Comparison of the Efficacy of K-File, Canal Brush Technique, and Sonic Irrigation Technique in the Retrievability of Calcium Hydroxide and Metapex Intracanal Medicaments from Root Canals: An In vitro Cone-Beam Computed Tomography Analysis

Background and Objectives:

At present, none of the routinely used irrigating agents and activation techniques were able to completely remove the Ca(OH)₂ intracanal medicament placed inside the root canal system during endodontic therapy. With this as the background, the aim of this study was to achieve complete removal of Ca(OH)₂ when mixed with two different vehicles, using various irrigant activation techniques such as K-file, canal brush technique, and sonic irrigation technique, from the root canals of extracted human teeth.

Materials and Methods:

Seventy-two mandibular premolar teeth with straight single root canal were selected and filled either with oil-based Metapex or calcium hydroxide powder mixed with distilled water and were activated using different activation techniques such as K-file, canal brush, and sonic MM1500 and NaOCl alone. Volumetric analysis was performed utilizing cone-beam computed tomography.

Results:

None of the irrigants used were able to completely remove Ca(OH)₂ from root canal. Sonic MM1500 showed significant removal efficacy than K-file, canal brush technique, and NaOCl for both aqueous-based and oil-based calcium hydroxide.

Conclusion:

Sonic MM1500 performed better than K-file, canal brush technique, and NaOCl in removing both Metapex and Ca(OH)₂ powder. Regardless of the vehicles and agitation technique used, the remnants of Ca(OH)₂ were present on all thirds of the canal walls.

Use of extubation bundle including modified spontaneous breathing trial (SBT) to reduce the rate of reintubation, among preterm neonates ≤ 30 weeks

BACKGROUND

Respiratory support in the form of mechanical ventilation is a crucial intervention in premature neonates, with respiratory problems. However, prolonged mechanical ventilation and endotracheal intubation may be associated with major adverse effects. The ideal time for extubation is based on clinical and laboratory parameters assessed at the time of planned extubation. However, such parameters are not very objective, which makes extubation in NICUs a trial-and-error approach.

OBJECTIVE

This work was done to assess the use of extubation bundle including modified spontaneous breathing trial (SBT) (10 minutes) to reduce the rate of reintubation, among preterm neonates≤30 weeks who were mechanically ventilated and extubated to non-invasive ventilation in the NICU, Women's Wellness and Research Center (WWRC), Hamad Medical Corporation (HMC), Doha, Qatar.

METHODS

A prospective study based on the collection of data regarding preterm neonates≤30 weeks gestation admitted to the NICU, Women's Wellness and Research Center (WWRC), from January, 2015 to December, 2017, who were subjected to mechanical ventilation (MV) and extubation. When the clinical team decides a newborn is ready for extubation based on the extubation bundle, a modified SBT (10 min) is used.

RESULTS

This study included 465 premature babies from 24-≤30 weeks recruited in the NICU, Women's Wellness and Research Center (WWRC). Extubation bundle with modified SBT was able to predict success of extubation with 95% sensitivity and 90.4% Positive Predictive Value (PPV) in the gestational age (GA) group 24 -≤27 weeks (245) and 95.3% sensitivity and 90% PPV in the GA group > 27 -≤30 weeks (220). As expected, successfully extubated babies had a higher GA and weighed more at extubation, compared to babies who required re-intubation.

CONCLUSION

We recommend the extubation bundle with modified SBT prior to elective extubation to be used in predicting successful extubation in premature babies. Guidelines for extubation among premature babies are needed in order to reduce unnecessary exposure to adverse effects of mechanical ventilation.

The Evaluation of Dentin Microhardness After Use of 17% EDTA, 17% EGTA, 10% Citric Acid, MTAD Used as Chelating Agents Combined With 2.5% Sodium Hypochlorite After Rotary Instrumentation: An In Vitro SEM Study

Introduction

The smear layer removed during root canal instrumentation enables penetration of irrigant solution and adhesion of root canal sealants providing a fluid tight seal of obturated root canals, necessitating its removal. The aim of the study was to compare the effect of smear layer removal by 17% Ethylene diamine tetraacetic acid (EDTA), 17% Ethylene glycol tetraacetic acid (EGTA),10% Citric acid and (MTAD solution) a Mixture of tetracycline isomer, an acid and a detergent applied as final rinse , when used along with 2.5% (NaOCl) Sodium hypochlorite and its effect on dentin microhardness.

Materials and Methods

Sixty single-rooted human mandibular premolars with minimum curvature (<5°) were instrumented using rotary instrumentation till apical enlargement size 35 RaCe file 0.04 taper. During instrumentation, the canals were irrigated with 2-mL 2.5% NaOCl. After instrumentation, teeth were rinsed with distilled water and were divided into 5 groups (n = 12) according to final rinse for 1 min with 5-mL 17% EDTA followed by 5-mL 2.5% NaOCl (group 1, control group), 17% EGTA (group 2), MTAD solution (group 3), 10% citric acid (group 4), and 17% EDTA (group 5). Teeth were split through the groove prepared, and one-half of specimen were evaluated for smear layer removal using scanning electron microscopy. A score system was followed to evaluate the images and comparisons among groups were performed using Kruskal-Wallis one-way analysis. Multiple comparisons were performed using Mann-Whitney U test. The other half was evaluated for dentin microhardness using Vickers microhardness testing machine. Microhardness values were statistically analyzed using parametric one-way analysis of variance test.

Conclusion

Irrigation regimen following the use of 2.5% NaOCl during instrumentation followed by application of 5-mL 17% EDTA solution for 1 min resulted in efficient smear layer removal and less decrease in dentin microhardness compared with 17% EGTA, 10% citric acid, and MTAD solution.

Clinical Pharmacokinetics and Pharmacodynamics of Atezolizumab in Metastatic Urothelial Carcinoma

Atezolizumab, a humanized immunoglobulin G1 (IgG1) monoclonal antibody targeting human programmed death-ligand 1 (PD-L1), is US Food and Drug Administration (FDA) approved in metastatic urothelial carcinoma (MUC) and is being investigated in various malignancies. This analysis based upon 906 patients from two phase I and one phase II MUC studies, is the first report of the clinical pharmacokinetics (PK) and pharmacodynamics (PD) of atezolizumab. Atezolizumab exhibited linear PK over a dose range of 1-20 mg/kg, including the labeled 1,200 mg dose. The clearance, volume of distribution, and terminal half-life estimates from population pharmacokinetic (PopPK) analysis of 0.200 L/day, 6.91 L, and 27 days, respectively, were as expected for an IgG1. Exposure-response analyses did not identify statistically significant relationships with either objective response rate or adverse events of grades 3-5 or of special interest. None of the statistically significant covariates from PopPK (body weight, gender, antitherapeutic antibody, albumin, and tumor burden) would require dose adjustment.

Time-to-Event Analysis of Polatuzumab Vedotin-Induced Peripheral Neuropathy to Assist in the Comparison of Clinical Dosing Regimens

Polatuzumab vedotin, an antibody-drug conjugate containing monomethyl auristatin E, was associated with an incidence of grade ≥2 peripheral neuropathy (PN) of 55-72% in patients with indolent non-Hodgkin lymphoma in a phase II study, when dosed 1.8-2.4 mg/kg every 3 weeks until progression or for a maximum of 17 cycles. To quantify the correlation of conjugate exposure and treatment duration with PN risk, a time-to-event model was developed using data from phase I and II studies. The model suggested that PN risk increased with conjugate exposure and treatment cycles, and a trend for increased risk with body weight and albumin concentration. When capping the treatment duration to six to eight cycles, the risk ratio of a dose of 2.4 mg/kg vs. 1.8 mg/kg was ≥1.29; the predicted incidence of grade ≥2 PN at 1.8-2.4 mg/kg dose levels was 17.8-37.2%, which is comparable with other antimicrotubule agents for lymphoma treatment.

Abstract P4-21-26: Population pharmacokinetics (PK) and exposure-response (E-R) analysis of trastuzumab emtansine (T-DM1) in patients with HER2+ metastatic breast cancer (MBC) who have received at least two prior regimens of HER2-directed therapy

Background:

TH3RESA was a Phase III randomized study to evaluate the efficacy and safety of trastuzumab emtansine (T-DM1) compared to treatment of physician's choice (TPC) in patients with HER2+ MBC who have progression after at least two regimens of HER2-directed therapy. Population pharmacokinetic (PK) and exposure-response (E-R) analyses were performed to characterize T-DM1 PK as well as E-R relationship for key efficacy and safety endpoints in the population.

Methods:

Post-hoc analysis based on historical T-DM1 population PK models was performed to assess whether PK is consistent with historical data. E-R analyses with OS and PFS were conducted using Cox proportional hazard (CPH) models with exposure metrics (model-predicted Cycle 1 Cmin and AUCss) included in the model. Logistic regression models were used for binary endpoints of overall response rate (ORR) and key safety endpoints with exposure metrics included as continuous variable only. To supplement the E-R analysis for OS and PFS, case matching analyses were conducted to compare OS and PFS in the lowest exposure quartile (Q1) vs. higher exposure quartiles (Q2-4) to their corresponding matched control.

Results:

Historical T-DM1 population PK model well described T-DM1 PK in TH3RESA study. In CPH analyses with OS and PFS, hazard ratios (HR) of both efficacy endpoints consistently decreased with increasing T-DM1 exposure. The E-R relationship is supported by case matching analyses, where T-DM1 treated patients were stratified by model-predicted Cycle 1 Cmin. HRs of OS and PFS for patients at Q2−4 versus their matched TPC patients (HR (95%CI): 0.58 (0.44, 0.78) for OS; 0.47 (0.36, 0.62) for PFS) were numerically smaller than that of T-DM1 treated patients at Q1 versus their corresponding matched TPC patients (HR (95%CI): 0.96 (0.63, 1.47) for OS; 0.92 (0.64, 1.32) for PFS). For ORR, an E-R trend was also noted. On the other hand, no E-R relationship was identified with key safety endpoints.

HR for Quartile of Cmin Before and After Adjusting for Risk Factors QuartileUnadjusted HR (95% CI)Adjusted HR (95% CI)OSQ11.14 (0.832, 1.55)0.886 (0.64, 1.23) Q20.828 (0.6, 1.14)0.685 (0.493, 0.952) Q30.532 (0.374, 0.757)0.559 (0.391, 0.798) Q40.352 (0.238, 0.521)0.405 (0.272, 0.603)PFSQ10.852 (0.63, 1.15)0.831 (0.614, 1.12) Q20.635 (0.463, 0.872)0.619 (0.451, 0.85) Q30.428 (0.3, 0.609)0.442 (0.31, 0.632) Q40.237 (0.158, 0.357)0.258 (0.171, 0.389)

HR for Quartile of AUCss Before and After Adjusting for Risk Factors QuartileUnadjusted HR (95% CI)Adjusted HR (95% CI)OSQ11.07 (0.782, 1.47)0.774 (0.555, 1.08) Q20.651 (0.464, 0.912)0.567 (0.402, 0.801) Q30.662 (0.472, 0.929)0.736 (0.523, 1.04) Q40.406 (0.280, 0.588)0.458 (0.315, 0.667)PFSQ10.69 (0.505, 0.941)0.657 (0.481, 0.897) Q20.66 (0.479, 0.908)0.681 (0.494, 0.940) Q30.524 (0.377, 0.730)0.545 (0.390, 0.760) Q40.235 (0.155, 0.355)0.253 (0.167, 0.383)

Conclusion:

T-DM1 PK in TH3RESA patient population is similar to historical data. Although an E-R relationship was observed for efficacy, the results need to be interpreted with caution given the potential confounding association between risk factor and PK. No E-R relationship was observed for the safety endpoints examined.

Citation Format: Chen S-C, Polhamus D, Riggs M, French J, Wang X, Smitt M, Hoersch S, Strasak A, Chernyukhin N, Quartino A, Jin J, Girish S, Li C. Population pharmacokinetics (PK) and exposure-response (E-R) analysis of trastuzumab emtansine (T-DM1) in patients with HER2+ metastatic breast cancer (MBC) who have received at least two prior regimens of HER2-directed therapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-26.

Integrated Two-Analyte Population Pharmacokinetic Model for Antibody-Drug Conjugates in Patients: Implications for Reducing Pharmacokinetic Sampling

An integrated pharmacokinetics (PK) model that simultaneously describes concentrations of total antibody (Tab) and antibody‐conjugated monomethyl auristatin E (acMMAE) following administration of monomethyl auristatin E (MMAE)‐containing antibody–drug conjugates (ADCs) was developed based on phase I PK data with extensive sampling for two ADCs. Two linear two‐compartment models that shared all parameters were used to describe the PK of Tab and acMMAE, except that the deconjugation rate was an additional clearance pathway included in the acMMAE PK model compared to Tab. Further, the model demonstrated its ability to predict Tab concentrations and PK parameters based on observed acMMAE PK and various reduced or eliminated Tab PK sampling schemes of phase II data. Thus, this integrated model allows for the reduction of Tab PK sampling in late‐phase clinical development without compromising Tab PK characterization.

Sealing ability of three root-end filling materials prepared using an erbium: Yttrium aluminium garnet laser and endosonic tip evaluated by confocal laser scanning microscopy

Aims:

(1) To compare the sealing ability of mineral trioxide aggregate (MTA), Biodentine, and Chitra-calcium phosphate cement (CPC) when used as root-end filling, evaluated under confocal laser scanning microscope using Rhodamine B dye. (2) To evaluate effect of ultrasonic retroprep tip and an erbium:yttrium aluminium garnet (Er:YAG) laser on the integrity of three different root-end filling materials.

Materials and Methods:

The root canals of 80 extracted teeth were instrumented and obturated with gutta-percha. The apical 3 mm of each tooth was resected and 3 mm root-end preparation was made using ultrasonic tip (n = 30) and Er:YAG laser (n = 30). MTA, Biodentine, and Chitra-CPC were used to restore 10 teeth each. The samples were coated with varnish and after drying, they were immersed in Rhodamine B dye for 24 h. The teeth were then rinsed, sectioned longitudinally, and observed under confocal laser scanning microscope.

Statistical Analysis Used:

Data were analyzed using one-way analysis of variance (ANOVA) and a post-hoc Tukey's test at P < 0.05 (R software version 3.1.0).

Results:

Comparison of microleakage showed maximum peak value of 0.45 mm for Biodentine, 0.85 mm for MTA, and 1.05 mm for Chitra-CPC. The amount of dye penetration was found to be lesser in root ends prepared using Er:YAG laser when compared with ultrasonics, the difference was found to be statistically significant (P < 0.05).

Conclusions:

Root-end cavities prepared with Er:YAG laser and restored with Biodentine showed superior sealing ability compared to those prepared with ultrasonics.

Abstract P5-18-24: Population pharmacokinetics of trastuzumab emtansine, a HER2-targeted antibody-drug conjugate, in patients with HER2-positive metastatic breast cancer: clinical implications of the effect of various covariates

Background: Trastuzumab emtansine (T-DM1) is a HER2-targeted antibody-drug conjugate composed of the humanized monoclonal antibody trastuzumab, the potent cytotoxic agent DM1 (a microtubule inhibitor), and a stable thioether linker. To estimate typical pharmacokinetic (PK) parameter values and interpatient variability, a population PK model for T-DM1 was previously developed from 1 phase 1 (0.3 to 4.8 mg/kg in qw or q3w regimens) and 2 phase 2 (3.6 mg/kg q3w) trials (Gupta, J Clin Pharmacol 2012). The model reported here has been updated with additional data from 2 randomized trials (phase 2 TDM4450g and phase 3 EMILIA, 3.6 mg/kg q3w). Another phase 2 trial (TDM4688g) was used for external validation of the model. The effect of demographic and pathophysiological covariates on the PK of T-DM1 was explored to better understand the clinical factors that might affect exposure and clinical outcome for individual patients.

Methods: For the current analysis, 9934 T-DM1 serum concentration-time data points from 671 patients were simultaneously fitted using NONMEM® software. T-DM1 concentration-time data to date are best described using a 2-compartment linear model. All relevant and plausible covariates likely to have an effect on T-DM1 systemic exposure, or likely to have clinical relevance, were explored for possible correlation with the key T-DM1 PK parameters of clearance (CL) and central volume of distribution (Vc). These covariates include those related to demographics, renal and hepatic function, disease status, and treatment history.

Results: The estimated CL for T-DM1 is 0.68 L/day, Vc is 3.13 L, and the terminal half-life is 3.94 days. Interindividual variability (IIV) of the base model is 25.6% and 17.5% for CL and Vc, respectively. Patients with greater body weight, sum of longest dimension of target lesions, serum concentration of shed HER2 extracellular domain, and aspartate aminotransferase concentrations, as well as patients with lower serum albumin and baseline trastuzumab concentrations, have statistically faster CL. Patients with greater body weight also have statistically larger Vc. Incorporation of these covariates (P&lt;0.001 by likelihood ratio test) decreased IIV of CL and Vc to 19.1% and 11.7%, respectively. All covariates together explain 44.4% and 55.8% of IIV in CL and Vc, respectively. The model sensitivity analysis suggests that a patient with a statistically significant PK covariate value at the 5th or 95th percentile of the population will have a &lt;20% difference in cumulative exposure (as represented by area under the T-DM1 concentration-time curve) compared with a typical patient with a median covariate value.

Conclusions: A relatively small IIV for the estimated T-DM1 PK parameters of CL and Vc was observed. None of the evaluated covariates had a clinically meaningful magnitude of effect on T-DM1 exposure (&lt;20% difference for patients with 5th and 95th percentiles vs patients with median value of covariates) that would justify a further dose adjustment. The body weight–based dose of 3.6 mg/kg q3w without further correction for other factors is considered appropriate in ongoing clinical trials.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-18-24.

P1-12-13: Comparative Pharmacokinetics (PK) of Trastuzumab Emtansine (T-DM1) in Patients Who Have or Who Have Not Received Prior Treatment for Human Epidermal Growth Factor 2 (HER2)-Positive Metastatic Breast Cancer (MBC)

Background: T-DM1, an antibody-drug conjugate composed of trastuzumab, a stable linker, and the cytotoxic agent DM1, is in development for the treatment of HER2−positive cancers. Single-agent T-DM1 3.6 mg/kg every 3 weeks (q3w) has demonstrated clinical activity in 2 phase II studies (TDM4258g and TDM4374g) in patients with pretreated HER2−positive MBC. The efficacy and safety of T-DM1 vs trastuzumab + docetaxel was investigated in patients with no prior MBC treatment in the randomized phase II study TDM4450g/BO21976. Here we report the PK of T-DM1 from that study and compare these data with those from studies that enrolled pretreated patients.

Methods: In all 3 studies, PK parameters, including maximum concentration (Cmax), area under the concentration-time curve (AUC), terminal half-life (t½), steady-state volume of distribution (Vss), and clearance (CL) were estimated by noncompartmental analysis (NCA) for serum T-DM1, serum total trastuzumab (conjugated and unconjugated), and plasma DM1. The effects of baseline trastuzumab and HER2 extracellular domain (ECD) concentration on T-DM1 exposure were explored and the relationship between T-DM1 exposure and clinical response (objective response rate [ORR] and progression-free survival [PFS]) was modeled.

Results: T-DM1 PK from evaluable patients enrolled in 3 studies are shown in Table 1. No significant correlations were observed between efficacy (as measured by ORR) and T-DM1 exposure (AUC, Cmax) after administration of T-DM1 to pretreated patients; efficacy-exposure analyses (ORR and PFS) for previously untreated patients will be presented. Patients with measurable concentrations of trastuzumab at baseline had a greater AUC during cycle 1; however, this did not impact ORR. Baseline circulating HER2 ECD concentrations also had no effect on ORR for pretreated patients. The impact of baseline trastuzumab and HER2 ECD concentrations on ORR and PFS in previously untreated patients will be presented.

The effect of ketoprofen in chronic periodontitis: A clinical double-blind study

Background:

The objective of this double-blind clinical trial was to evaluate the effects of the nonsteroidal anti-inflammatory drug (NSAID), ketoprofen, on patients with chronic periodontitis.

Materials and Methods:

Two similar local drug delivery preparations of a poloxamen gel containing 1.5% ketoprofen and a placebo were indigenously prepared for this purpose. Ten subjects aged 33-55 years with moderate to severe chronic periodontitis were recruited and were monitored for a period of 90 days. Three sites in each patient (total 30 sites) with a probing pocket depth of 5-8 mm were selected and divided randomly into three groups: 1) group A: scaling and rootplaning (SRP) + drug A; 2) group B: SRP + drug B; and 3) group C: SRP. Clinical parameters and blood smear (from intracrevicular blood) were assessed to determine the differential count and Arneth index. All parameters were assessed at baseline, 30 days and 90 days, respectively.

Results:

Highly significant values were achieved for plaque index (P=0.00), and significant values were obtained for gingival index (P=0.044). Reduction in bleeding on probing was found to be highly significant. Probing depth and clinical attachment level showed no inter group variation.

Conclusion:

The results of this double-blind trial indicate that the combined effect of locally delivered ketoprofen with SRP was more effective in controlling periodontal disease than SRP alone.

Abstract P3-14-06: Pharmacokinetic (PK) Interaction Potential of Trastuzumab-DM1 (T-DM1) and Pertuzumab (P) in Pts with HER2-Positive, Locally Advanced or MBC: Results from a Phase 1b/2 Study

Introduction

T-DM1 is an antibody-drug conjugate (ADC) composed of the cytotoxic DM1 conjugated to trastuzumab and retaining its antitumor properties. P is a HER2-directed monoclonal antibody that inhibits HER2 dimerization and subsequent signaling. The combination of T-DM1 and P has demonstrated synergistic antitumor activity in HER2-positive xenograft models. T-DM1 and P are expected to undergo proteolytic degradation with no significant involvement of cytochrome P450 isoenzymes. In contrast, DM1 is metabolized mainly by CYP3A4 and to a limited extent by CYP3A5. Therefore, a key component in evaluating this combination clinically is determining whether a PK-based drug interaction potential exists when these drugs are administered together. Assessment of PK-based therapeutic protein-ADC interaction potential is novel, as antibodies have typically been combined with chemotherapy in clinical studies. Methods

This 3+3 dose escalation, open-label, phase 1b/2 study evaluated the safety, tolerability, PK, and efficacy of T-DM1 (3.0 mg/kg q3w or 3.6 mg/kg q3w [established phase 2 dose]) in combination with P (840 mg loading dose; 420 mg q3w thereafter) in pts with HER2-positive locally advanced or MBC. Because of the half-life of both agents, staggered dosing was not a practical approach to assess the PK interaction. Thus, both drugs were administered sequentially on Day 1 of each cycle. All pts receiving study treatment were evaluated for serum concentrations of T-DM1, total trastuzumab (conjugated and unconjugated to DM1), and plasma concentrations of DM1, at pre-specified time points. To avoid the interference of P with the quantification of total trastuzumab, a new assay that allows capturing trastuzumab in the presence of P was developed and validated. PK of T-DM1 and related analytes were compared with historical single agent data by population and/or noncompartmental analyses. Whether combination with P was a significant covariate of T-DM1 clearance and central volume of distribution (V1) was tested. The confidence intervals (CIs) of the ratios of clearance and V1 of combination to monotherapy were estimated. A CI containing 1 is indicative of comparable parameters. Results

PK data were available for 63 pts. Combination with P was not a significant covariate of T-DM1 clearance and V1 (P&gt;0.05 by the log likelihood ratio test). The combination to monotherapy ratios for clearance and V1 had a 95% CI of [0.90-1.04] and [0.95-1.06], respectively, indicating comparable clearance and V1 of combination and monotherapy. The average post-hoc Bayesian estimates of T-DM1 clearance and V1 in the presence of P were 0.69±0.14 L/day and 3.3±0.41 L, which were comparable with historical measures of 0.73±0.19 L/day and 3.4±0.57 L with monotherapy. The average maximal concentration of total trastuzumab in cycle 1 was 101±29 μg/ml in the 3.0 mg/kg TDM1 dose (n=3) and 98±32 μg/ml for the 3.6 mg/kg dose (n=60). The maximum DM1 level was &lt;17 ng/mL at both T-DM1 doses. The PK of total trastuzumab and DM1 were also comparable with monotherapy (data not shown).

Conclusions

This assessment suggests that P does not alter the PK of T-DM1 when these drugs are administered together.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-14-06.

Random safety audits in the neonatal unit

BACKGROUND

Random safety audits have been shown to be effective in improving standards of practice in high-risk industries. They are process audits rapidly performed during real-time clinical activity, with immediate feedback, allowing for immediate change of practice.

AIM

Based on a concept described by the Vermont-Oxford Network, we aimed to introduce random safety audits to our unit to improve infection control and routine neonatal care.

METHOD

We designed simple data collection tables to audit 11 infection control and four routine care standards. Audits were undertaken during the weekly grand round. Immediate feedback was given.

RESULTS

In 6 months we completed three cycles of 15 audits each. Complete results were available for 14 audits. The compliance with the infection control standards improved from a median of 70% (range 20%-100%) to 95% (range 66%-100%). The results of the routine care standards were more variable.

CONCLUSION

We have shown that this innovative method of random safety audits is effective in quickly improving practice. We believe this to be due to the instant feedback, continued emphasis on infection control and good clinical practice, and improved teamwork.

A phase I study of trastuzumab-MCC-DM1 (T-DM1), a first-in-class HER2 antibody-drug conjugate (ADC), in patients (pts) with HER2+ metastatic breast cancer (BC)

1042

Background: ADCs utilize tumor-specific and/or over-expressed surface antigens that undergo internalization to deliver highly potent anti-tumor agents via linkage to antigen-specific monoclonal antibodies (MoAbs). T-DM1 contains the humanized anti-HER2 MoAb trastuzumab (T) previously demonstrated to prolong survival in HER2+ BC to which a highly potent antimicrotubule drug (DM1) derived from maytansine has been chemically linked. Maytansine has been studied as a free drug with responses noted in breast and lung cancer pts; principal adverse events (AEs) were nausea, vomiting, diarrhea, and neuropathy. The MCC linker employed in T-DM1 provides a stable bond between T and DM1 that is designed to prolong exposure and reduce the toxicity of T-DM1 while maintaining activity; T-DM1 is the first ADC with an MCC linker in clinical trials. T-DM1 has activity in T-resistant HER2+ BC xenografts; its principal preclinical toxicities were reversible transaminase elevations, reversible decreases in platelets, and neuropathy. Methods: This ongoing first-in-human phase I study is evaluating the safety and pharmacokinetics (PK) of T-DM1 given IV q3 weeks to pts with HER2+ metastatic BC who have progressed on a T-containing regimen. Results: Seven pts (median age 58 (range 47–70); all PS 0–1; median number prior chemo regimens 6 (range 5–11)) have received 24 doses of T-DM1 at 5 dose levels (0.3–4.8 mg/kg). Related grade (gr) 1–2 AEs include elevations in hepatic transaminases (2 pts), fatigue (2 pts), anemia (1 pt), and thrombocytopenia (TCP, 1 pt). Related gr 3–4 AEs have been limited to rapidly reversible gr 4 TCP at 4.8 mg/kg (1 pt). There has been no cardiac toxicity. Consistent with preclinical modeling, dose dependent decrease in clearance was observed for T-DM1 across dose levels. One pt at 2.4 mg/kg has maintained an ongoing partial response for 6 cycles. Conclusions: At these initial doses, gr =2 AEs related to T-DM1 have been infrequent and manageable; gr 4 (dose-limiting) rapidly reversible TCP was seen at 4.8 mg/kg. T-DM1 PK is consistent with q3-week dosing. Objective tumor response has been observed. Enrollment is ongoing to determine the maximum tolerated dose of q3-week T-DM1.

No significant financial relationships to disclose.

Density-dependent growth and metamorphosis in the larval bronze frog Rana temporalis is influenced by genetic relatedness of the cohort

Effects of density and kinship on growth and metamorphosis in tadpoles of Rana temporalis were studied in a 2 4 factorial experiment. Fifteen egg masses were collected from streams in the Western Ghat region of south India. The tadpoles were raised as siblings or in groups of non-siblings at increasing density levels, viz. 15, 30, 60 and 120/5 l water. With an increase in density level from 15 to 120 tadpoles/5 l water, duration of the larval stage increased and fewer individuals metamorphosed irrespective of whether they belonged to sibling or non-sibling groups by day 100 when the experiments were terminated. The size of individuals at metamorphosis declined significantly with increase in the density of rearing. However, at higher densities (60 and 120 tadpoles/5 l water) sibling group tadpoles performed better compared to mixed groups and took significantly less time to metamorphose. Also, more individuals of sibling groups metamorphosed compared to non-sibling groups at a given density. Mixed rearing retarded growth rates, prolonged larval duration resulting in a wider spectrum of size classes, and lowered the number of individuals recruited to terrestrial life. The study shows that interference competition occurred more strongly in cohorts of mixed relatedness than in sibling groups.

The ontogeny of kin recognition in tadpoles of the toad Bufo melanostictus (Anura; bufonidae)

The ontogeny of kin recognition and influence of social environment on the development of kin recognition behaviour was experimentally investigated in tadpoles of Bufo melanostictus that lived in aggregations and showed low larval dispersion. Embryos and tadpoles of the toad were reared as (i) kin only, (ii) with kin and non-kin (separated by a mesh screen), and (iii) in isolation. They were tested for the ability to discriminate between (i) familiar siblings and unfamiliar non-siblings, (ii) familiar siblings and familiar non-siblings and, (iii) unfamiliar siblings and unfamiliar non-siblings. All tadpoles were fed on boiled spinach before conducting trials. Preference of test tadpoles to associate near the end compartments whether empty or containing members of specific stimulus groups was assessed using a rectangular choice tank. When tested in tanks with empty end compartments, the test tadpoles showed random distribution and thus no bias for the apparatus or the procedure. In the presence of kin/non-kin in the end compartments a significantly greater number of test tadpoles spent the majority of the time near familiar or unfamiliar kin rather than near familiar or unfamiliar non-kin. Kin discrimination ability persisted throughout larval development. Familiarity with siblings is not required for discriminating kin from non-kin, and kin discrimination ability is not modified following exposure to non-kin. Also, involvement of dietary cues is unlikely to be the prime mechanism of kin recognition in B. melanostictus unlike in some other anurans.

Interrelationship between food availability, fat body, and ovarian cycles in the frog, Rana tigrina, with a discussion on the role of fat body in anuran reproduction

Long-term experiments were conducted to study the progression of vitellogenic cycles in Rana tigrina (an annual breeder) having different foraging backgrounds and held under conditions of weekly or daily food supply and in presence or absence of abdominal fat bodies. They were autopsied in June to assess fecundity. In nature an adult R. tigrina produces on an average 4,000 eggs/100 g body mass (b.m.) And spawns in June-July following monsoon rains. Weekly feeding from July to next breeding season, June resulted in a significant decrease in both fecundity (1700 eggs/100 g body b.m.) And mean size of eggs, compared to well-fed or wild-caught frogs. The abdominal fat bodies were barely seen in frogs fed weekly throughout, whereas in frogs fed weekly from July-December but daily from January onwards, the fat bodies became noticeable (1% of b.m.) And number and mean size of eggs increased significantly over those fed weekly throughout. Frogs captured in January possessed enlarged fat bodies (5% of b.m.), depicting a good foraging history. Maintenance of these frogs on a weekly feeding regimen led to an exhaustion of fat stores. They produced less number of eggs (2, 000/100 g b.m.) As compared to wild frogs but of normal size, whereas daily feeding slowed down a depletion of fat body mass and also significantly increased fecundity (3,000/100 g b.m.) Over the weekly fed individuals. Sham operation or fat body ablation in October or February had no significant effect on total fecundity per se (3,000-3,500 eggs/100 g b.m.) Compared to that of wild-caught frogs. However, eggs were significantly smaller due to fat body ablation despite daily feeding. The study shows that food abundance/fat bodies influence egg size and number in R. tigrina and that a direct or indirect functional relationship exists between fat body and ovarian cycles that are characteristically inverse to each other. J. Exp. Zool. 286:487-493, 2000.