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.

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.

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.

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).

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.

A Systematic Literature Review of Adverse Events Associated with Systemic Treatments Used in Advanced Soft Tissue Sarcoma.

This systematic literature review describes adverse events (AEs) among patients with soft tissue sarcoma (STS) who received second-line or later anticancer therapies. Searches were conducted in PubMed, EMBASE, and Cochrane Central Register of Controlled Trials for studies of adults with advanced or metastatic STS who received systemic anticancer therapy before enrollment in a randomized-controlled trial of pazopanib, another targeted cancer agent, or cytotoxic chemotherapy. Of 204 publications identified, seven articles representing six unique studies met inclusion criteria. Additional safety results for pazopanib were identified on ClinicalTrials.gov. Hematologic toxicities were common with all therapies evaluated (pazopanib, trabectedin, dacarbazine ± gemcitabine, gemcitabine ± docetaxel, cyclophosphamide, and ifosfamide). Studies differed in AE type, timing of assessment, and outcomes reported, although patient populations and AE assessment timing were relatively similar for pazopanib and trabectedin. AEs that were more common with trabectedin than pazopanib were anemia, neutropenia, nausea/vomiting, and elevations in aspartate aminotransferase and alanine aminotransferase. An AE that was more common with pazopanib than trabectedin was anorexia. Only the pazopanib study reported AE frequencies versus placebo. A planned meta-analysis was not feasible, as there was no common comparator. More well-designed studies that include common comparators are needed for comparison of safety effects among treatments for STS.

A phase II trial to evaluate the efficacy of fostamatinib in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL).

PURPOSE: To assess the safety and efficacy of fostamatinib in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL). EXPERIMENTAL DESIGN: Relapsed or refractory DLBCL patients originally received the oral spleen tyrosine kinase inhibitor, fostamatinib in a two-arm, randomised, double-blinded manner at either 100 mg twice a day (BID) or 200 mg BID until disease progression or unacceptable toxicity. The primary objective was to assess the overall response rate (ORR). Preliminary analysis showed limited efficacy and all subsequent patients were treated at 200 mg BID. Previously randomised patients were unblinded and given the opportunity to receive 200 mg BID. RESULTS: Sixty-eight patients were treated (47 at 200 mg BID, 21 at 100 mg BID). Cell of origin analysis showed 58% germinal B-cell (GCB) origin, 30% activated B-cell (ABC) origin and 12% with an intermediate cell of origin signature. The most common treatment-related adverse events of all patients were diarrhoea (21% total, 6% grade 3/4), nausea (19% total, 3% grade 3/4), and, fatigue (18% total, 9% grade 3/4). The ORR rate was 3% across both arms and clinical benefit (≥ stable disease) was achieved for 13% of all patients. The cell of origin for patients with clinical benefit was GCB (4 patients), intermediate (4 patients) or unknown (1 patient). None of the patients with clinical benefit had ABC genotype. CONCLUSIONS: While fostamatinib was generally well tolerated in this patient population, efficacy at these doses and schedule was poor. Unlike data with other B-cell antigen receptor pathway inhibitors, responses were not observed in the ABC genotype.

Antitumor activity in RAS-driven tumors by blocking AKT and MEK.

PURPOSE: KRAS is the most commonly mutated oncogene in human tumors. KRAS-mutant cells may exhibit resistance to the allosteric MEK1/2 inhibitor selumetinib (AZD6244; ARRY-142886) and allosteric AKT inhibitors (such as MK-2206), the combination of which may overcome resistance to both monotherapies. EXPERIMENTAL DESIGN: We conducted a dose/schedule-finding study evaluating MK-2206 and selumetinib in patients with advanced treatment-refractory solid tumors. Recommended dosing schedules were defined as MK-2206 at 135 mg weekly and selumetinib at 100 mg once daily. RESULTS: Grade 3 rash was the most common dose-limiting toxicity (DLT); other DLTs included grade 4 lipase increase, grade 3 stomatitis, diarrhea, and fatigue, and grade 3 and grade 2 retinal pigment epithelium detachment. There were no meaningful pharmacokinetic drug-drug interactions. Clinical antitumor activity included RECIST 1.0-confirmed partial responses in non-small cell lung cancer and low-grade ovarian carcinoma. CONCLUSION: Responses in KRAS-mutant cancers were generally durable. Clinical cotargeting of MEK and AKT signaling may be an important therapeutic strategy in KRAS-driven human malignancies (Trial NCT number NCT01021748).

Risk assessment of drug interaction potential and concomitant dosing pattern on targeted toxicities in pediatric cancer patients.

This investigation evaluated the impact of potential drug interactions on the incidence of reported toxicities seen with common dosing patterns in children with cancer, with the intent of being able to screen and reduce the incidence of adverse drug reactions (ADRs) in the future. Toxicity reported in pediatric cancer patients treated at the Children's Hospital of Philadelphia from 2004 to 2010 were abstracted from a cancer tumor registry and merged with drug order profiles from the medical record system. Analysis datasets were created in SAS and permutation algorithms were used to identify pairwise drug combinations associated with specific toxicity occurrence. Relative risk of toxicity based on dosing pattern was assessed via comparison to control patients. A total of 326 of 1,713 patients (19%) had reportable toxicities. Neutrophil count decreases and alanine aminotransferase increases represented the highest occurring, corresponding to 28.8% and 31.9% prevalence among patients reporting toxicity, respectively. Of coadministered drug pairs, acetaminophen-diphenhydramine occurred most frequently; however, methotrexate-vincristine was the highest occurring pair linked to a single toxicity (hepatotoxicity). Toxicity was highly associated with the diagnoses of leukemia (52.1%) or neuroblastoma (28.5%). Comparison of the dosing interval (≤30 versus >30 min) suggested that risk of toxicity can be associated with the timing of coadministration, with ≤30 min increasing the risk of hepatotoxicity with fentanyl-midazolam and methotrexate-midazolam combinations. Knowledge of drug interactions in children with cancer may help reduce the incidence of ADRs by providing pharmacotherapy options that may reduce the likelihood of toxicity.

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.

Modeling and simulation approaches to evaluate pharmacokinetic sampling contamination from central venous catheters in pediatric pharmacokinetic studies of actinomycin-D: a report from the children's oncology group.

BACKGROUND: The binding of drugs to catheters can be a source variation in dosing chemotherapeutics. Drug contamination from the dosing central venous line (CVL) can impact the reporting of pharmacokinetic (PK) results and analysis. Peripheral venipuncture avoids binding complications from the CVL but dissuades patients from enrolling. Our group has developed a catheter clearing procedure to minimize the extent of contamination so that dosing and sampling from the CVL can ensue, promoting patient willingness to participate in phase I pediatric oncology trials. OBJECTIVES: To develop a population pharmacokinetic model of actinomycin-D (AMD) in children with cancer incorporating expressions for drug contamination from PK samples obtained via indwelling CVLs and to evaluate the efficiency of a catheter clearing procedure in removing contamination as well as the impact of contamination on PK results. METHODS: A dataset of 199 AMD plasma concentration measurements from 36 patients (age 1.6-20.3 years) was analyzed using nonlinear mixed-effects modeling. Quantitative modeling approaches, including baseline contamination model, covariate model, and catheter clearance model, were evaluated to describe catheter contamination. Monte Carlo simulations mimicking a prospective study in children with cancer were performed to assess the performance of the final model and impact of catheter contamination on PK reporting. RESULTS: The PK of AMD was best described by a linear 3-compartment model with first-order elimination. A baseline contamination model including a contamination factor proportional to the model-predicted concentration for samples obtained from central catheters was chosen as the most parsimonious and accurate among competing models. The final model parameters were allometrically scaled to a 70 kg person. The estimated mean parameter values were 11 L/h, 5.79, 24.2, 490 L, 17.7, and 42.8 L/h for total clearance, central volume of distribution, peripheral volume 1, peripheral volume 2, inter-compartmental clearance 1, and inter-compartmental clearance 2, respectively. The proportional contamination factor was 19.3 % immediately post-drug administration and decreased at a first-order rate of 0.0932 h(-1). Simulations precisely re-estimated kinetic parameters with catheter contamination adjustment. Large uncertainty and poor estimation were observed when contamination was ignored. CONCLUSIONS: Drug contamination from sampling catheter can impact AMD PK results and should be accounted for in the analysis. We provide a framework for evaluating catheter contamination and guidance on adjustment in the PK model.

A reliable and safe method of collecting blood samples from implantable central venous catheters for determination of plasma gentamicin concentrations.

STUDY OBJECTIVE: To evaluate the extent of agreement between plasma gentamicin concentrations determined from samples collected by using implantable subcutaneous central venous catheters (ports) with the push-pull method and those collected by finger lancet punctures in children with febrile neutropenia. DESIGN: Prospective, randomized study. SETTING: University-affiliated, tertiary care hospital. PATIENTS: Sixty-two children with cancer who had single- or double-lumen ports and who received gentamicin for treatment of febrile neutropenia between February 2008 and October 2009. INTERVENTION: One blood sample was collected from the port by using the push-pull method at the same time one blood sample was collected by finger lancet puncture for determination of plasma gentamicin concentrations. MEASUREMENTS AND MAIN RESULTS: Forty-four pairs of samples were available for assessment of agreement, and 43 were available for pharmacokinetic analysis. Agreement between plasma gentamicin concentrations determined from blood samples from ports and finger lancet punctures was assessed by the intraclass correlation coefficient (ICC), Bland-Altman analysis, and comparison of simulated dosage adjustments. Changes in port patency were monitored for 1 week after port sampling. Differences in simulated dosage adjustments calculated by using either the port or finger lancet puncture samples that differed by greater than 20% were considered clinically significant. Agreement between the 44 finger lancet puncture and port sample pairs was excellent (ICC 0.991, 95% confidence interval 0.984-0.995). Port plasma gentamicin concentrations were 4.7% lower than those concentrations determined in blood from finger lancet punctures. The observed limits of agreement ranged from -20.5% to 11%. Differences in dosage adjustments calculated by using port and finger lancet puncture plasma gentamicin concentrations were not clinically significant in 38 (88%) of 43 cases. No changes in port patency were observed in the week after port sampling. CONCLUSION: The push-pull method of blood sampling is a reliable and safe option for determining plasma gentamicin concentrations in children with ports.

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.

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 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.

Shortening the timeline of pediatric phase I trials: the rolling six design.

PURPOSE: To shorten the study conduct timeline of pediatric phase I oncology trials by employing a novel trial design. METHODS: A comparison of the traditional 3 + 3 patients per cohort, phase I trial design with a novel, rolling six design was performed by using discrete event simulation. The rolling six design allows for accrual of two to six patients concurrently onto a dose level based on the number of patients currently enrolled and evaluable, the number experiencing dose-limiting toxicity (DLT), and the number still at risk of developing a DLT. Clinical trial simulations (n = 1,000) were based on historical data and were performed using SAS 9.1.3 (SAS Institute, Cary, NC). Study timelines and patient numbers were determined for each design, and safety was assessed as a function of the number of DLTs observed. RESULTS: In twelve completed historical studies, the median time to study completion was 452 days (range, 220 to 606 days); number of evaluable participants enrolled was 22 (range, 11 to 33), and DLTs occurring per study was three (range, 0 to 5). In 1,000 study simulations, in which the average time to new patient accrual was 10 days, the average +/- standard deviation (SD) time to study completion was 294 +/- 75 days for the rolling six design versus 350 +/- 84 days for the 3 + 3 design, whereas the number of DLTs per study was the same (average +/- SD, 3.3 +/- 1.1 v 3.2 +/- 1.1 for the rolling six and 3 + 3 designs, respectively). CONCLUSION: The rolling six design may significantly decrease the duration of pediatric phase I studies without increasing the risk of toxicity. The design will be tested prospectively in upcoming Children's Oncology Group phase I trials.

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.

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.

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.