CD8+ T Cells Impact Rising PSA in Biochemically Relapsed Cancer Patients Using Immunotherapy Targeting Tumor-Associated Antigens.

The management of men with prostate cancer (PCa) with biochemical recurrence following local definitive therapy remains controversial. Early use of androgen deprivation therapy (ADT) leads to significant side effects. Developing an alternative, clinically effective, and well-tolerated therapy remains an unmet clinical need. INO-5150 is a synthetic DNA therapy that includes plasmids encoding for prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA), and INO-9012 is a synthetic DNA plasmid encoding for interleukin-12 (IL-12). This phase 1/2, open-label, multi-center study enrolled men with PCa with rising PSA after surgery and/or radiation therapy. Patients were enrolled into one of four treatment arms: arm A, 2 mg of INO-5150; arm B, 8.5 mg of INO-5150; arm C, 2 mg of INO-5150 + 1 mg of INO-9012; and arm D, 8.5 mg of INO-5150 + 1 mg of INO-9012. Patients received study drug with electroporation on day 0 and on weeks 3, 12, and 24, and they were followed for up to 72 weeks. Sixty-two patients were enrolled. Treatment was well tolerated. 81% (50/62) of patients completed all visits. 85% (53/62) remained progression-free at 72 weeks. PSA doubling time (PSADT) was increased when assessed in patients with day 0 PSADT ≤12 months. Immunogenicity was observed in 76% (47/62) of patients by multiple assessments. Analysis indicated that CD38 and perforin co-positive CD8 T cell frequency correlated with attenuated PSA rise (p = 0.05, n = 50).

A Phase I trial of the kinesin spindle protein (Eg5) inhibitor AZD4877 in patients with solid and lymphoid malignancies.

BACKGROUND: This Phase I study assessed the safety and maximum tolerated dose (MTD) of the kinesin spindle protein inhibitor AZD4877 in patients with relapsed/refractory solid tumors and lymphoma. METHODS: In this multicenter study, a standard 3 + 3 dose-escalation design was used. AZD4877 was given as an intravenous infusion on days 1, 4, 8 and 11 of each 21-day cycle. Responses were assessed with CT scans +/- PET after 6 and 12 weeks, then every 12 weeks while on therapy. An additional four patients with lymphoma were enrolled at the MTD. RESULTS: 29 patients were enrolled and 22 patients received at least one dose of AZD4877 and were evaluable for safety. The MTD was 11 mg. Dose-limiting toxicity was neutropenia (n = 2 patients, 15 mg cohort). The most common adverse events were grade 1/2 fatigue, nausea, neutropenia and dyspnea. AZD4877 exposure generally increased with dose, with mean elimination half-life approximately 16 h at the MTD. Pharmacodynamic analyses demonstrated moderate correlation between plasma drug concentrations at 6 or 24 h and monoaster formation in peripheral blood mononuclear cells (PBMCs). CONCLUSIONS: AZD4877 is generally well-tolerated with pharmacodynamic evidence of target inhibition in circulating PBMCs.

Phase II study to assess the efficacy, safety and tolerability of the mitotic spindle kinesin inhibitor AZD4877 in patients with recurrent advanced urothelial cancer.

BACKGROUND: AZD4877 is a potent inhibitor of the mitotic spindle kinesin, Eg5. Early-phase clinical studies in a broad range of cancers showed that AZD4877 is well tolerated. This Phase II study evaluated the efficacy, safety and pharmacokinetics (Cmax) of AZD4877 in patients with previously treated advanced urothelial cancer (ClinicalTrials.gov identifier NCT00661609). PATIENTS AND METHODS: AZD4877 25 mg was administered once-weekly for 3 weeks of each 4-week cycle until disease progression, death, unacceptable toxicity or withdrawal. The primary objective was to determine the objective response rate (RECIST). Recruitment was to be halted if ≤ 2 of the first 20 evaluable patients achieved an objective tumor response. Cmax was assessed on days 1 and 8 of cycle 1. RESULTS: None of the first 20 patients evaluable for efficacy achieved an objective response; enrollment was therefore halted. During this initial analysis, a further 21 patients were recruited. Overall, 39 patients were evaluable for efficacy, including one with confirmed partial response (PR) and seven patients with stable disease for ≥ 8 weeks (including one unconfirmed PR). The most commonly reported treatment-related adverse events (TRAEs) were neutropenia (22 patients), fatigue (12), leukopenia (7) and constipation (6); the most commonly reported grade ≥ 3 TRAE was neutropenia (21). Four patients had serious TRAEs. On days 1 and 8, the geometric mean Cmax of AZD4877 was 138 ng/ml (CV = 75 %) and 144 ng/ml (CV = 109 %), respectively. CONCLUSIONS: AZD4877 was generally tolerable in patients with advanced urothelial cancer. Given the limited clinical efficacy, further development of AZD4877 in urothelial cancer is not planned.

Vaccines for HPV-associated diseases.

Human papillomavirus (HPV) infection represents a significant global health concern owing to its role in the etiology of conditions ranging from benign low-grade lesions to cancers of the cervix, head and neck, anus, vagina, vulva, and penis. Prophylactic vaccination programs, primarily targeting adolescent girls, have achieved dramatic reductions in rates of HPV infection and cervical cancer in recent years. However, there is a clear demand for a strategy to manage the needs of the many people who are already living with persistent HPV infection and/or HPV-associated conditions. Unlike prophylactic vaccines, which act to prevent HPV infection, therapeutic vaccination presents an opportunity to induce cellular immunity against established HPV infections and lesions and prevent progression to cancer. Several HPV vaccines are undergoing clinical development, using a range of platforms. Peptide- or protein-based vaccines, vector-based vaccines, whole-cell vaccines, and nucleic acid vaccines each offer relative merits and limitations for the delivery of HPV antigens and the subsequent generation of targeted immune responses. There has been particular interest in DNA-based vaccines, which elicit both cellular and humoral immune responses to provide long-lasting immunity. DNA vaccines offer several practical advantages over other vaccine platforms, including the potential for rapid and scalable manufacturing, targeting of many different antigens, and potential for repeat boosting. Furthermore, unlike vectored approaches, DNA vaccines are thermostable over extended time periods, which may enable shipping and storage. Several delivery strategies are available to address the main challenge of DNA vaccines, namely their relatively low transfection efficiency. We review the latest clinical data supporting the development of DNA vaccines and reflect on this exciting prospect in the management of HPV-related disease.

Changing incentives to ACCELERATE drug development for paediatric cancer.

BACKGROUND: More effective incentives are needed to motivate paediatric oncology drug development, uncoupling it from dependency on adult drug development. Although the current European and North-American legislations aim to promote drug development for paediatrics and rare diseases, children and adolescents with cancer have not benefited as expected from these initiatives and cancer remains the first cause of death by disease in children older than one. Drug development for childhood cancer remains dependent on adult cancer indications and their potential market. The balance between the investment needed to execute a Paediatric Investigation Plan (PIP) in Europe and an initial Paediatric Study Plan (iPSP) in the US, coupled with the potential financial reward has not been sufficiently attractive to incite the pharmaceutical industry to develop drugs for rare indications such as childhood cancer. METHODS: We propose changes in the timing and nature of the rewards within the European Paediatric Medicine Regulation (PMR) and Regulation on Orphan Medicinal Products (both currently under review), which would drive earlier initiation of paediatric oncology studies and provide incentives for drug development specifically for childhood indications. RESULTS: We suggest modifying the PMR to ensure mechanism-of-action driven mandatory PIP and reorganization of incentives to a stepwise and incremental approach. Interim and final deliverables should be defined within a PIP or iPSP, each attracting a reward on completion. A crucial change would be the introduction of the interim deliverable requiring production of paediatric data that inform the go/no-go decisions on whether to take a drug forward to paediatric efficacy trials. CONCLUSION: Additionally, to address the critical gap in the current framework where there is a complete lack of incentives to promote paediatric-specific cancer drug development, we propose the introduction of early rewards in the Orphan Regulation, with a variant on the US-Creating Hope Act and its priority review vouchers.

Interim Results of a Phase 1/2 Open-Label Study of INO-3107 for HPV-6 and/or HPV-11-Associated Recurrent Respiratory Papillomatosis.

OBJECTIVE: To evaluate the safety, immunogenicity, and efficacy of INO-3107, a DNA immunotherapy designed to elicit targeted T-cell responses against human papillomavirus (HPV) types 6 and 11, in adult patients with recurrent respiratory papillomatosis (RRP; NCT04398433). METHODS: Eligible patients required ≥2 surgical interventions for RRP in the year preceding dosing. INO-3107 was administered by intramuscular (IM) injection followed by electroporation (EP) on weeks 0, 3, 6, and 9. Patients underwent surgical debulking within 14 days prior to first dose, with office laryngoscopy and staging at screening and weeks 6, 11, 26, and 52. Primary endpoint was safety and tolerability, as assessed by treatment-emergent adverse events (TEAEs). Secondary endpoints included frequency of surgical interventions post-INO-3107 and cellular immune responses. RESULTS: An initial cohort of 21 patients was enrolled between October 2020 and August 2021. Fifteen (71.4%) patients had ≥1 TEAE; 11 (52.4%) were Grade 1, and 3 (14.3%) were Grade 3 (none treatment related). The most frequently reported TEAE was injection site or procedural pain (n = 8; 38.1%). Sixteen (76.2%) patients had fewer surgical interventions in the year following INO-3107 administration, with a median decrease of 3 interventions versus the preceding year. The RRP severity score, modified by Pransky, showed improvement from baseline to week 52. INO-3107 induced durable cellular responses against HPV-6 and HPV-11, with an increase in activated CD4 and CD8 T cells and CD8 cells with lytic potential. CONCLUSION: The data suggest that INO-3107 administered by IM/EP is tolerable and immunogenic and provides clinical benefit to adults with RRP. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:3087-3093, 2023.

ACCELERATE - Five years accelerating cancer drug development for children and adolescents.

Rapid evaluation and subsequent regulatory approval of new drugs are critical to improving survival and reducing long-term side-effects for children and adolescents with cancer. The international multi-stakeholder organisation ACCELERATE was created to advance the timely investigation of new anti-cancer drugs. ACCELERATE has enhanced communication and understanding between academia, industry, patient advocates and regulators. It has promoted a mechanism-of-action driven drug development approach and developed Paediatric Strategy Forums. These initiatives have facilitated prioritisation of medicinal products and a focused and sequential strategy for drug development where there are multiple potential agents. ACCELERATE has championed the early assessment of promising drugs in adolescents through their inclusion in adult early phase trials. ACCELERATE has strongly supported alignment between the European Medicines Agency and the US Food and Drug Administration and identification of unmet medical needs through multi-stakeholder collaboration. Early engagement between all stakeholders in the development of new drugs is critical. Innovative clinical trial designs are required, necessitating early discussion with sponsors and regulators. Amplifying the patient advocate voice through inclusion across the drug development continuum will lead to better, patient-centric trials. By these means, children and adolescents with cancer can maximally and rapidly benefit from innovative products to improve outcomes and reduce burdensome sequelae.

Dactinomycin and vincristine toxicity in the treatment of childhood cancer: a retrospective study from the Children's Oncology Group.

BACKGROUND: Dactinomycin (AMD) and vincristine (VCR) have been used for the treatment of childhood cancer over the past 40 years but evidence-based dosing guidance is lacking. METHODS: Patient AMD and VCR dose and drug-related adverse event (AE) information from four rhabdomyosarcoma (RMS) and two Wilms tumor (WT) studies were assembled. Statistical modeling was used to account for differences in AE data collection across studies, develop rate models for grade 3/4 CTCAE v3 hepatic- (AMD) and neuro- (VCR) toxicity, assess variation in toxicity rates over age and other factors, and predict toxicity risk under current dosing guidelines. RESULTS: For the same dose/body size, AMD toxicity rates were higher in patients <1 year than older patients and VCR toxicity rates increased with age. The statistical model provided estimates for AMD and VCR toxicity risk under current dosing schedules and indicated that patients of smaller body size were at lower risk of VCR toxicity than larger patients of the same age. The rate of AMD toxicity was highest early in treatment and was lower in patients who tolerated initial AMD without toxicity. CONCLUSION: The observed decrease in AMD toxicity rate with cumulative dose may indicate sensitivity in a subgroup of patients while the observed increase in VCR toxicity risk with age may indicate changing sensitivity to VCR. Current dosing practices result in a fairly uniform toxicity profile within age group. However, PK/PD studies should be done to provide further provide further information on best dosing guidelines.

Toxicity and pharmacokinetics of actinomycin-D and vincristine in children and adolescents: Children's Oncology Group Study ADVL06B1.

Actinomycin-D and vincristine are cytotoxic drugs commonly used to treat cancers in children. This prospective study assessed pharmacokinetic variability and toxicity of these drugs in children. Blood samples were collected in 158 patients. Actinomycin-D or vincristine concentrations were quantified using high-performance liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were estimated using non-compartmental methods. Target toxicities were collected prospectively. Actinomycin-D pharmacokinetics (n = 52 patients) were highly variable. The median (coefficient of variation, CV%) area under the concentration-time curve (AUC) was 332 ng/mL·h. (110%); clearance was 4.6 L/h/m2 (90%); half-life was 25 h (60%). No patient met the defined criteria for myelosuppression. In multivariate analysis, none of the demographic nor pharmacokinetic parameters was predictors of acute hepatotoxicity. Vincristine pharmacokinetics (n = 132 patients) demonstrated substantial variability. The median (CV%) AUC was 78 ng/mL·h (98%); clearance was 17.2 L/h/m2 (67%); half-life was 14.6 h (73%). In multivariate analysis, the effect of increasing age for a given BSA was an increase in neuropathy while the effect of increasing BSA for a given age was a decrease in neuropathy. Conclusion: Pharmacokinetics of both drugs were highly variable. For actinomycin-D, there was no correlation between demographic or pharmacokinetic parameters and target toxicities. For vincristine, the correlations of age and BSA and neuropathy are confounded by the correlation between age and BSA in children and the ability to ascertain neuropathy in infants. Variability may be attributed to dose reductions and capped doses for both drugs. Investigation of BSA-based dosing in young children is warranted to decrease variability of exposure.

Phase 1 study of safety, tolerability and immunogenicity of the human telomerase (hTERT)-encoded DNA plasmids INO-1400 and INO-1401 with or without IL-12 DNA plasmid INO-9012 in adult patients with solid tumors.

BACKGROUND: Human telomerase reverse transcriptase (hTERT) is frequently classified as a 'universal' tumor associated antigen due to its expression in a vast number of cancers. We evaluated plasmid DNA-encoded hTERT as an immunotherapy across nine cancer types. METHODS: A phase 1 clinical trial was conducted in adult patients with no evidence of disease following definitive surgery and standard therapy, who were at high risk of relapse. Plasmid DNA encoding one of two hTERT variants (INO-1400 or INO-1401) with or without plasmid DNA encoding interleukin 12 (IL-12) (INO-9012) was delivered intramuscularly concurrent with the application of the CELLECTRA constant-current electroporation device 4 times across 12 weeks. Safety assessments and immune monitoring against native (germline, non-mutated, non-plasmid matched) hTERT antigen were performed. The largest cohort of patients enrolled had pancreatic cancer, allowing for additional targeted assessments for this tumor type. RESULTS: Of the 93 enrolled patients who received at least one dose, 88 had at least one adverse event; the majority were grade 1 or 2, related to injection site. At 18 months, 54.8% (51/93) patients were disease-free, with median disease-free survival (DFS) not reached by end of study. For patients with pancreatic cancer, the median DFS was 9 months, with 41.4% of these patients remaining disease-free at 18 months. hTERT immunotherapy induced a de novo cellular immune response or enhanced pre-existing cellular responses to native hTERT in 96% (88/92) of patients with various cancer types. Treatment with INO-1400/INO-1401±INO-9012 drove hTERT-specific IFN-γ production, generated hTERT-specific CD4+ and CD8+ T cells expressing the activation marker CD38, and induced hTERT-specific activated CD8 +CTLs as defined by cells expressing perforin and granzymes. The addition of plasmid IL-12 adjuvant elicited higher magnitudes of cellular responses including IFN-γ production, activated CD4+ and CD8+ T cells, and activated CD8+CTLs. In a subset analysis of pancreatic cancer patients, the presence of immunotherapy-induced activated CD8+ T cells expressing PD-1, granzymes and perforin correlated with survival. CONCLUSIONS: Plasmid DNA-encoded hTERT/IL-12 DNA immunotherapy was well-tolerated, immune responses were noted across all tumor types, and a specific CD8+ phenotype increased by the immunotherapy was significantly correlated with survival in patients with pancreatic cancer.

Kinesin motor proteins as targets for cancer therapy.

The process of mitosis is a validated point of intervention in cancer therapy and a variety of anti-mitotic drugs are successfully being used in the clinic. To date, all approved antimitotics target the spindle microtubules, thus interfering with spindle dynamics, leading to mitotic arrest and apoptosis. While effective, these drugs are also associated with a variety of side effects, including neurotoxicity. In recent years, mitotic kinesins have attracted significant attention in the search for novel, alternative mitotic drug targets. Due to their specific function in mitosis, targeting these proteins creates an opportunity for the development of more selective antimitotics with an improved side effect profile. In addition, kinesin inhibitors may overcome resistance to microtubule targeting drugs. Drug discovery efforts in this area have initially focused on the plus-end directed kinesin spindle protein (KSP) and a variety of compounds are currently undergoing clinical testing.

Approaches to clear residual chemotherapeutics from indwelling catheters in children with cancer.

OBJECTIVES: To develop a method for drug dosing and pharmacokinetic (PK) sampling in children with cancer from a single indwelling central venous catheter that minimized drug contamination. METHODS: A benchtop system was designed to simulate dosing and clearing actinomycin-D (AMD) and vincristine (VCR) from central venous catheters. The authors evaluated the effects of flush volume, composition and pH, timed drug instillation, and number of blood-draw return cycles on residual drug concentrations. A proof-of-principle study was conducted in three pediatric patients with cancer with paired PK samples obtained by both central and peripheral catheters. RESULTS: Nearly complete removal of drug from the catheter was obtained after five blood-draw return cycles consisting of 5 mL of whole blood. Residual concentration of AMD was 0.18 ± 0.02 ng/mL or 0.16% of the initial infusion concentration. VCR exhibited lower propensity for catheter adsorption than AMD with residual concentrations undetectable after three blood-draw return cycles. In patients in which the clearance procedure was used, higher drug concentrations were generally observed from centrally cleared samples at most time points, but differences relative to peripherally obtained samples were not statistically significant for either AMD or VCR. Two of three patients had higher exposure for AMD based on PK samples obtained from central catheters, whereas exposure for VCR was similar for both sampling catheters in all patients. CONCLUSIONS: A reliable procedure to efficiently reduce AMD and VCR contamination during PK sampling has been established and is currently being used in a PK study being conducted by the Children's Oncology Group.

A Phase 1 Trial Assessing the Safety and Tolerability of a Therapeutic DNA Vaccination Against HPV16 and HPV18 E6/E7 Oncogenes After Chemoradiation for Cervical Cancer.

PURPOSE: This study assessed the safety and tolerability of therapeutic immunization against the human papillomavirus (HPV) viral oncoproteins E6 and E7 in patients with cervical cancer after chemoradiation. METHODS AND MATERIALS: MEDI0457 (INO-3112) is a DNA-based vaccine targeting E6 and E7 of HPV-16/18 that is coinjected with an IL-12 plasmid followed by electroporation with the CELLECTRA 5P device. At 2 to 4 weeks after chemoradiation, patients with newly diagnosed stage IB1-IVA (cohort 1) or persistent/recurrent (cohort 2) cervical cancers were treated with 4 immunizations of MEDI0457 every 4 weeks. The primary endpoints were incidence of adverse events and injection site reactions. Immune responses against HPV antigens were measured by ELISpot for interferon-γ (IFNγ), enzyme-linked immunosorbent assay for antibody responses and multiplexed immunofluorescence for immune cells in cervical biopsy specimens. RESULTS: Ten patients (cohort 1, n = 7; cohort 2, n = 3) with HPV16 (n = 7) or HPV18 (n = 3) cervical cancers received MEDI0457 after chemoradiation. Treatment-related adverse events were all grade 1, primarily related to the injection site. Eight of 10 patients had detectable cellular or humoral immune responses against HPV antigens after chemoradiation and vaccination: 6 of 10 patients generated anti-HPV antibody responses and 6 of 10 patients generated IFNγ-producing T cell responses. At the completion of chemoradiation and vaccination, cervical biopsy specimens had detectable CD8+ T cells and decreased PD-1+CD8+, PD-L1+CD8+, and PD-L1+CD68+ subpopulations. All patients cleared detectable HPV DNA in cervical biopsies by completion of chemoradiation and vaccination. CONCLUSIONS: Adjuvant MEDI0457 is safe and well tolerated after chemoradiation for locally advanced or recurrent cervical cancers, supporting further investigation into combining tumor-specific vaccines with radiation therapy.

Immune Therapy Targeting E6/E7 Oncogenes of Human Paillomavirus Type 6 (HPV-6) Reduces or Eliminates the Need for Surgical Intervention in the Treatment of HPV-6 Associated Recurrent Respiratory Papillomatosis.

: Background: Recurrent respiratory papillomatosis (RRP) is a rare disorder characterized by the generation of papillomas of the aerodigestive tract, usually associated with human papilloma virus (HPV) subtypes 6, 11. INO-3106 is a DNA plasmid-based immunotherapy targeting E6 and E7 proteins of HPV6, in order to create a robust immune T cell response. METHODS: Testing of INO-3016 in animal models confirmed immunogenicity of the DNA-based therapy. A single-site open-label Phase 1 study was initiated for patients with HPV6-positive RRP. Patients were dosed with INO-3106 with or without INO-9012, a DNA plasmid immunotherapy that encodes IL-12, delivered intramuscularly (IM) in combination with electroporation (EP) with the CELLECTRA® device. Patients received an escalating dose of INO-3106, 3 mg once and then 6 mg for three additional doses, each dose three weeks apart, with the third and fourth doses co-administered with INO-9012. The primary objective of the study was to evaluate the safety and tolerability of INO-3106 with and without INO-9012. The secondary objective was to determine cellular immune responses to INO-3106 with and without INO-9012. Exploratory objectives included preliminary clinical efficacy to the therapy. RESULTS: Three patients were enrolled in this study, of which two had RRP. Study therapy was well-tolerated, with no related serious adverse events and all related adverse events (AEs) were low-grade. Injection site pain was the most common related AE reported. Immunogenicity was evidenced by multiple immune assays showing engagement and expansion of an HPV6-specific cellular response, including cytotoxic T cells. Preliminary efficacy was demonstrated in patients with RRP in the form of reduction in need for surgical intervention for papilloma growth. Prior to intervention, both patients required surgical intervention approximately every 180 days. One patient demonstrated a greater than three-fold increase in surgery avoidance (584 days) and the other patient remains completely surgery-free as of the last contact at 915 days, a greater than 5-fold increase in surgery interval. CONCLUSION: INO-3106 with and without INO-9012 was well tolerated, immunogenic and demonstrated preliminary efficacy in patients with HPV6-associated RRP aerodigestive lesions. Further clinical study is indicated.

Population pharmacokinetic investigation of actinomycin-D in children and young adults.

Actinomycin-D is an antineoplastic agent that inhibits RNA synthesis by binding to guanine residues and inhibiting DNA-dependent RNA polymerase. Although actinomycin-D has been used to treat rhabdomyosarcoma and Wilms tumor for more than 40 years, the dose/exposure relationship is not well characterized. The objective of this study was to develop an initial population pharmacokinetic model to describe actinomycin-D disposition in children and young adults from which a prospective study could be designed. A total of 165 actinomycin-D plasma concentration measurements from 33 patients, aged 1.6 to 20.3 years, were used for the analysis. The data were analyzed using nonlinear mixed-effects modeling with the NONMEM software system. Age, weight, and gender were examined as covariates for the ability to explain interindividual variability in actinomycin-D pharmacokinetics. The final model was qualified via predictive check and nonparametric bootstrap procedures. A 3-compartment model with first-order elimination was chosen as the structural model. Allometric expressions incorporating weight were used to describe the effects of body size on actinomycin-D pharmacokinetics. Age and gender had no discernible effects on actinomycin-D pharmacokinetics in the population studied. The predictive check showed that the developed model was able to simulate data in close agreement with the actual study observations. The availability of an initial population pharmacokinetic model to describe actinomycin-D pharmacokinetics will facilitate the development of a large-scale clinical trial to study the actinomycin-D dose/exposure relationship in pediatric patients with rhabdomyosarcoma and Wilms tumor. The covariate analysis described by the current data set suggests that indices of body size captured via allometric expressions improve the partition of variation in actinomycin-D pharmacokinetics from this pilot data set. Relationships between pharmacokinetics and toxicity will be examined in future prospective studies in which children less than 1 year old will be enrolled.

A SAS-based solution to evaluate study design efficiency of phase I pediatric oncology trials via discrete event simulation.

Previous exploration of oncology study design efficiency has focused on Markov processes alone (probability-based events) without consideration for time dependencies. Barriers to study completion include time delays associated with patient accrual, inevaluability (IE), time to dose limiting toxicities (DLT) and administrative and review time. Discrete event simulation (DES) can incorporate probability-based assignment of DLT and IE frequency, correlated with cohort in the case of DLT, with time-based events defined by stochastic relationships. A SAS-based solution to examine study efficiency metrics and evaluate design modifications that would improve study efficiency is presented. Virtual patients are simulated with attributes defined from prior distributions of relevant patient characteristics. Study population datasets are read into SAS macros which select patients and enroll them into a study based on the specific design criteria if the study is open to enrollment. Waiting times, arrival times and time to study events are also sampled from prior distributions; post-processing of study simulations is provided within the decision macros and compared across designs in a separate post-processing algorithm. This solution is examined via comparison of the standard 3+3 decision rule relative to the "rolling 6" design, a newly proposed enrollment strategy for the phase I pediatric oncology setting.

Tyrosine kinase inhibitors in pediatric malignancies.

Tyrosine kinase inhibitors have been used to treat adult cancers for over a decade. Since the discovery of imatinib mesylate (STI-571, Gleevec; Novartis), tyrosine kinase inhibitors have ushered in a new age of targeted therapy. Although the United States Food and Drug Administration has approved several kinase inhibitors for use in adult cancers, currently only imatinib mesylate is approved for use in children with cancer. This review highlights the mechanisms of tyrosine kinase inhibition, the potential role of tyrosine kinase pathways in the treatment of pediatric cancers, and the current status of pediatric clinical investigation of a spectrum of tyrosine kinase inhibitors for the treatment of childhood cancer.

A sensitive and selective liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of actinomycin-D and vincristine in children with cancer.

We describe a selective and a highly sensitive assay for actinomycin-D (Act-D) and vincristine (VCR) in plasma employing high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) detection. The intraday precision (as defined by the coefficient of variation, CV) based on the standard deviation of replicates of quality control samples ranged from 4.9 to 7.5% and 6.5 to 11.3% with accuracy ranging from 90.7 to 98.1% and 91.2 to 103% for Act-D and VCR, respectively. The interday precision ranged from 7.2 to 10.0% and 11.3 to 13.0% and the accuracy ranged from 94.3 to 102% and 90.7 to 91.6% for Act-D and VCR, respectively. Stability studies showed that Act-D and VCR were stable both during the assay procedure and long-term storage. The lower limit of quantitation (LLOQ) for both Act-D and VCR was 0.05 ng/ml. The analytical method showed excellent sensitivity, precision, and accuracy. This method is robust and is being successfully employed in a pharmacokinetic study of these agents in children with cancer, and is expected to support several ongoing and future pediatric trials.

Pediatric phase I trials in oncology: an analysis of study conduct efficiency.

PURPOSE: To determine the efficacy and safety of pediatric phase I oncology trials in the era of dose-intensive chemotherapy and to analyze how efficiently these trials are conducted. METHODS: Phase I pediatric oncology trials published from 1990 to 2004 and their corresponding adult phase I trials were reviewed. Dose escalation schemes using fixed 30% dose increments were studied to theoretically determine whether trials could be completed utilizing fewer patients and dose levels. RESULTS: Sixty-nine pediatric phase I oncology trials enrolling 1,973 patients were identified. The pediatric maximum-tolerated dose (MTD) was strongly correlated with the adult MTD (r = 0.97). For three-fourths of the trials, the pediatric and adult MTD differed by no more than 30%, and for more than 85% of the trials, the pediatric MTD was less than or equal to 1.6 times the adult MTD. The median number of dose levels studied was four (range, two to 13). The overall objective response rate was 9.6%, the likelihood of experiencing a dose-limiting toxicity was 24%, and toxic death rate was 0.5%. CONCLUSION: Despite the strong correlation between the adult and pediatric MTDs, more than four dose levels were studied in 40% of trials. There appeared to be little value in exploring dose levels greater than 1.6 times the adult MTD. Limiting pediatric phase I trials to a maximum of four doses levels would significantly shorten the timeline for study conduct without compromising safety.

A liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of actinomycin-D and vincristine in children with cancer.

Actinomycin-D (Act-D) and vincristine (VCR) are cytotoxic agents commonly used in the treatment of pediatric cancers. To date, there are few published methods on quantifying Act-D or VCR and no published methods on quantifying the two drugs together. We present a methodology for the simultaneous quantification of Act-D and VCR in human plasma using liquid chromatography-tandem mass spectrometry (LC/MS/MS) detection. Following solid phase extraction, plasma samples were separated and analyzed using electrospray ionization (ESI). The lower limit of quantitation (LLOQ) for both Act-D and VCR was 0.5 ng/ml. The analytical accuracy for detection of both Act-D and VCR was > or = 90%. The analytical precision, as estimated by the coefficient of variation was < or = 6% for Act-D and < or = 11% for VCR. Given the prevalence of the use of the two drugs as combination therapy in a variety of pediatric oncological indications, the small sample volume requirements and the assay sensitivity, this methodology is expected to support several ongoing and future pediatric trials.