Lapatinib Plasma and Tumor Concentrations and Effects on HER Receptor Phosphorylation in Tumor

PURPOSE

The paradigm shift in cancer treatment from cytotoxic drugs to tumor targeted therapies poses new challenges, including optimization of dose and schedule based on a biologically effective dose, rather than the historical maximum tolerated dose. Optimal dosing is currently determined using concentrations of tyrosine kinase inhibitors in plasma as a surrogate for tumor concentrations. To examine this plasma-tumor relationship, we explored the association between lapatinib levels in tumor and plasma in mice and humans, and those effects on phosphorylation of human epidermal growth factor receptors (HER) in human tumors.

EXPERIMENTAL DESIGN

Mice bearing BT474 HER2+ human breast cancer xenografts were dosed once or twice daily (BID) with lapatinib. Drug concentrations were measured in blood, tumor, liver, and kidney. In a randomized phase I clinical trial, 28 treatment-naïve female patients with early stage HER2+ breast cancer received lapatinib 1000 or 1500 mg once daily (QD) or 500 mg BID before evaluating steady-state lapatinib levels in plasma and tumor.

RESULTS

In mice, lapatinib levels were 4-fold higher in tumor than blood with a 4-fold longer half-life. Tumor concentrations exceeded the in vitro IC90 (~ 900 nM or 500 ng/mL) for inhibition of HER2 phosphorylation throughout the 12-hour dosing interval. In patients, tumor levels were 6- and 10-fold higher with QD and BID dosing, respectively, compared to plasma trough levels. The relationship between tumor and plasma concentration was complex, indicating multiple determinants. HER receptor phosphorylation varied depending upon lapatinib tumor concentrations, suggestive of changes in the repertoire of HER homo- and heterodimers.

CONCLUSION

Plasma lapatinib concentrations underestimated tumor drug levels, suggesting that optimal dosing should be focused on the site of action to avoid to inappropriate dose escalation. Larger clinical trials are required to determine optimal dose and schedule to achieve tumor concentrations that maximally inhibit HER receptors.

TRIAL REGISTRATION

CLINICAL TRIAL REGISTRATION

NCT00359190.

Abstract P4-03-01: Analysis of the impact of intraoperative margin assessment with adjunctive use of MARGINPROBE® vs. standard of care on margin status with different definitions of positive margin depth, results from a randomized prospective multi center study

Background: The current practice of breast conserving surgery (BCS) involves intraoperative margin assessment according to the surgeon's gross assessment and judgment. This intraoperative assessment has been associated with a 20% to 40% reoperation rate to assure negative margins. MarginProbe (Dune Medical Devices, MA, USA) was developed to provide real-time assessment of lumpectomy specimens to evaluate for the presence of disease at the surgical margins. A 21-center international pivotal study was conducted to determine if adjunctive use of MarginProbe can enable surgeons to identify positive margins intraoperatively, resulting in fewer patients who are candidates for re-excision procedures. Results for a 1mm definition of positive margins have been reported previously. We sought to understand the benefit of device use at alternative thresholds.

Methods: 664 women with non-palpable lesions undergoing lumpectomy for DCIS and invasive cancer were enrolled and 596 randomized (1:1) in the operating room following standard of care (SOC) lumpectomy. In the device arm, MARGINPROBE was used to assess all surfaces of the lumpectomy specimen and positive readings required additional resections. The device was not used on additional resections. All specimens were examined to verify excision of the target lesion intraoperatively. Pathologists were blinded to study arm. Additional surgeries to re-excise involved margins were performed per each individual site criteria. Patients were followed for 2 months following surgery; additional procedures were documented. Distance from tumor to each margin face was recorded for each patient.

Results: Following lumpectomy, the number of patients having positive margins due to failed intraoperative assessment was significantly reduced in the device arm at each potential definition of positive margins.

Patients with positive margins after 1st surgeryDepthDevice (%) N = 298Control (%) N = 298p-value0mm6.413.40.00571mm15.438.3<0.00012mm22.549.7<0.00013mm30.957.0<0.00014mm36.661.7<0.00015mm39.966.4<0.0001*excludes positive margins on shavings, as device was only used on the main specimen

Conclusions: It has been shown previously that adjunctive use of MARGINPROBE significantly reduced the number of candidates for re-excision at a 1mm definition of positive margins. Based on this analysis, surgeons can expect a substantial reduction in the number of patients with positive margins at definitions from tumor on ink to 5mm.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-03-01.

The POTENT II randomised trial: efficacy and safety of an orodispersible vardenafil formulation for the treatment of erectile dysfunction

AIMS

The aim of this study was to investigate the efficacy and safety of 10 mg vardenafil orodispersible tablet (ODT) vs. placebo in a general population of men with erectile dysfunction (ED).

METHODS

This was a double-blind, multicentre, randomised, parallel-group, placebo-controlled study conducted at 35 centres in Australia, Canada, Mexico and the United States. Subjects aged > or =18 years, with ED for at least 6 months, were randomised to receive 12 weeks of on-demand treatment with either 10 mg vardenafil ODT or placebo. Each treatment group was stratified such that approximately half of the subjects were aged > or = 65 years. Primary efficacy variables were the erectile function domain of the International Index of Erectile Function (IIEF-EF) and Sexual Encounter Profile questions 2 (SEP2) and 3 (SEP3). Secondary variables included SEP diary questions 1, 4, 5 and 6, the patient version of the Treatment Satisfaction Scale (TSS) and the Global Assessment Question (GAQ).

RESULTS

Of the 473 men enrolled in the study (51.4% aged > or =65 years), 331 were included in the intent-to-treat population (vardenafil ODT, n = 169; placebo, n = 162). Vardenafil ODT therapy was statistically significantly superior to placebo for all primary (i.e. IIEF-EF, SEP2, SEP3) and secondary efficacy variables (p < 0.0001). Treatment-emergent adverse events were mostly mild to moderate in severity, and comparable in both incidence and type with those of the film-coated tablet formulation.

CONCLUSIONS

Treatment with 10 mg vardenafil ODT, taken on demand, significantly improved erectile function and was effective and well tolerated in a broad population of men with ED.

Degarelix: A gonadotropin-releasing hormone receptor (GnRH) blocker, tested in two one-year multicenter, randomized, dose-finding studies in prostate cancer patients

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Background: The GnRH receptor blocker degarelix has immediate onset of action in suppressing gonadotropins (LH and FSH), testosterone (T) and prostate specific antigen (PSA) and does not cause T surge. Its long-term efficacy and safety in different maintenance dosing regimens were evaluated in prostate cancer (CaP) patients. Methods: Degarelix was investigated in two multicenter, one-year studies in North America and Europe/South Africa. Degarelix initiation doses of 200 and 240 mg administered subcutaneously, followed by three maintenance doses (80, 120 and 160 mg). Therapeutic effect was assessed by measuring T and PSA levels. 314 patients (age 47–93, median 73 years) with histologically confirmed CaP, PSA ≥2 ng/mL received degarelix subcutaneously every 28 days. Median baseline T was 4.1 ng/mL and PSA was 20 ng/mL. 19% of patients had metastatic, 24% had locally advanced and 30% had localized CaP. 27% were M0/MX and not T-staged. Tumour grade was well differentiated (Gleason 2–4) in 13%, moderately differentiated (5–6) in 38%, and poorly differentiated (7–10) in 49% of the patients. Results: T levels ≤0.5 ng/mL were achieved in 92% of patients at Day 3 and 95% of patients at Day 28 among those treated with 240 mg (40 mg/mL) degarelix. From Day 28 until Day 364, 100% of patients receiving maintenance doses of 160 mg had T levels consistently ≤0.5 ng/mL. No evidence of T surge was detected. PSA decreased by 90% at 8 weeks after starting therapy, 94% at 12 weeks and 96% at 24 weeks. Twelve patients (6%) withdrew from the study due to adverse events, largely related to androgen deprivation. There were no cases of systemic allergic reactions. Conclusion: Degarelix treatment for one year resulted in fast, profound and sustained suppression of T (≤0.5 ng/mL) and fast, profound and sustained reduction of PSA levels. Degarelix was well tolerated without evidence of T surge or systemic allergic reactions. [Table: see text]

[Table: see text]

Efficacy, tolerability and safety of darifenacin, an M(3) selective receptor antagonist: an investigation of warning time in patients with OAB

This double-blind, randomised placebo-controlled, multicentre study evaluated the efficacy, tolerability and safety of 12 weeks' treatment with controlled release darifenacin 15 mg once daily (qd), in 445 patients with overactive bladder (OAB). The primary endpoint was warning time (time from first sensation of urgency to voiding), and secondary endpoints included urge incontinence episodes and volume voided. Darifenacin treatment resulted in numerical increases in warning time, but these were not significant compared with placebo -- highlighting difficulties in assessing this parameter. Significant improvements were seen with darifenacin vs. placebo in urge incontinence episodes/week, volume voided and quality of life (QoL). Darifenacin was associated with increases in urgency-free time (UFT; time between any void to the next urgency event) vs. placebo. Treatment was well tolerated; the most commonly reported adverse events were the typical antimuscarinic effects of dry mouth and constipation, both infrequently leading to discontinuation. This study demonstrated the difficulty in measuring warning time, due in part to its subjective nature; the authors believe further investigation is warranted to allow urgency to be better defined. Further investigation of UFT is required to determine its role in evaluating urgency. The study confirmed that darifenacin 15 mg qd is an effective and well-tolerated treatment for OAB, which improves QoL.

The gonadotropin-releasing hormone antagonist abarelix depot versus luteinizing hormone releasing hormone agonists leuprolide or goserelin: initial results of endocrinological and biochemical efficacies in patients with prostate cancer

PURPOSE

We contrasted the endocrinological and biochemical efficacies of abarelix depot, a pure gonadotropin-releasing hormone antagonist, with a prospective concurrent control cohort receiving luteinizing hormone releasing hormone (LH-RH) agonists with or without antiandrogen for treatment of patients with prostate cancer receiving initial hormonal therapy.

MATERIALS AND METHODS

In this phase 2 open label study 242 patients with prostate cancer requiring initial hormonal treatment received abarelix depot (209) or LH-RH agonists (33) with or without antiandrogen. A total of 100 mg. abarelix depot was delivered intramuscularly every 28 days with an additional injection on day 15. LH-RH agonists with or without antiandrogen were administered according to the depot formulation used. Endocrine efficacy was measured by the absence of testosterone surge and rapidity of castration onset. The rate of prostate specific antigen decrease was assessed.

RESULTS

No patient treated with abarelix depot had testosterone surge during week 1 compared with 82% of those treated with LH-RH agonists. The concomitant administration of antiandrogen had no effect. During the first week of drug administration, in 75% of patients treated with abarelix depot and in 0% of those treated with LH-RH agonist medical castration was achieved. Prostate specific antigen decrease was faster, with no flare or surge in patients treated with abarelix depot. Abarelix depot was well tolerated.

CONCLUSIONS

Abarelix depot represents a new class of hormonal therapy, gonadotropin releasing hormone antagonists, that has rapid medical castration and avoids the testosterone surge characteristic of LH-RH agonists.

Serum prostate-specific antigen and prostate volume predict long-term changes in symptoms and flow rate: results of a four-year, randomized trial comparing finasteride versus placebo. PLESS Study Group

OBJECTIVES

To determine whether baseline prostate-specific antigen (PSA), in addition to prostate volume, is associated with long-term changes in symptoms and urinary flow rate.

METHODS

Three thousand forty men with benign prostatic hyperplasia enrolled in the PLESS trial were randomly assigned to finasteride 5 mg or placebo for 4 years. Symptoms and flow rate were assessed every 4 months, and data were analyzed by dividing the patients into three groups by baseline PSA tertiles (0 to 1.3, 1.4 to 3.2, and 3.3 ng/mL or greater) and baseline prostate volume tertiles (14 to 41, 42 to 57, and 58 to 1 50 mL).

RESULTS

After the initial placebo effect, a slow deterioration in symptoms over time was observed in the placebo-treated men with a baseline PSA 1.4 ng/mL or greater. However, placebo-treated men in the lowest PSA tertile (less than 1.4 ng/mL) had sustained symptomatic improvement that was not seen in placebo-treated men in the higher tertiles (P<0.001). In all finasteride-treated groups, there was initial improvement followed by maintenance or continued symptom improvement over time (approximately 3 to 3.5 points by the end of 4 years). The differences in symptom score improvement between placebo and finasteride were marginal for men with baseline PSA levels less than 1.4 ng/mL (P = 0.128) but were highly significant for men with PSA levels 1.4 ng/mL or greater (P<0.001). Urinary flow rate results were similar to those observed for symptoms. Analysis of symptom and flow rate data by prostate volume tertiles in a 10% subset of men yielded similar results, namely a deterioration of symptoms and flow rate in the two higher tertiles treated with placebo (greater than 41 mL) and a sustained improvement in all three groups of finasteride-treated patients.

CONCLUSIONS

Baseline PSA and prostate volume are good predictors of long-term symptomatic and flow rate changes. Baseline PSA levels of 1.4 ng/mL or greater and enlarged prostate glands predict the best long-term response to finasteride compared with placebo.

Group psychoeducation of relatives of schizophrenic patients: two-year experiences

In order to assess the feasibility and acceptability of group psychosocial education for the relatives of schizophrenics in the community, a 2-year project was carried out in two cities: Jinan and Shanghai, China. The completed sample included 682 cases in the experimental group and 366 cases in the control group. The experimental group received group psychotherapy including 14 lectures and five group discussions with conventional services, and the control group had conventional services only. The annual relapse rate in the experimental group was much lower than that in the control group (17.6 and 23.2%, P < 0.01) and the rate of regular work in the experimental group was higher than that in the control group (37.5 and 30.0%, P < 0.05). At the end of the second year, the relatives in the experimental group had less care burden, better mental and physical health status and more knowledge of caring for schizophrenics than those in the control group. This approach was well accepted by both mental health workers and relatives of schizophrenics and the rate of drop-out was 18.4% only during the 2-year period.

Recent developments in the care, treatment, and rehabilitation of the chronic mentally ill in Greece

The chronic mentally ill in Greece are primarily cared for in large public mental hospitals or by their families because of the absence of community-based alternatives and the centralization of existing services in Athens and Thessaloniki. However, in the last decade new legislation to improve the lives of the chronically ill has been passed, additional day care facilities have been opened, and the development of decentralized mental health services has been scheduled by the National Health System. A case report illustrates the care provided at Greece's first community mental health center, established in 1979 in Athens.