adaptive phase I trial design incorporating maximum target inhibition as the primary endpoint was developed to define the optimal dose of talabostat, a dipeptidyl peptidase (DPP) inhibitor, in children with relapsed or refractory solid tumors. The relationship between dose and effect (percent inhibition of serum DPP-4) was assessed using a maximum effect model. Maximum target inhibition was defined as greater than 90% DPP-4 inhibition in five or more of six patients 24 hours post-dose. If DLT was to occur, the trial would adapt to a traditional phase I design with a more conservative dose escalation. At the 600 μg/m2 dose level, serum DPP-4 inhibition at 24 hours was 85%. No talabostat-related DLT occurred. The maximum effect model predicted that 1200 μg/m2 of talabostat would maximally inhibit DPP-4. This adaptive trial design appears to be feasible, safe, and efficient and warrants further evaluation for development of molecularly targeted agents.
ABT-751 is a novel antimitotic agent that confers cytotoxic effects in pre-clinical studies. Carboplatin has efficacy in treating advanced non-small cell lung cancer (NSCLC) in combination with other drugs.
Lung cancer cell lines were treated with ABT-751 and/or carboplatin to investigate their impact on cell growth. Phase I study with an expansion cohort was conducted in previously treated NSCLC patients. The primary objective was the maximum tolerated dose (MTD), secondary objectives were objective response rates, median survival, time to tumor progression (TTP), dose-limiting toxicities (DLTs), and pharmacodynamic evaluation of buccal swabs.
Combining ABT-751 with carboplatin significantly reduced growth and induced apoptosis in lung cancer cell lines. Twenty advanced NSCLC patients were enrolled. MTD was ABT-751 125 mg orally twice daily for 7 days with carboplatin AUC 6. DLTs included fatigue, ileus, neutropenia and pneumonitis. Two patients had confirmed partial responses. Median overall survival was 11.7 months (95% CI 5.9–27.0). TTP was 2.8 months (95% CI 2.0–2.7). Four of 6 patients showed decreased cyclin D1 protein in post-treatment versus pre-treatment buccal swabs.
Combining ABT-751 with carboplatin suppressed growth of lung cancer cell lines and had modest clinical anti-tumor activity in advanced NSCLC previously treated predominantly with carboplatin. Further studies of this combination are not recommended while investigations of biomarkers in different patient populations, alternative schedules and combinations may be pursued.
ABT-751; carboplatin; phase I clinical trial; non-small cell lung cancer
To safely assess new drugs, cancer patients in initial cohorts of phase I oncology studies receive low drug doses. Doses are successively increased until the maximum tolerated dose (MTD) is determined. Since traditional chemotherapy is often more effective near the MTD, ethical concerns have been raised regarding administration of low drug doses to phase I patients. However, a substantial portion of oncology trials now investigate targeted agents, which may have different dose-response relationships than cytotoxic chemotherapies.
Twenty-four consecutive trials treating 683 patients between 10-01-2004 and 6-30-2008 at MD Anderson Cancer Center were analyzed. Patients were assigned to a low-dose (≤25% MTD), medium-dose (25–75% MTD), or high-dose (≥75% MTD) group, and groups were compared for response rate, time-to-treatment-failure, progression-free survival, overall survival, and toxicity. To remove negatively biasing data from the high-dose group, in a second analysis patients treated above the MTD were excluded (high-dose group = 75–100% MTD). 97.7% of patients received targeted agents.
Even when excluding patients above the MTD, there was an early trend favoring the low- versus high-dose group in time-to-treatment-failure, with 32.9% versus 25.2% of patients on therapy at 3 months (p=0.08). Additionally, the low-dose group fared at least as well as the other groups in all other outcomes, including response rate, progression-free survival, overall survival, and toxicity.
These data may help alleviate concerns that patients who receive low drug doses on contemporary phase I oncology trials fare worse, and suggest targeted agents may have different dose-response relationships than cytotoxic chemotherapies.
Phase I clinical trials are an essential step in the development of anticancer drugs. The main goal of these studies is to establish the recommended dose and/or schedule of new drugs or drug combinations for phase II trials. The guiding principle for dose escalation in phase I trials is to avoid exposing too many patients to subtherapeutic doses while preserving safety and maintaining rapid accrual. Here we review dose escalation methods for phase I trials, including the rule-based and model-based dose escalation methods that have been developed to evaluate new anticancer agents. Toxicity has traditionally been the primary endpoint for phase I trials involving cytotoxic agents. However, with the emergence of molecularly targeted anticancer agents, potential alternative endpoints to delineate optimal biological activity, such as plasma drug concentration and target inhibition in tumor or surrogate tissues, have been proposed along with new trial designs. We also describe specific methods for drug combinations as well as methods that use a time-to-event endpoint or both toxicity and efficacy as endpoints. Finally, we present the advantages and drawbacks of the various dose escalation methods and discuss specific applications of the methods in developmental oncotherapeutics.
Some of the problems in extrapolating laboratory animal toxicity data to man are considered. The quantitative predictiveness of preclinical studies of anticancer drugs using dogs and monkeys for man has also been examined. The relationship between the maximum tolerated dose (MTD) in the dog, monkey, and the more sensitive of the two species and clinical observations are discussed. The effectiveness of using doses expressed on the basis of body weight (mg/kg) and body surface area (mg/m2) are compared. A method is introduced to assess the "statistical risk" associated with the extrapolation of the initial clinical (phase I) dose from experimental animal data. The best clinical prediction is obtained when one uses the experimental MTD expressed in mg/kg for the more sensitive of the large animal species (dogs or monkeys). The clinical introduction of a new anticancer agent at a dose 1/10 the MTD in the more sensitive species carries a statistical risk of about 3%; that is, the initial doses of about 3 of every 100 new drugs introduced into the clinic will produce some toxic effects in man. These same data have been extended theoretically to the total population and toxic chemicals in general. Reliable extrapolation from laboratory test models to man requires a much more complete understanding of structure--activity relationships, pharmacokinetic factors, and mechanisms of toxicity.
Patients recruited in phase I oncology trials are often treated at doses lower than the maximum tolerated dose (MTD), and therefore may not receive the most efficacious dose available, despite their expectations to the contrary. This report investigates the consequences of allowing a patient choice of dose within a common dose-escalation scheme.
Trials using the continual reassessment method of dose escalation are simulated, with a modification of the rules to allow patients to choose a higher dose if they wish. The effect of allowing this choice is assessed in terms of probability of toxicity and probability of being treated at the MTD or higher.
The simulations show that allowing a patient choice of dose reduces the proportions of patients treated at doses lower than the MTD, and has little impact on the overall probability of correct identification of the MTD.
The results illustrate the principle that a choice of dose can be offered to patients in such trials without compromising the overall properties of the study.
phase I; oncology; continual reassessment method; ethics; dose escalation
Metronomic chemotherapy involves frequent, regular administration of cytotoxic drugs at nontoxic doses, usually without prolonged breaks. We investigated the therapeutic efficacies of metronomic S-1, an oral 5-fluorouracil prodrug, and vandetanib, an epidermal growth factor receptor and vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor, in models of hepatocellular carcinoma (HCC).
We compared anti-HCC effects and toxicity in the six treatment groups: control (untreated), maximum tolerated dose (MTD) S-1, metronomic S-1, vandetanib, MTD S-1 with vandetanib, and metronomic S-1 with vandetanib. Tumor microvessel density (MVD) and tumor apoptosis were evaluated by immunohistochemistry. The expression of VEGF and thrombospondin-1, an endogenous inhibitor of angiogenesis, was analyzed by Western blot.
Metronomic S-1 significantly inhibited tumor growth, which was enhanced by combination with vandetanib. With respect to toxicities, MTD S-1 caused severe body weight loss and myelosuppression, whereas metronomic S-1 did not cause any overt toxicities. Moreover, metronomic S-1 or metronomic S-1 with vandetanib prolonged survival, the latter treatment providing the greatest benefit. Metronomic S-1 and metronomic S-1 with vandetanib decreased MVDs and increased apoptosis in tumor tissues. The expression of VEGF in tumor tissues was upregulated by vandetanib and metronomic S-1 with vandetanib, whereas the expression of thrombospondin-1 was upregulated by metronomic S-1 and metronomic S-1 with vandetanib.
Metronomic S-1 with an antiangiogenic agent seems to be an effective and safe therapeutic strategy for HCC.
Preclinical toxicology studies are performed prior to phase I trials with novel cancer therapeutics to identify a safe clinical starting dose and potential human toxicities. The primary aim of this study was to evaluate the ability of rodent-only toxicology studies to identify a safe phase I trial starting dose. In addition, the ability of murine studies to predict the quantitative and qualitative human toxicology of cancer therapeutics was studied. Data for 25 cancer drugs were collated for which the preclinical and clinical routes and schedules of administration were either the same (22/25), or closely matched. The maximum tolerated dose/dose lethal to 10% of mice (MTD/LD10) was identified for 24 drugs, and in patients the maximum administered dose (MAD) was associated with dose-limiting toxicity (DLT) in initial clinical trials with 20 compounds. In addition, for 13 agents, the toxicity of the drug at one-tenth the mouse MTD/LD10 was also investigated in rats, following repeated administration (20 doses). A phase I trial starting dose of one-tenth the mouse MTD/LD10 (mg m–2) was, or would have been, safe for all 25 compounds. With the exception of nausea and vomiting, which cannot be assessed in rodents, other common DLTs were accurately predicted by the murine studies (i.e. 7/7 haematological and 3/3 neurological DLTs). For two of the 13 drugs studied in rats, repeated administration of one-tenth the mouse MTD/LD10 was toxic, leading to a reduction in the phase I trial starting dose; however, one-tenth the mouse MTD/LD10 was subsequently tolerated in patients. For the 20 drugs where clinical DLT was reached, the median ratio of the human MAD to the mouse MTD/LD10 was 2.6 (range 0.2–16) and the median ratio of the clinical starting dose to the MAD was 35 (range 2.3–160). In contrast, in 13 subsequent phase I trials with 11 of the initial 25 drugs, the median ratio of the clinical starting dose to the MAD was 2.8 (range 1.6–56), emphasizing the value of early clinical data in rapidly defining the dose range for therapeutic studies. For all 25 drugs studied, rodent-only toxicology provided a safe and rapid means of identifying the phase I trial starting dose and predicting commonly encountered DLTs. This study has shown that the routine use of a non-rodent species in preclinical toxicology studies prior to initial clinical trials with cancer therapeutics is not necessary. © 1999 Cancer Research Campaign
phase I trials; preclinical toxicology; starting dose
Pemetrexed (MTA) is a multitargeted antifolate drug approved for lung cancer therapy. Clinically, supplementation with high doses of folic acid (FA) and vitamin B12 (VB12) lowers MTA cytotoxicities. An antagonistic effect of FA/VB12 on MTA efficacy has been proposed. However, patients who receive FA/VB12 show better tolerance to MTA with improved survival. The aims of this study are to investigate the modulation of FA and VB12 on MTA drug efficacy in human nonsmall cell lung cancer (NSCLC) cell lines. The sensitivities of cells, apoptosis, and MTA-regulated proteins were characterized to determine the possible effects of high doses of FA and VB12 on MTA efficacy. MTA has the lowest efficacy under 10% serum conditions. However, supplementation with FA and VB12 individually and additively reversed the insensitivity of NSCLC cells to MTA treatment with 10% serum. The enhanced sensitivities of cells following FA/VB12 treatment were correlated with increasing apoptosis and were specific to MTA but not to 5-fluorouracil (5-FU). Enhanced sensitivity was also associated with p21WAF1/Cip1 expression level. Our results revealed no antagonistic effect of high doses of FA/VB12 on MTA efficacy in cancer cells grown in nutrient medium. Furthermore, these data may partially explain why supplementation of FA and VB12 resulted in better survival in MTA-treated patients.
A Phase I study to define toxicity and recommend a Phase II dose of the HSP90 inhibitor alvespimycin (17-DMAG; 17-dimethylaminoethylamino-17-demethoxygeldanamycin). Secondary endpoints included evaluation of pharmacokinetic profile, tumor response and definition of a biologically effective dose (BED).
Patients and Methods
Patients with advanced solid cancers were treated with weekly, intravenous (IV) 17-DMAG. An accelerated titration dose escalation design was used. The maximum tolerated dose (MTD) was the highest dose at which ≤ 1/6 patients experienced dose limiting toxicity (DLT). Dose de-escalation from the MTD was planned with mandatory, sequential tumor biopsies to determine a BED. Pharmacokinetic and pharmacodynamic assays were validated prior to patient accrual.
Twenty five patients received 17-DMAG (range 2.5 to 106 mg/m2). At 106mg/m2 of 17-DMAG 2/4 patients experienced DLT, including one treatment related death. No DLT occurred at 80mg/m2. Common adverse events were gastrointestinal, liver function changes and ocular. AUC and Cmax increased proportionally with 17-DMAG doses ≤ 80mg/m2. In peripheral blood mononuclear cells significant (p <0.05) HSP72 induction was detected (≥ 20mg/m2) and sustained for 96 hours (≥ 40mg/m2). Plasma HSP72 levels were greatest in the two patients who experienced DLT. At 80mg/m2 client protein (CDK4, LCK) depletion was detected and tumor samples from 3/5 patients confirmed HSP90 inhibition. Clinical activity included complete response (castration refractory prostate cancer, CRPC 124 weeks), partial response (melanoma, 159 weeks) and stable disease (chondrosarcoma, CRPC and renal cancer for 28, 59 and 76 weeks respectively).
The recommended Phase II dose of 17-DMAG is 80mg/m2 weekly, IV.
Statement of translational relevance
Despite significant efforts over the last two decades aimed at improving the efficacy of standard treatment (maximum tolerated dose (MTD) of dacarbazine), there has been no significant increase in the median survival of patients suffering from metastatic melanoma. Given the lack of success achieved, a rethinking of alternative treatment strategies is needed. Using preclinical models of advanced melanoma metastasis, we show that metronomic chemotherapeutic combinations results in improved survival, which is achieved with minimal toxicity. These results compare favorably with minimal effectiveness achieved by MTD dacarbazine therapy (alone or in combination with other chemotherapeutic agents or a VEGFR-blocking antibody), often accompanied by higher toxicity. Successes in preclinical setting of metastatic breast cancer have led to a clinical trial to examine the efficacy of metronomic therapy. A similar extension of the metronomic chemotherapeutic combinations presented here into the clinical setting of melanoma metastasis may be warranted.
The development of effective therapeutic approaches for treatment of metastatic melanoma remains an immense challenge. Present therapies offer minimal benefit. While dacarbazine (DTIC) chemotherapy remains the standard therapy, it mediates only low response rates, usually of short duration, even when combined with other chemotherapeutic agents. Thus, new therapeutic strategies are urgently needed.
Using a newly developed preclinical model, we evaluated the efficacy of various doublet metronomic combination chemotherapy against established, advanced melanoma metastasis and compared these to the standard maximum tolerated dose (MTD) DTIC (alone or in combination with chemotherapeutic agents or VEGFR-blocking antibody)
Whereas MTD DTIC therapy did not cause significant improvement in median survival, a doublet combination of low-dose metronomic (LDM) vinblastine (Vbl) and LDM cyclophosphamide (CTX) induced a significant increase in survival with only minimal toxicity. Furthermore, we show that the incorporation of the LDM Vbl/LDM CTX combination with a LDM DTIC regimen also results in a significant increase in survival, but not when combined with MTD DTIC therapy. We also show that a combination of metronomic Vbl therapy and a VEGFR2-blocking antibody (DC101) results in significant control of metastatic disease and that the combination of LDM Vbl/DC101 and LDM DTIC induced a significant improvement in median survival.
The effective control of advanced metastatic melanoma achieved by these metronomic-based chemotherapeutic approaches warrants clinical consideration of this treatment concept given the recent results of a number of metronomic-based chemotherapy clinical trials.
melanoma; spontaneous metastasis; vinblastine; cyclophosphamide; DC101; metronomic chemotherapy
The current standard of care for pancreatic cancer is weekly gemcitabine administered for 3 of 4 weeks with a 1-week break between treatment cycles. Maximum tolerated dose (MTD)-driven regimens as such are often associated with toxicities. Recent studies demonstrated that frequent dosing of chemotherapeutic drugs at relatively lower doses in metronomic regimens also confers anti-tumour activity but with fewer side effects.
Herein, we evaluated the anti-tumour efficacy of metronomic vs MTD gemcitabine, and investigated their effects on the tumour microenvironment in two human pancreatic cancer xenografts established from two different patients.
Metronomic and MTD gemcitabine significantly reduced tumour volume in both xenografts. However, Ktrans values were higher in metronomic gemcitabine-treated tumours than in their MTD-treated counterparts, suggesting better tissue perfusion in the former. These data were further supported by tumour-mapping studies showing prominent decreases in hypoxia after metronomic gemcitabine treatment. Metronomic gemcitabine also significantly increased apoptosis in cancer-associated fibroblasts and induced greater reductions in the tumour levels of multiple pro-angiogenic factors, including EGF, IL-1α, IL-8, ICAM-1, and VCAM-1.
Metronomic dosing of gemcitabine is active in pancreatic cancer and is accompanied by pronounced changes in the tumour microenvironment.
tumour microenvironment; pancreatic cancer; metronomic chemotherapy; gemcitabine; anti-angiogenesis
Cytoreductive surgery with intraperitoneal hyperthermic chemoperfusion (IPHC) has evolved into a promising approach for peritoneal surface malignancy. A large body of literature suggests that oxaliplatin has excellent cytotoxicity against colorectal cancer. Therefore, we undertook a phase I evaluation of IPHC with oxaliplatin for peritoneal dissemination from colorectal and appendiceal cancers to establish the dose-limiting toxicity (DLT) and the maximum tolerated dose (MTD).
Cohorts of three patients underwent cytoreductive surgery followed by a 2-h IPHC with escalating doses of oxaliplatin at a target outflow temperature of 40°C. The initial peritoneal oxaliplatin dose was 200 mg/M2 with increases planned in 50 mg/M2 increments. Plasma and perfusate samples were collected during the IPHC and evaluated using emission spectrometry techniques. Normal tissue and tumor samples were collected before and after the IPHC for analysis. DLT was defined as a grade 3 toxicity lasting 5 days.
Fifteen patients were enrolled at two dose levels. Peritoneal fluid areas under the curve (AUCs) were above those of plasma. Additionally, intratumoral oxaliplatin was similar to that of surrounding normal tissue. Dose-limiting toxicities at 250 mg/M2 were observed in two of three patients enrolled in this study.
We found that IPHC with 200 mg/M2 of oxaliplatin is well tolerated and is the MTD for a 2-h chemoperfusion. Higher doses are not feasible with this perfusion protocol given the significant toxicities associated with 250 mg/M2 oxaliplatin. Based on the data from this phase I study, we propose to conduct further studies with oxaliplatin delivered at 200 mg/M2.
Oxaliplatin; Surgery; Intraperitoneal hyperthermic chemoperfusion; Carcinomatosis; Phase I trial
Medicinal inorganic chemistry has been stimulating largely by the success of the anticancer drug, cisplatin. Various metal complexes are currently used as therapeutic agents (e.g., Pt, Au, and Ru) in the treatment of malignant diseases, including several types of cancers. Understanding the mechanism of action of these metal-based drugs is for the design of more effective drugs. Proteomic approaches combined with other biochemical methods can provide comprehensive understanding of responses that are involved in metal-based anticancer drugs-induced cell death, including insights into cytotoxic effects of metal-based anticancer drugs, correlation of protein alterations to drug targets, and prediction of drug resistance and toxicity. This information, when coupled with clinical data, can provide rational basses for the future design and modification of present used metal-based anticancer drugs.
Temozolomide, an oral cytotoxic agent with approximately 100% bioavailability after one administration, has demonstrated schedule-dependent clinical activity against highly resistant cancers. Thirty patients with minimal prior chemotherapy were enrolled in this phase I trial to characterize the drug's safety, pharmacokinetics and anti-tumour activity, as well as to assess how food affects oral bioavailability. To determine dose-limiting toxicities (DLT) and the maximum tolerated dose (MTD), temozolomide 100–250 mg m−2 was administered once daily for 5 days every 28 days. The DLT was thrombocytopenia, and the MTD was 200 mg m−2 day−1. Subsequently, patients received the MTD to study how food affects the oral bioavailability of temozolomide. When given orally once daily for 5 days, temozolomide was well tolerated and produced a non-cumulative, transient myelosuppression. The most common non-haematological toxicities were mild to moderate nausea and vomiting. Clinical activity was observed against several advanced cancers, including malignant glioma and metastatic melanoma. Temozolomide demonstrated linear and reproducible pharmacokinetics and was rapidly absorbed (mean Tmax ~1 h) and eliminated (mean t1/2 = 1.8 h). Food produced a slight reduction (9%) in absorption of temozolomide. Temozolomide 200 mg m−2 day−1 for 5 days, every 28 days, is recommended for phase II studies. © 1999 Cancer Research Campaign
oral; cytotoxic; chemotherapy; pharmacokinetics; dose escalation
To determine the maximum tolerated dose (MTD), characterize the principal toxicities, and assess the pharmacokinetics of EKB-569, an oral selective irreversible inhibitor of the epidermal growth factor receptor tyrosine kinase, in combination with capecitabine in patients with advanced colorectal cancer.
Patients were treated with EKB-569 daily for 21days and capecitabine twice daily for14 days of a 21-day cycle. The dose levels of EKB-569 (mg/day) and capecitabine (mg/m2 twice daily) assessed were 25/750, 50/750, 50/1,000 and 75/1,000. An expanded cohort was enrolled at the MTD to better study toxicity and efficacy. Samples of plasma were collected to characterize the pharmacokinetics of the agents. Treatment efficacy was assessed every other cycle.
A total of 37 patients, the majority of whom had prior chemotherapy, received a total of 163 cycles of treatment. Twenty patients were treated at the MTD, 50 mg EKB-569, daily and 1,000 mg/m2 capecitabine twice daily. Dose-limiting toxicities were diarrhea and rash. No patients had complete or partial responses but 48% had stable disease. The conversion of capecitabine to 5-fluorouracil was higher for the combination of EKB-569 and capecitabine (321 ± 151 ng*h/mL) than for capecitabine alone (176 ± 62 ng*hours/mL; P = 0.0037).
In advanced colorectal cancer, 50 mg EKB-569 daily can be safely combined with 1,000 mg/m2 capecitabine twice a day. A statistically significant increase in plasma levels of 5-fluorouracil for the combination of EKB-569 and capecitabine may be due to the single-dose versus multiple-dose exposure difference, variability in exposure or a potential drug interaction.
This review focuses on the current understanding of the pathophysiology and mechanisms of macrovascular toxicities (hypertension, hemorrhage, and thromboembolism) of molecularly targeted anticancer therapies, their incidence and severity, the current clinical management, and implications in the advanced cancer setting.
The introduction of molecularly targeted anticancer therapies has brought the promise of longer survival times for select patients with cancers previously considered untreatable. However, it has also brought new toxicities that require understanding and management, sometimes for long periods of time. Vascular endothelial growth factor inhibitors are associated with a broad range of adverse effects, with vascular toxicity being particularly serious. This review focuses on the current understanding of the pathophysiology and mechanisms of macrovascular toxicities (hypertension, hemorrhage, and thromboembolism), their incidence and severity, the current clinical management, and implications in the advanced cancer setting. Movement of these agents into the early disease setting will alter the impact of these toxicities.
Search Strategy and Selection Criteria.
Information for this review was collected by searching PubMed/Medline and American Society of Clinical Oncology abstract databases. The medical subject heading terms used included toxicity, hypertension, thromboembolism, hemorrhage, intestinal perforation, risk factors, pharmacokinetics, and metabolism, combined with free text search terms including, but not limited to, VEGF inhibitor*, bevacizumab, sunitinib, and sorafenib. Articles published in English before March 2010 were included, in addition to information from case reports and pharmaceutical agent package inserts.
VEGF inhibition; Treatment toxicity; Hypertension; Hemorrhage; Thromboembolism
Background Targeting the cell-surface receptor EphA2, which is highly expressed in some solid tumors, is a novel approach for cancer therapy. We aimed to evaluate the safety profile, maximum tolerated dose (MTD), pharmacokinetics, and antitumor activity of MEDI-547, an antibody drug conjugate composed of the cytotoxic drug auristatin (toxin) linked to a human anti-EphA2 monoclonal antibody (1C1), in patients with solid tumors relapsed/refractory to standard therapy. Methods In this phase 1, open-label study with planned dose-escalation and dose-expansion cohorts, patients received a 1-h intravenous infusion of MEDI-547 (0.08 mg/kg) every 3 weeks. Results Six patients received 0.08 mg/kg; all discontinued treatment. Dose escalation was not pursued. The study was stopped before cohort 2 enrollment due to treatment-related bleeding and coagulation events (hemorrhage-related, n = 3; epistaxis, n = 2). Therefore, lower doses were not explored and an MTD could not be selected. The most frequently reported treatment-related adverse events (AEs) were increased liver enzymes, decreased hemoglobin, decreased appetite, and epistaxis. Three patients (50%) experienced treatment-related serious AEs, including conjunctival hemorrhage, pain (led to study drug discontinuation), liver disorder, and hemorrhage. Best response included progressive disease (n = 5; 83.3%) and stable disease (n = 1; 16.7%). Minimal or no dissociation of toxin from 1C1 conjugate occurred in the blood. Serum MEDI-547 concentrations decreased rapidly, ~70% by 3 days post-dose. No accumulation of MEDI-547 was observed at 0.08 mg/kg upon administration of a second dose 3 weeks following dose 1. Conclusions The safety profile of MEDI-547 does not support further clinical investigation in patients with advanced solid tumors.
MEDI-547; EphA2; Cancer therapy; Clinical trial; Relapsed/refractory solid tumors
YN968D1 (Apatinib) selectively inhibits phosphorylation of VEGFR-2 and tumor angiogenesis in mice model. The study was conducted to determine the maximum tolerated dose (MTD), safety profile, pharmacokinetic variables, and antitumor activity in advanced solid malignancies.
This dose-escalation study was conducted according to the Chinese State Food and Drug Administration (SFDA) recommendations in patients with advanced solid tumors to determine the MTD for orally administered apatinib. Doses of continuously administered apatinib were escalated from 250 mg. Treatment continued after dose-escalation phase until withdrawal of consent, intolerable toxicities, disease progression or death.
Forty-six patients were enrolled. Hypertension and hand-foot syndrome were the two dose-limiting toxicities noted at dose level of 1000 mg. MTD was determined to be 850 mg once daily. Pharmacokinetic analysis showed early absorption with a half-life of 9 hours. The mean half-life was constant over all dose groups. Steady-state conditions analysis suggested no accumulation during 56 days of once-daily administration. The most frequently observed drug-related adverse events were hypertension (69.5%, 29 grade 1-2 and 3 grade 3-4), proteinuria (47.8%, 16 grade 1-2 and 6 grade 3-4), and hand-foot syndrome (45.6%, 15 grade 1-2 and 6 grade 3-4). Among the thirty-seven evaluable patients, PR was noted in seven patients (18.9%), SD 24 (64.9%), with a disease control rate of 83.8% at 8 weeks.
The recommended dose of 750 mg once daily was well tolerated. Encouraging antitumor activity across a broad range of malignancies warrants further evaluation in selected populations.
ClinicalTrials.gov unique identifier: NCT00633490
Over the last seven years, seven targeted agents have been approved in the treatment of advanced or metastatic renal cell cancer, changing the therapeutic approach and prognosis of the disease dramatically. The latest agent with demonstrated efficacy is axitinib (Inlyta®). This new generation of tyrosine kinase agent differs from previously existing agents by its greater activity potency of inhibition of vascular endothelial growth factor-receptor (VEGFR1-3). This efficacy has been tested in phase II and III clinical trials. Axitinib is the only targeted agent that benefits from recommended titration, with intra-patient dose escalation. The toxicity profile of the drug is tolerable. This paper reviews the mechanism of action of axitinib, its metabolism, and its pharmacokinetic profile. Clinical data of efficacy and safety is also detailed. The agent has been integrated in the international therapeutic guidelines, as a standard in treatment of renal cell cancer patients, previously treated through antiangiogenic therapy.
axitinib; safety; efficacy; renal cell cancer
Human recombinant arginase I cobalt coupled to polyethylene glycol 5000 (HuArg I [Co]-PEG5000) achieved potent in vitro depletion of arginine from tissue culture medium and cytotoxicity to many cancer cell lines. The recombinant enzyme also produced tumor growth inhibition of hepatocellular carcinoma and pancreatic carcinoma xenografts. Although these results were promising, the therapeutic index was narrow. Toxicities were seen in normal cells in tissue culture. In vivo normal tissue injury occurred at doses twice the effective dose. The current study was conducted to define, in greater detail, the maximum tolerated dose (MTD), pharmacodynamics, and dose-limiting toxicities (DLTs) of twice-weekly intraperitoneal HuArg I [Co]-PEG5000 in Balb/c mice. Animal weight and survival were monitored, serum arginine levels measured, and complete blood cell counts, chemistries, necropsies, and histologies were performed. In addition, methods to ameliorate the HuArg I [Co]-PEG5000 adverse effects were tested. Supplemental l-citrulline was given concurrently with the arginase drug. The HuArg I [Co]-PEG5000 MTD in mice was 5 mg/kg twice weekly, and DLTs included weight loss and marrow necrosis. No other organ damage or changes in blood cell counts or chemistries were observed. Arginase reduced serum arginine levels from 60 µM to 4 to 6 µM. Supplemental l-citrulline given per os or daily subcutaneously reduced and delayed toxicities, and l-citrulline given twice daily subcutaneously completely prevented animal toxicities. On the basis of these results, we hypothesize that HuArg I [Co]-PEG5000, particularly with supplemental l-citrulline, may be an attractive therapeutic agent for argininosuccinate synthetase-deficient tumors.
The purpose of this study is to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and intracerebral distribution of a recombinant toxin (TP-38) targeting the epidermal growth factor receptor in patients with recurrent malignant brain tumors using the intracerebral infusion technique of convection-enhanced delivery (CED). Twenty patients were enrolled and stratified for dose escalation by the presence of residual tumor from 25 to 100 ng/ml in a 40-ml infusion volume. In the last eight patients, coinfusion of 123I-albumin was performed to monitor distribution within the brain. The MTD was not reached in this study. Dose escalation was stopped at 100 ng/ml due to inconsistent drug delivery as evidenced by imaging the coinfused 123I-albumin. Two DLTs were seen, and both were neurologic. Median survival after TP-38 was 28 weeks (95% confidence interval, 26.5–102.8). Of 15 patients treated with residual disease, two (13.3%) demonstrated radiographic responses, including one patient with glioblastoma multiforme who had a nearly complete response and remains alive >260 weeks after therapy. Coinfusion of 123I-albumin demonstrated that high concentrations of the infusate could be delivered >4 cm from the catheter tip. However, only 3 of 16 (19%) catheters produced intraparenchymal infusate distribution, while the majority leaked infusate into the cerebrospinal fluid spaces. Intracerebral CED of TP-38 was well tolerated and produced some durable radiographic responses at doses ≤100 ng/ml. CED has significant potential for enhancing delivery of therapeutic macromolecules throughout the human brain. However, the potential efficacy of drugs delivered by this technique may be severely constrained by ineffective infusion in many patients.
brain neoplasms; convection; drug delivery systems; epidermal growth factor receptor; immunotoxins
The use of bacteria in the regression of certain forms of cancer has been recognized for more than a century. Much effort, therefore, has been spent over the years in developing wild-type or modified bacterial strains to treat cancer. However, their use at the dose required for therapeutic efficacy has always been associated with toxicity problems and other deleterious effects. Recently, the old idea of using bacteria in the treatment of cancer has attracted considerable interest and new genetically engineered attenuated strains as well as microbial compounds that might have specific anticancer activity without side effects are being evaluated for their ability to act as new anticancer agents. This involves the use of attenuated bacterial strains and expressing foreign genes that encode the ability to convert non-toxic prodrugs to cytotoxic drugs. Novel strategies also include the use of bacterial products such as proteins, enzymes, immunotoxins and secondary metabolites, which specifically target cancer cells and cause tumor regression through growth inhibition, cell cycle arrest or apoptosis induction. In this review we describe the current knowledge and discuss the future directions regarding the use of bacteria or their products, in cancer therapy.
cancer therapy; anticancer agents from microbial sources; drug development; Pseudomonas aeruginosa; azurin; multi-targeting drugs in cancer therapy