Population pharmacodynamic study of amonafide: a Cancer and Leukemia Group B study

Photochemical Reactivity of Naphthol-Naphthalimide Conjugates and Their Biological Activity

Quinone methide precursors 1a–e, with different alkyl linkers between the naphthol and the naphthalimide chromophore, were synthesized. Their photophysical properties and photochemical reactivity were investigated and connected with biological activity. Upon excitation of the naphthol, Förster resonance energy transfer (FRET) to the naphthalimide takes place and the quantum yields of fluorescence are low (Φ_F ≈ 10⁻²). Due to FRET, photodehydration of naphthols to QMs takes place inefficiently (Φ_R ≈ 10⁻⁵). However, the formation of QMs can also be initiated upon excitation of naphthalimide, the lower energy chromophore, in a process that involves photoinduced electron transfer (PET) from the naphthol to the naphthalimide. Fluorescence titrations revealed that 1a and 1e form complexes with ct-DNA with moderate association constants K_a ≈ 10⁵–10⁶ M⁻¹, as well as with bovine serum albumin (BSA) K_a ≈ 10⁵ M⁻¹ (1:1 complex). The irradiation of the complex 1e@BSA resulted in the alkylation of the protein, probably via QM. The antiproliferative activity of 1a–e against two human cancer cell lines (H460 and MCF 7) was investigated with the cells kept in the dark or irradiated at 350 nm, whereupon cytotoxicity increased, particularly for 1e (>100 times). Although the enhancement of this activity upon UV irradiation has no imminent therapeutic application, the results presented have importance in the rational design of new generations of anticancer phototherapeutics that absorb visible light.

N-acetyltransferase: the practical consequences of polymorphic activity in man

Over the years, numerous studies have supported the premise that individuals possessing the "slow acetylator" phenotype are more at risk from developing drug side-effects. Most prominent amongst these reports are those concerned with hepatotoxicity and peripheral neuropathy following treatment with isoniazid, lupus-like symptoms during procainamide therapy and experiencing hypersensitivity reactions to the various sulphonamide derivatives. Similarly, "slow acetylators" undergoing heavy exposure to arylamines and related carcinogens are more likely to develop bladder cancer. Contrariwise, there appears a slight risk of "rapid acetylators" developing pancreatic tumours.Other therapeutic agents for which polymorphic N-acetylation plays a minor role in their metabolism have been investigated but any impact of this metabolic difference on clinical efficacy or associated toxicity is still under question. In the search for clues as to the underlying aetiology, patient groups with many disease states have been examined for association with differences in N-acetylation and the majority have provided data that could be interpreted as equivocal. Studies have given contradictory, often opposing, results, calculated risk factors that are (perhaps) just significant but certainly not high, and patients within the cohorts who are always exceptions. Undoubtedly, other as yet unappreciated factors are at play.

l,8-Naphthalimide based DNA intercalators and anticancer agents. A systematic review from 2007 to 2017

In this review, we describe a detailed investigation about the structural variations and relative activity of 1,8-naphthalimide based intercalators and anticancer agents. The 1,8-naphthalimides binds to the DNA via intercalation, and exert their antitumor activities through Topoisomerase I/II inhibition, photoinduced DNA damage or related mechanism. Here, our discussion focused on works published over the last ten years (2007-2017) related to therapeutic applications, in the order of cancer treatment followed by other properties of 1,8-naphthalimides. In preparing for this review, we considered that several seminal reviews have appeared over the last fifteen years and focused on closely related subjects, however, none of them is exhaustive.

UNBS5162 inhibits the proliferation of human A549 non-small-cell lung cancer cells by promoting apoptosis

Background

Lung cancer is one of the most frequently diagnosed malignancies in the world, thus developing novel anticancer reagents for lung cancer treatment is critical.

Methods

We performed cell counting kit‐8 and cell colony formation assays to investigate the role of UNBS5162 in the proliferation of A549 cells. Invasion and migration assays were applied to study the inhibitory effect of UNBS5162 on non‐small cell lung cancer cells. To detect the effect of UNBS5162 on A549 cell apoptosis, Annexin‐V fluorescein isothiocyanate and propidium iodide staining methods were used. Protein expression was analyzed using Western blot assay.

Results

UNBS5162 not only inhibited proliferation but also decreased invasion and migration in A549 cells. Most cells were intact (96.93%) under control conditions, but the number of intact cells decreased (84.8%) after 24 hours of treatment with UNBS5162, and the number of early and late apoptotic cells significantly increased (P < 0.05). Anti‐apoptotic protein Bcl‐2 expression in the UNBS5162 group was significantly decreased (P < 0.05), and expression of proapoptotic proteins Bim, Bax, and active caspase‐3 were significantly increased (P < 0.05) compared to the control. In the PI3K signaling pathway, phospo‐AKT and phospo‐mTOR levels were significantly decreased (P < 0.05), while S6K and Cyclin D1 protein levels were significantly decreased in UNBS5162 treated A549 cells (P < 0.05).

Conclusion

These findings suggest that UNBS5162 could inhibit A549 cell proliferation and metastasis by inhibiting PI3K pathway mediated apoptosis.

Synthesis and study of antiproliferative, antitopoisomerase II, DNA-intercalating and DNA-damaging activities of arylnaphthalimides

A series of arylnaphthalimides were designed and synthesized to overcome the dose-limiting cytotoxicity of N-acetylated metabolites arising from amonafide, the prototypical antitumour naphthalimide whose biomedical properties have been related to its ability to intercalate the DNA and poison the enzyme Topoisomerase II. Thus, these arylnaphthalimides were first evaluated for their antiproliferative activity against two tumour cell lines and for their antitopoisomerase II in vitro activities, together with their ability to intercalate the DNA in vitro and also through docking modelization. Then, the well-known DNA damage response in Saccharomyces cerevisiae was employed to critically evaluate whether these novel compounds can damage the DNA in vivo. By performing all these assays we conclude that the 5-arylsubstituted naphthalimides not only keep but also improve amonafide's biological activities.

Design and synthesis of pyrido[3,2-α]carbazole derivatives and their analogues as potent antitumour agents

A series of pyrido[3,2-α]carbazole derivatives and their analogues have been prepared and evaluated for their antitumour activity against human lung cancer A549 cells and colon cancer HT29 cells. The intermediates 4a-4k are successfully synthesized from 1a-1k and ethyl 2-(3-bromopyridin-2-yl)acetate by Knoevenagel condensation and intramolecular Heck-type reaction, and this is a novel and efficient synthetic approach to the core scaffold of the target compounds. These target compounds have shown an interesting antitumour profile towards the tested cell lines with IC50 values ranging from 0.07 μM to 4.45 μM. Among all the compounds synthesized, 8 compounds show higher potency than R16, 12 compounds are as potent as R16, and 6 compounds are less potent than R16. The best compound 24 is 7 times and approximately 10 times as potent as R16 against A549 and HT29 cells, respectively.

Phase I trial of UNBS5162, a novel naphthalimide in patients with advanced solid tumors or lymphoma

OBJECTIVES

UNBS5162 is a novel naphthalimide that binds to DNA by intercalation and suppresses CXCL chemokine elaboration. A Phase I study of UNBS5162 was conducted to establish pharmacokinetics (PK), maximum tolerated dose (MTD), dose-limiting toxicity, safety and anti-tumor activity in patients with advanced solid tumors or lymphoma.

METHODS

UNBS5162 was administered in a 3 + 3 dose escalation scheme by intravenous infusion over 1 h weekly for 3 weeks of a 4-week cycle. Safety, serial serum PK and tolerability were captured throughout the study. Response Evaluation Criteria in Solid Tumors was utilized every 2 cycles to assess for anti-tumor response.

RESULTS

Twenty-four patients with metastatic carcinoma and 1 patient with lymphoma were treated at eight dose levels (18-234 mg/m(2)). All patients were evaluable for tolerability and toxicity. Grade 3 toxicities include nausea (n = 1), fatigue (n = 1) and anorexia (n = 1). Prolongation of QTc [Hodges] was observed in 6 cases (Gr 1 = 2; Gr 2 = 2; Gr 3 = 2). C(max) and area under the curve increased linearly with dose with a t(1/2) of 30-60 min. 16 patients completed 2 cycles of therapy, all with pharmacodynamics at 8 weeks.

CONCLUSIONS

The MTD or dose-limiting toxicity for UNBS5162 was not reached due to the magnitude of QTc prolongation at the highest dose of 234 mg/m(2)/week that led to study termination.

Amonafide: a future in treatment of resistant and secondary acute myeloid leukemia?

Development of the novel topoisomerase II inhibitor, amonafide, began almost 40 years ago. The drug was selected for further investigation owing to evidence of marked antineoplastic efficacy in preclinical models of cancer. When its usefulness in the treatment of various solid malignancies proved limited, focus was shifted to establishing its use as an antileukemic agent, specifically against secondary and treatment-associated acute myeloid leukemia (AML). While Phase I and II studies gave rise to hopes that amonafide might hold the key to treating older patients, including those with multidrug resistant, cytogenetically unfavorable secondary and treatment-associated AML, when used in combination with cytarabine, it failed to demonstrate a survival advantage over standard-of-care therapy in randomized studies. This article will outline the development of amonafide from the laboratory to the bedside and discuss the potential place that this agent has in the current management of AML.

UNBS5162, a novel naphthalimide that decreases CXCL chemokine expression in experimental prostate cancers

Several naphthalimides have been evaluated clinically as potential anticancer agents. UNBS3157, a naphthalimide that belongs to the same class as amonafide, was designed to avoid the specific activating metabolism that induces amonafide's hematotoxicity. The current study shows that UNBS3157 rapidly and irreversibly hydrolyzes to UNBS5162 without generating amonafide. In vivo UNBS5162 after repeat administration significantly increased survival in orthotopic human prostate cancer models. Results obtained by the National Cancer Institute (NCI) using UNBS3157 and UNBS5162 against the NCI 60 cell line panel did not show a correlation with any other compound present in the NCI database, including amonafide, thereby suggesting a unique mechanism of action for these two novel naphthalimides. Affymetrix genome-wide microarray analysis and enzyme-linked immunosorbent assay revealed that in vitro exposure of PC-3 cells to UNBS5162 (1 microM for 5 successive days) dramatically decreased the expression of the proangiogenic CXCL chemokines. Histopathology additionally revealed antiangiogenic properties in vivo for UNBS5162 in the orthotopic PC-3 model. In conclusion, the present study reveals UNBS5162 to be a pan-antagonist of CXCL chemokine expression, with the compound displaying antitumor effects in experimental models of human refractory prostate cancer when administered alone and found to enhance the activity of taxol when coadministered with the taxoid.

2,2,2-Trichloro-N-({2-[2-(dimethylamino)ethyl]-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin- 5-yl}carbamoyl)acetamide (UNBS3157), a Novel Nonhematotoxic Naphthalimide Derivative with Potent Antitumor Activity

Amonafide (1), a naphthalimide which binds to DNA by intercalation and poisons topoisomerase IIalpha, has demonstrated activity in phase II breast cancer trials, but has failed thus far to enter clinical phase III because of dose-limiting bone marrow toxicity. Compound 17 (one of 41 new compounds synthesized) is a novel anticancer naphthalimide with a distinct mechanism of action, notably inducing autophagy and senescence in cancer cells. Compound 17 (2,2,2-trichloro-N-({2-[2-(dimethylamino)ethyl]-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-5-yl}carbamoyl)acetamide (UNBS3157)) was found to have a 3-4-fold higher maximum tolerated dose compared to amonafide and not to provoke hematotoxicity in mice at doses that display significant antitumor effects. Furthermore, 17 has shown itself to be superior to amonafide in vivo in models of (i) L1210 murine leukemia, (ii) MXT-HI murine mammary adenocarcinoma, and (iii) orthotopic models of human A549 NSCLC and BxPC3 pancreatic cancer. Compound 17, therefore, merits further investigation as a potential anticancer agent.

Comparative analysis of xanafide cytotoxicity in breast cancer cell lines

Xanafide, a DNA-intercalating agent and topoisomerase II inhibitor, has previously demonstrated comparable cytotoxicity to the parent drug amonafide (NSC 308847). The current study was conducted to investigate further the anti-proliferative effects of xanafide in human breast cancer cell lines, in vitro and in vivo. The in vitro activity of xanafide against MCF-7, MDA-MB-231, SKBR-3 and T47D cell lines was compared to that of paclitaxel, docetaxel, gemcitabine, vinorelbine and doxorubicin. In MCF-7, xanafide demonstrated comparable total growth inhibition (TGI) concentrations to the taxanes and lower TGI values than gemcitabine, vinorelbine and doxorubicin. MCF-7 (oestrogen receptor (ER)+/p53 wild-type) was the most sensitive cell line to xanafide. MDA-MB-231 and SKBR-3 exhibited similar sensitivity to xanafide. T47 D (ER+/p53 mutated), showed no response to this agent. The in vivo activity of xanafide was further compared to that of docetaxel in MCF-7 and MDA-MB-231 cell lines using the hollow fibre assay. Xanafide was slightly more potent than docetaxel, at its highest dose in MCF-7 cell line, whereas docetaxel was more effective than xanafide in MDA-MB-231 cell line. Our results show that there is no relationship between sensitivity of these cell lines to xanafide and cellular levels of both isoforms of topoisomerase II and suggest that ER and p53 status and their crosstalk may predict the responsiveness or resistance of breast cancer patients to xanafide.

R16, a novel amonafide analogue, induces apoptosis and G2-M arrest via poisoning topoisomerase II

Amonafide, a naphthalimide derivative, although selected for exploratory clinical trials for its potent anticancer activity, has long been challenged by its unpredictable side effects. In the present study, a novel amonafide analogue, 2-(2-dimethylamino)-6-thia-2-aza-benzo-[def]-chrysene-1,3-diones (R16) was synthesized by substituting 5'-NH(2) of the naphthyl with a heterocyclic group to amonafide, with additional introduction of a thiol group. In a panel of various human tumor cell lines, R16 was more cytotoxic than its parent compound amonafide. It was also effective against multidrug-resistant cells. Importantly, the i.p. administration of R16 inhibited tumor growth in mice implanted with S-180 sarcoma and H(22) hepatoma. The molecular and cellular machinery studies showed that the R16 functions as a topoisomerase II (topo II) poison via binding to the ATPase domain of human topo IIalpha. The superior cytotoxicity of R16 to amonafide was ascribed to its potent effects on trapping topo II-DNA cleavage complexes. Moreover, using a topo II catalytic inhibitor aclarubicin, ataxia-telangiectasia-mutated (ATM)/ATM- and Rad3-related (ATR) kinase inhibitor caffeine and topo II-deficient HL-60/MX2 cells, we further showed that R16-triggered DNA double-strand breaks, tumor cell cycle arrest, and apoptosis were in a topo II-dependent manner. Taken together, R16 stood out by its improved anticancer activity, appreciable anti-multidrug resistance activities, and well-defined topo II poisoning mechanisms, as comparable with the parent compound amonafide. All these collectively promise the potential value of R16 as an anticancer drug candidate, which deserves further development.

The cancer and leukemia group B pharmacology and experimental therapeutics committee: a historical perspective

The Chemotherapy Committee of Cancer and Leukemia Group B (CALGB) was established in the mid-1970s to assemble a group of experts in cancer chemotherapy and pharmacology who could advise the CALGB disease committees about the optimal use of drugs in the fight against cancer and to provide quality assurance for the chemotherapy section of CALGB protocols. Chaired initially by Edward Henderson and then David Van Echo, the committee was also the repository of studies in diseases for which CALGB did not have a formal committee, such as testis cancer and sarcoma. In 1990, following the appointment of Richard Schilsky as Chair, the name of the committee was changed to the Pharmacology and Experimental Therapeutics (PET) Committee to reflect a more specific focus and scientific agenda (i.e., studies of chemotherapy pharmacology and development of new agents). Three PET Committee reference pharmacology laboratories (led by Merrill Egorin, Tony Miller, and Mark Ratain) were established to measure drug concentrations in biological fluids and to perform pharmacokinetic analyses. In addition, the PET Committee embarked on a number of multi-institution phase I studies. These phase I studies included studies of special populations, including the first prospective study of an anticancer agent (paclitaxel) in patients with hepatic dysfunction. In addition, the Committee studied a number of phase I combinations destined for phase II evaluation in disease-specific committees. Following Dr. Schilsky's election as CALGB Group Chair in 1994, Mark Ratain took over as Chair of the PET Committee and continued to emphasize population pharmacology as the primary theme of the Committee's research agenda. In addition, the PET Committee began to develop novel clinical trial designs, including the first completed randomized discontinuation trial of an antineoplastic agent. Most recently, the PET Committee has launched an ambitious research program in pharmacogenetics, facilitated in large part through the recruitment of Howard McLeod as Vice Chair. This area of research is a collaborative effort with the NIH Pharmacogenetics Research Network and has the potential to definitively address the hypothesis that germ line polymorphisms are a significant determinant of the toxicity and efficacy of anticancer therapy. It is anticipated that the results of the current studies will contribute significantly to the goal of individualizing cancer treatment.

Predicting drug response and toxicity based on gene polymorphisms

The sequencing of the human genome has allowed the identification of thousands of gene polymorphisms, most often single nucleotide polymorphims (SNP), which may play an important role in the expression level and activity of the corresponding proteins. When these polymorphisms occur at the level of drug metabolising enzymes or transporters, the disposition of the drug may be altered and, consequently, its efficacy may be compromised or its toxicity enhanced. Polymorphisms can also occur at the level of proteins directly involved in drug action, either when the protein is the target of the drug or when the protein is involved in the repair of drug-induced lesions. There again, these polymorphisms may lead to alterations in drug efficacy and/or toxicity. The identification of functional polymorphisms in patients undergoing chemotherapy may help the clinician prescribe the optimal drug combination or schedule and predict with more accuracy the response to these prescriptions. We have recorded in this review the polymorphisms that have been identified up till now in genes involved in anticancer drug activity. Some of them appear especially important in predicting drug toxicity and should be determined in routine before drug administration; this is the case of the most common variations of thiopurine methyltransferase for 6-mercaptopurine and of dihydropyrimidine dehydrogenase for fluorouracil. Other appear determinant for drug response, such as the common SNPs found in glutathione S-transferase P1 or xereoderma pigmentosum group D enzyme for the activity of oxaliplatin. However, confusion factors may exist between the role of gene polymorphisms in cancer risk or overall prognosis and their role in drug response.

A review and assessment of potential sources of ethnic differences in drug responsiveness

The International Conference on Harmonization (ICH) E5 guidelines were developed to provide a general framework for evaluating the potential impact of ethnic factors on the acceptability of foreign clinical data, with the underlying objective to facilitate global drug development and registration. It is well recognized that all drugs exhibit significant inter-subject variability in pharmacokinetics and pharmacologic response and that such differences vary considerably among individual drugs and depend on a variety of factors. One such potential factor involves ethnicity. The objective of the present work was to perform an extensive review of the world literature on ethnic differences in drug disposition and responsiveness to determine their general significance in relation to drug development and registration. A few examples of suspected ethnic differences in pharmacokinetics or pharmacodynamics were identified. The available literature, however, was found to be heterologous, including a variety of study designs and research methodologies, and most of the publications were on drugs that were approved a long time ago.

Pharmacogenetics of the arylamine N-acetyltransferases

The arylamine N-acetyltransferases (NATs) are involved in the metabolism of a variety of different compounds that we are exposed to on a daily basis. Many drugs and chemicals found in the environment, such as those in cigarette smoke, car exhaust fumes and in foodstuffs, can be either detoxified by NATs and eliminated from the body or bioactivated to metabolites that have the potential to cause toxicity and/or cancer. NATs have been implicated in some adverse drug reactions and as risk factors for several different types of cancers. As a result, the levels of NATs in the body have important consequences with regard to an individual's susceptibility to certain drug-induced toxicities and cancers. This review focuses on recent advances in the molecular genetics of the human NATs.

Polymorphisms of metabolizing enzymes and transporter proteins involved in the clearance of anticancer agents

BACKGROUND

The efficacies and toxicities of anticancer agents vary greatly among patients. This is attributable to the activities of drug-metabolizing enzymes and membrane transporters, primarily determined by polymorphisms of the functions of genes encoding these proteins.

DESIGN

We reviewed the available literature on drug-metabolizing enzymes and membrane transporters, especially their physiological functions, genetic and functional polymorphisms, and involvement in metabolism, pharmacokinetics and toxicity of anticancer agents.

RESULTS

Nine enzymes metabolizing anticancer agents have been shown to have genetic polymorphisms: dihydropyrimidine dehydrogenase, cytochrome P450, NAD(P)H:quinone oxidoreductase 1, N-acetyltransferase 2, thiopurine methyltransferase, glutathione S-transferase, and uridine diphosphate glucuronosyltransferase. Decreased activities of these proteins can cause not only inherited metabolic disorders, but also extraordinarily severe toxicity in cancer patients given chemothearpy. Transporter proteins mediate cellular uptake and secretion of organic anions and cations. These proteins have recently been shown to play critical roles in the clearance of anticancer agents, although relations between patients' genetics backgrounds and the clinical significance of drug actions are poorly understood.

CONCLUSIONS

Further studies should be focused on dosing and selection of anticancer agents, based on the type and extent of metabolic variation among individuals, in order to avoid adverse reactions and therapeutic failure.

Validity of an ELISA for N-acetyltransferase-2 (NAT2) phenotyping

A competitive antigen ELISA was previously developed for NAT2 phenotyping, using caffeine as the probe drug. The ELISA phenotypes by measuring the ratio of 5-acetamido-6-amino-3-methyluracil (AAMU) and 1-methylxanthine (1X) after transformation of 5-acetamido-6-formylamino-3-methyluracil (AFMU) to AAMU, in contrast to capillary electrophoresis high-pressure liquid chromatography (HPLC) which phenotype by measuring the AFMU/1X ratio. The ELISA phenotyping was previously determined in 30 samples and correlated well with phenotypes determined by capillary electrophoresis (29/30). The correlation was extended with the standard HPLC methodology by expanding the data set by 146 in order to test the validity of the ELISA methodology. The correlation with HPLC in this larger sample size was 96%; whereas the correlation between the two methods for determination of 1X was high (r(2)=0.90), that for determination of AAMU by ELISA and AFMU by HPLC was low (r(2)=0.53). The poor correlation between the two methodologies could not be attributed to the age of urine samples, nor to a significant decomposition of AFMU in the body prior to collection of the urine sample. The addition of a simple caffeine metabolite extraction method, originally developed for HPLC analysis of metabolites, to the ELISA phenotyping protocol produced a methodology with absolute correlation to the standard HPLC method.

Phase I and pharmacokinetic study of LU79553, a DNA intercalating bisnaphthalimide, in patients with solid malignancies

PURPOSE

To determine the maximum-tolerated dose and characterize the pharmacokinetic behavior of LU79553, a novel bisnaphthalimide antineoplastic agent, when administered as a daily intravenous infusion for 5 days every 3 weeks.

PATIENTS AND METHODS

Patients with advanced solid malignancies received escalating doses of LU79553. Plasma sampling and urine collections were performed on both days 1 and 5 of the first course.

RESULTS

Thirty patients received 105 courses of LU79553 at doses ranging from 2 to 24 mg/m(2)/d. Proximal myopathy, erectile dysfunction, and myelosuppression precluded the administration of multiple courses at doses above 18 mg/m(2)/d. These toxicities were intolerable in two of six patients after receiving three courses at the 24-mg/m(2)/d dose level. At the 18-mg/m(2)/d dose, one of six patients developed febrile neutropenia and grade 2 proximal myopathy after three courses of LU79553. The results of electrophysiologic, histopathologic, and ultrastructural studies supported a drug-induced primary myopathic process. A patient with a platinum- and taxane-resistant papillary serous carcinoma of the peritoneum experienced a partial response lasting 22 months. Pharmacokinetics were dose-independent, optimally described by a three-compartment model, and there was modest drug accumulation over the 5 days of treatment.

CONCLUSION

Although no dose-limiting events were noted in the first two courses of LU79553, cumulative muscular toxicity precluded repetitive treatment with LU79553 at doses above 18 mg/m(2)/d, which is the recommended dose for subsequent disease-directed evaluations. The preliminary antitumor activity noted is encouraging, but the qualitative and cumulative nature of the principal toxicities, as well as the relatively small number of patients treated repetitively, mandate that rigorous and long-term toxicologic monitoring be performed in subsequent evaluations of this unique agent.

Pharmacogenetics and cancer chemotherapy

Cancer chemotherapy is limited by significant inter-individual variations in responses and toxicities. Such variations are often due to genetic alterations in drug metabolising enzymes (pharmacokinetic polymorphisms) or receptor expression (pharmacodynamic polymorphisms). Pharmacogenetic screening prior to anticancer drug administration may lead to identification of specific populations predisposed to drug toxicity or poor drug responses. The role of polymorphisms in specific enzymes, such as thiopurine S-methyltransferases (TPMT), dihydropyrimidine dehydrogenase (DPD), aldehyde dehydrogenases (ALDH), glutathione S-transferases (GST), uridine diphosphate glucuronosyl-transferases (UGTs) and cytochrome P450 (CYP 450) enzymes in cancer therapy are discussed in this review.

An ECOG phase II study of amonafide in unresectable or recurrent carcinoma of the head and neck (PB390). Eastern Cooperative Oncology Group

The purpose of this study was to determine the efficacy and toxicity of amonafide in unresectable or recurrent head and neck cancer and to determine if the degree of toxicity with amonafide correlated with the acetylator phenotype of the patient. Thirty patients were registered on the study and received amonafide, 300 mg/m2, over two hours each day for five consecutive days every 21 days. There was one partial response (3%) which lasted four months. The dose-limiting toxicity was myelosuppression. Acetylator phenotype was determined prior to treatment using HPLC to quantitate caffeine metabolites in urine samples after administration of caffeine. This pharmacokinetic evaluation was performed in 21 patients and revealed that (17/21) 81% of the patients were slow acetylators and 19% of the patients were rapid acetylators. No association was found between acetylator phenotype and toxicity in our patient population. Based on this study, it appears that amonafide given at 300 mg/m2 for 5 consecutive days every 21 days is not active in squamous cell carcinoma of the head and neck, and that acetylator status does not correlate with toxicity.