Abstract P6-04-12: Novel selective estrogen receptors degraders regress tumors in pre-clinical models of endocrine-resistant breast cancer

80% of all breast cancers express the estrogen receptor alpha (ERα) and thus are treated with anti-hormonal therapies that directly block ER function (e.g. Tamoxifen) or hormone synthesis (Aromatase Inhibitors). While these therapies are initially effective, acquired resistance invariably emerges. Importantly, the majority of these tumors continue to depend on ERα for growth and survival. The emerging evidence that ERα can signal in both a ligand-dependent and ligand-independent manner supports the development of agents that are not only competitive ERα antagonists but also reduce steady state levels of the receptor and thus limit both modes of signaling.

We have identified novel, non-steroidal ERα antagonists that induce degradation of ERα in breast cancer cell lines at picomolar concentrations resulting in significant reduction in steady state ERα protein levels. Using peptide-based conformational profiling, we show that these Selective Estrogen Receptor Degraders (SERDs) induce estrogen receptor conformations that are distinct from both fulvestrant and tamoxifen indicating a unique mechanism of action. This unique biological profile coupled with good oral pharmacokinetics produces tumor regressions in both tamoxifen-sensitive and -resistant models of breast cancer in vivo. Recent pre-clinical and clinical data indicate that PI3K pathway signaling can contribute to the endocrine resistant state. In a preclinical model of tamoxifen resistant breast cancer in which SERD monotherapy only produces tumor growth inhibition, SERD therapy in combination with torc1/2 inhibition results in frank tumor regressions. These orally bioavailable SERDs hold promise as a next generation therapy for the treatment of ER+ breast cancer as monotherapy, as well as in combination with agents that target other pathways involved in both intrinsic and acquired endocrine resistance.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-12.

The pharmacology of bimatoprost (Lumigan)

Bimatoprost (Lumigan) is a pharmacologically unique and highly efficacious ocular hypotensive agent. It appears to mimic the activity of a newly discovered family of fatty acid amides, termed prostamides. One biosynthetic route to the prostamides involves anandamide as the precursor. Bimatoprost pharmacology has been extensively characterized by binding and functional studies at more than 100 drug targets, which comprise a diverse variety of receptors, ion channels, and transporters. Bimatoprost exhibited no meaningful activity at receptors known to include antiglaucoma drug targets as follows: adenosine (A(1-3)), adrenergic (alpha(1), alpha(2), beta(1), beta(2)), cannabinoid (CB(1), CB(2)), dopamine (D(1-5)), muscarinic (M(1-5)), prostanoid (DP, EP(1-4), FP, IP, TP), and serotonin (5HT(1-7)). Bimatoprost does, however, exhibit potent inherent pharmacological activity in the feline iris sphincter preparation, which is prostamide-sensitive. Bimatoprost also resembles the prostamides in that it is a potent and highly efficacious ocular hypotensive agent. A single dose of bimatoprost markedly reduces intraocular pressure in dogs and laser-induced ocular hypertensive monkeys. Decreases in intraocular pressure are well maintained for at least 24 hr post-dose. Human studies have demonstrated that systemic exposure to bimatoprost is low and that accumulation does not occur. The sclera is the preferred route of accession to the eye. The high scleral permeability coefficient Papp is a likely contributing factor to the rapid onset and long-acting ocular hypotensive profile of bimatoprost.

Managing the unmanageable: risk assessment and risk management in contemporary professional practice

AIM

This study sets out to investigate the theories and practices of risk assessment and management in the context of contemporary mental health practice.

BACKGROUND

Although risk assessment and management policies are well established for those working in the field of community mental health care, there are noticeable anomalies and regional variations, in the criteria, procedures and decision-making strategies used.

METHODS

Focus group taped interviews were conducted with over 100 mental health professionals in one NHS Trust. These were compared with an extensive literature review on the topic.

FINDINGS

The main theme to emerge was lack of resources, which included time and staff in the context of a changing and increasing workload. Another important theme was the lack of access to centralized and accurate information about mental health service provision.

CONCLUSION

It is essential that professionals, clients, their families and the public feel confident in professional judgements and practices to avoid a 'back to the asylum' lobby, for the care and treatment of seriously mentally ill individuals.

Penetration of natural prostaglandins and their ester prodrugs and analogs across human ocular tissues in vitro

The objective of this study was to assess the corneal and scleral permeabilities of natural prostaglandins as well as their prodrugs and analogs through human cornea and sclera in vitro. The "apparent permeability coefficients" (Papp) of natural prostaglandins (PGF2alpha, PGD2 and PGE2), ester prodrugs of PGF2alpha (1-isopropyl PGF2alpha, 11-pivaloyl PGF2alpha and 11,15-dipivaloyl PGF2alpha) and four analogs (16-m-chlorophenoxy tetranor PGF2alpha, 17-phenyl trinor PGF2alpha, 17-phenyl trinor PGE2 and AH 13205) were measured using modified Ussing perfusion chambers and quantitative high performance liquid chromatography. Our results indicate that the corneal penetration of natural prostaglandins (PGs) is poor (the Papp values ranged from 1.65 x 10(-6) to 2.38 x 10(-6) cm/sec), while the PGF2alpha prodrugs showed higher corneal penetration than PGF2alpha. The 11-pivaloyl ester of PGF2alpha penetrated the cornea faster than both 1-isopropyl ester and the lipophilic 11,15-dipivaloyl ester. The PG analogs also showed poor corneal penetration (Papp values ranged from 0.696 x 10(-6) to 1.49 x 10(-6) cm/sec) except for AH 13205. All compounds tested showed good scleral penetration (Papp values ranged from 6.90 x 10(-6) to 17.1 x 10(-6) cm/sec) except PGF2alpha 11,15-dipivaloyl (Papp = 1.22 x 10(-6) cm/sec). The penetration profiles correlated well with tissue uptake ratios (ratio of final tissue concentration to initial dose) for all compounds except 11,15-dipivalate PGF2alpha. All ester prodrugs (but not the PGs and analogs) underwent corneal first-pass metabolism. The study results demonstrate that transcleral absorption may play a significant role in the ocular absorption of these compounds.

The use of precision-cut rat lung slices for studying PGF(2α) metabolism

The suitability of a dynamic lung slice culture system as an in vitro model for studying pulmonary metabolism of PGF(2α) was assessed. [(3)H]Prostaglandin F(2α) ([(3)H]PGF(2α)), a twenty carbon fatty acid that contains a five-carbon ring and is known to be metabolized by lung in vivo, was incubated with precision-cut rat lung slices in 1.7 ml of Waymouth's buffer fortified with 10% fetal calf serum. At 0, 2, 4 and 8 h after addition of [(3)H]PGF(2α) (1.82 ng/μCi), incubation was stopped and the contents of each vial were analyzed for [(3)H]PGF(2α) and its metabolites using reversed-phase HPLC with radiochemical detection. PGF(2α) was metabolized to 15-keto PGF(2α), 13,14-dihydro-15-keto PGF(2α), and two unknown minor polar metabolites. These results indicate that PGF(2α) was metabolized in lung slices pathways similar to those seen in vivo. Slice viability was assessed by protein synthesis and light microscopic examination of lung slices through 24 h of incubation. Protein synthesis was maintained and no tissue necrosis was observed over the entire 24 h incubation, indicating that the lung slices were viable for at least 24 h. These results indicate that the dynamic lung slice culture system is an appropriate in vitro model for studying the pulmonary metabolism of PGF(2α).

Metabolic deesterification of tazarotene in human blood and rat and human liver microsomes

Tazarotene is a novel acetylenic retinoid for the treatment of psoriasis and acne. We examined (1) the hydrolysis of tazarotene in blood from Japanese-American and Caucasian subjects, (2) the esterases responsible for this hydrolysis in human blood, and (3) tazarotene hydrolysis in rat and human liver microsomes. Tazarotene hydrolysis and enzyme inhibition were assessed by monitoring the disappearance of tazarotene and the appearance of its primary metabolite tazarotenic acid by HPLC. In blood, tazarotene was converted mainly to tazarotenic acid via first-order kinetics, and there was no statistically significant difference in the hydrolytic (metabolic) rate of tazarotene in uninhibited Japanese-American and Caucasian blood. Physostigmine (a cholinesterase inhibitor), bis(p-nitrophenyl) phosphate (a carboxylesterase inhibitor), and EDTA (an aromatic esterase inhibitor) did not significantly affect tazarotene hydrolysis in blood. Paraoxon, an inhibitor of all serine esterases including cholinesterase and carboxylesterase, decreased the hydrolysis of tazarotene to tazarotenic acid by 95% in both blood and liver microsomes. In conclusion, blood and liver esterases play a significant role in the hydrolysis of tazarotene to tazarotenic acid, and paraoxon-inhibitable forms of esterases are involved in this hydrolysis in humans.

Cervical ripening and induction of delivery by local administration of prostaglandin E2 gel or vaginal tablets is equally effective

BACKGROUND

Prostaglandin E2 for local application has been widely used for preinduction cervical ripening in cases presenting with an unfavorable cervical state. The optimal way of administering prostaglandin E2, however, remains unclear. The aim of this study was to compare the effect of multiple application of 0.5 mg Minprostin intracervical Gel to the effect of 3 mg Minprostin vaginal tablets in priming the uterine cervix and inducing labor in an open, prospective, randomised study.

METHODS

PGE2 was applied up to three times a day for two days until ripening was obtained or labor induced. In case no progress took place amniotomy was performed and i.v. oxytocin stimulation one hour later if necessary. A total of 208 pregnant women, consecutively admitted for induction of delivery, with Bishop Scores 0-5, were included.

RESULTS

Minprostin gel (group I) and Minprostin tablets (group II) were equally effective in ripening the cervix. Delivery within 48 hours was achieved in 59% and 63% respectively. The mean number of applications was 2.6 (s.d. 1.6) and 2.7 (s.d. 1.3) respectively. In case more than four doses were required no further effect was seen on delivery rates. Rates of cesarean section (performed in 15% and 18% respectively), labor induction (3%/1%), drop outs (14%/12%) and failed inductions (10%/5%) were comparable. Patients in group I had a significantly lower demand for analgesia. A significantly shorter induction-delivery interval in group II was seen in patients with preinduction Bishop scores 3-5 compared to patients with Bishop scores 0-2. Side effects were few. Both procedures appear safe.

CONCLUSIONS

Cervical ripening and induction of delivery by local administration of prostaglandin E2 gel or vaginal tablets in cases presenting with an unfavorable cervical state is equally effective.

Lupus anticoagulant and anticardiolipin antibodies in an obstetric population

Lupus anticoagulant (LA) and anticardiolipin antibodies (ACA) have been reported to be associated with fetal loss. OBJECTIVE. Our aim was to estimate the incidence of LA and to examine the correlation between LA and ACA in pregnant women. To investigate the clinical significance of LA and ACA in an obstetric population. STUDY DESIGN. A prospective, cross sectional study of 2856 consecutive women admitted to a department of obstetrics and gynecology for delivery or due to pregnancy complications during an 11 month period. METHODS. Activated partial thromboplastin time (APTT) was determined in all patients. LA and ACA were determined if APTT > or = 35 sec. For reference ACA was determined in a group of randomly selected patients with APTT < 35 sec. The results were analyzed in relation to the obstetrical records. RESULTS. Overall incidence of APTT > or = 35 sec.: 7.0%, significantly more frequent in patients with early spontaneous abortion (18.6%) and intrauterine growth retardation (17.5%). Incidence of LA 0.07%. The patients had undetectable ACA and no clinical condition related to LA. Incidence of ACA class IgM (IgM-ACA) in patients with APTT > or = 35: 20.4%, significantly higher than in the reference group (9.6%). Uncomplicated pregnancy in 84% of patients with IgM-ACA. No cases of ACA class IgG (IgG-ACA) in patients with APTT > or = 35 but two cases in the reference group (one normal pregnancy, one spontaneous abortion). CONCLUSION. LA is a rare manifestation with uncertain significance in otherwise healthy pregnant women. IgM-ACA in low titer occurs relatively frequently during normal pregnancy.

[Induction of labor. Prostaglandin E2 vaginal tablets compared with intravenous oxytocin for induction of labor in premature rupture of the membranes and immature cervix]

In a material of 88 patients with premature rupture of the membranes and unripe cervix, a comparative investigation was undertaken to compare the effects of prostaglandin E2 (PGE2) vaginal tablets and intravenous oxytocin on induction of labour. The patients were subdivided at random into two groups: 42 patients treatment with PGE2 and 46 treatment with intravenous oxytocin. The results did not reveal any significant differences in the numbers of successful inductions regardless of the Bishop score at the commencement of stimulation but the duration of induction was found to be briefer in the oxytocin group. No significant differences were observed in the numbers of instrumental interventions in the two groups nor in the frequencies of side effects and in the employment of analgesics. Treatment with PGE2 vaginal tablets is considered to be more acceptable by the patients and easier for the staff to use. The tablets were just as safe and reliable in use as intravenous oxytocin for induction of labour in cases of premature rupture of the membranes and Bishop scores less than 6, but the duration of induction was significantly longer.

Benign cystic monodermal teratoma of neurogenic type

We report a case of a benign monodermal cystic teratoma in a 19-year-old woman. The tumor was purely neurogenic, containing glial tissue, ganglionic cells, melanotic cells, and choroid plexus. The cyst tumour is the first of its kind described in the literature.

Norfenefrine in the treatment of female urinary stress incontinence assessed by one-hour pad weighing test

Thirty-three women with urinary stress incontinence were treated with the alpha-adrenoceptor-stimulating agent, norfenefrine (Nevadral Retard). Treatment was administered during 3-24 weeks at a daily dosage of 90 mg. Judged by a 1-hour pad weighing test, a significant effect could be demonstrated. With the exception of 1 case of allergic reaction and 1 case of recurrent vomiting, a simultaneously performed tolerability test revealed only minor side effects.

Does medical therapy cure female stress incontinence?

Forty-four consecutive female patients, who were scheduled for operation for genuine stress incontinence but instead treated pharmacologically with an alpha-agonist or placebo for 3-4.5 months, were evaluated after a median observation period of 30 months. Ten patients (23%) underwent colposuspension. Fourteen patients (32%) claimed to be continent or so much improved that further treatment was considered unnecessary by the patients themselves. Of the remaining 20 patients who still claimed to have stress incontinence, 11 (25%) preferred to resume the pharmacological treatment whereas 9 patients (20%) had not decided whether they wanted further treatment. These results suggest that some operations for stress incontinence may be avoided by introduction of a standard trial of medical therapy prior to intended surgical intervention.

Norfenefrine in the treatment of female stress incontinence. A double-blind controlled trial

Forty-four consecutive patients with genuine stress incontinence were treated with norfenefrine 15-30 mg t.i.d. in a 6-week, double-blind and parallel, placebo-controlled study. Subjectively, 52% were improved and 26% became continent during norfenefrine treatment. Objectively (stress test), 30% became continent and the maximum urethral closure pressure increased 10% which was statistically significant. These results, however, were not statistically different from those of placebo treatment. Simultaneously, subjective and objective improvement was seen more often in patients given norfenefrine compared to placebo (p less than 0.1). In patients with most severe incontinence according to urodynamic criteria the effect of norfenefrine was statistically significantly better than placebo. A low incidence of side effects was observed and no differences between norfenefrine and placebo were found. It is concluded that norfenefrine may be of value in the treatment of female stress incontinence.