Real-world evidence analysis of palbociclib prescribing patterns for patients with advanced/metastatic breast cancer treated in community oncology practice in the USA one year post approval.

BACKGROUND: Rapidly evolving understanding of cancer biology has presented novel opportunities to translate that understanding into clinically relevant therapy. Palbociclib, a novel, first-in-class cyclin-dependent kinase (CDK) 4/6 inhibitor was approved in the USA in February 2015 for the treatment of advanced/metastatic breast cancer. We examined real-world evidence in the first year post approval to understand the clinical and demographic characteristics of patients treated with palbociclib in community oncology practices and the dosing, treatment, and complete blood count (CBC) monitoring patterns. METHODS: This was a retrospective observational study of structured data from a US electronic medical record (EMR) database. Female patients receiving palbociclib after 31 January 2015 were followed through 31 March 2016. Our methodological rules were constructed to aggregate drugs received according to the order in which they are given, i.e., identify the line of therapy as first, second, or third line, etc., using treatment order and course description fields from the EMR. RESULTS: There were 763 patients initiating palbociclib who met the selection criteria. Of those, 612 (80.2%) received palbociclib concomitantly with letrozole. Mean follow up was 6.4 months and mean age at palbociclib initiation was 64 years. Of patients with a known starting dose (n = 417), 79.9% started on palbociclib 125 mg. Dose reductions were observed in 20.1% of patients. Percentages of patients according to line of therapy at initiation of palbociclib were first-line, 39.5%; second-line, 15.7%; third-line, 13.1%; and fourth-line therapy or later, 31.7%. On average, two CBC tests were conducted during the first cycle of palbociclib treatment. Overall, 74.6% of patients had a neutropenic event during follow up including 47.3% and 8.0% of patients with a grade 3 or 4 occurrence, respectively. CONCLUSIONS: Real-world palbociclib use one year post US approval demonstrates a more heterogeneous patient population than that studied in the clinical trials with more than half of the patients receiving palbociclib plus letrozole in later lines of therapy. CBC testing rates suggested good provider compliance with monitoring guidelines in the USA prescribing information. The occurrence of grade 3 and 4 neutropenia (based on laboratory results) was consistent with the rates of grade 3 and 4 neutropenia in two phase-III studies (PALOMA-2, 56% and 10%; PALOMA-3, 55% and 11%, respectively). Understanding palbociclib utilization in real-world patients and how drug dosing and monitoring are performed aids in the understanding of safe and effective use of the drug.

Compared Methods for Reducing Stress in ROP Exams; Stake-Holding Examiner Perspective.

Purpose: To better understand the sensory impact of retinal exam components typically experienced by infants undergoing various retinopathy of prematurity staging examinations, adults concerned for infant welfare and exam quality underwent similar exams to compare their perceived stress. Patients and Methods: Adults directly involved with ROP exams and infant stress reduction had cardiac monitoring and concomitant ordinal self symptom-score (1-10 Likert) during 15 components of the exam including lid speculum, various scleral depressors, indirect ophthalmoscopy, goniolens and direct ophthalmoscopy and retinal photography (Phoenix ICON) with or without topical anesthesia. Results: Nine adults provided impressions and cardiac rhythm gathered supine over 15 minutes. Pain score for topical anesthetic 2 was less than for tropicamide 4. Lid specula numb scored a median 2 level (from 1 to 10) pain but without anesthetic scored 6. The goniolens numb scored 3. Scleral depression numb scored 3-4 but increased to 7 without topical anesthesia. Direct ophthalmoscope scored 3 through the goniolens and the retinal camera scored 4 pain. Brightness with low 350 Lux indirect scored 6-8 numb and 9 brightness without anesthetic. Full bright indirect, direct ophthalmoscope and the retinal camera all had Lux of 3000-4000 and were scored brightness 9, 7 and 10, respectively. Adults had minimal oculocardiac reflex during on-globe retinal examination methods (range 98% to 102%). Conclusion: Topical anesthesia provided a moderate reduction in pain during on-globe lid-speculum, scleral depressed indirect examination. There was a synergistic augmented sensory response between pain and brightness. Adults did not show the bradycardia typically elicited by retinal examinations in premature infants.

Use of fiberoptic endoscopy in diagnosis and therapy of upper gastrointestinal disorders.

The future role of therapeutic endoscopy appears bright and depends on the possibilities of technology and the ingenuity of those performing the procedures. New techniques are being devised, and the therapeutic applications are being evaluated continually. Such issues as appropriate indications, efficacy, and cost-effectiveness remain important considerations for the practitioner dealing with gastrointestinal disorders.

A comparison of two techniques for attaining root coverage.

This study compared the relative success of soft tissue coverage of denuded roots by two surgical procedures: Autogenous free gingival graft (FGG) and a 2-stage coronally-positioned flap (CPF). Eight patients who had bilateral areas of gingival recession were selected. The areas of recession treated were Class I or II according to Miller's classification and caused either an esthetic problem or root sensitivity. The defects were randomly assigned to surgical procedures in each subject. In the FGG, the root surfaces were root planed, conditioned with a saturated citric acid solution, and an adjacent recipient site was prepared surgically. A thick palatal graft was then sutured to the recipient site. In the CPF, an initial autogenous free gingival graft was surgically placed in a recipient site just apical to the root recession. After 1 month of healing, the gingiva was coronally positioned to the level of the CEJ. Standardized photographs were obtained presurgically, at 2 weeks, and at 1 and 3 months. Reduction of areas of exposed root surface and distances from CEJ to gingival margin were computed. Data analysis did not demonstrate a significant difference in success between FGG and CPF at 3 months. Maximum decrease of exposed root surfaces occurred at 2 weeks postsurgically with both procedures and then some recession of each type of graft occurred. The mean distance of the exposed root surfaces decreased from 2.136 mm to 1.301 mm and from 2.187 mm to 1.400 from baseline to 3 months for the FGG and CPF respectively.

zeste, a nonessential gene, potently activates Ultrabithorax transcription in the Drosophila embryo.

The GAGA, NTF-1, and zeste proteins have been purified previously from Drosophila embryo extracts and shown to activate the Ultrabithorax (Ubx) promoter in vitro. Here, differently mutated Ubx-promoter constructs containing binding sites for none, one, or all three of these transcription factors have been introduced into Drosophila by P-element transformation. Binding sites for each factor activate dramatically different patterns of transcription. In zeste mutant embryos, the activation by zeste protein-binding sites is essentially abolished. These genetic data, when considered with our earlier biochemical experiments, demonstrate that zeste directly and potently activates Ubx transcription in vivo. Surprisingly, previous genetic experiments indicate that zeste is a nonessential gene shown only to act in a dispensable regulatory process termed transvection. In our transgenic experiments, zeste is not activating transcription by transvection. We propose that the function of zeste in Drosophila is much broader than assumed previously, and that it is a member of a redundant system of transcription factors that regulate and maintain the expression of Ubx and other Drosophila genes.

Redundant control of Ultrabithorax by zeste involves functional levels of zeste protein binding at the Ultrabithorax promoter.

Many biological processes appear to be controlled by functionally redundant genes or pathways, but it has proven difficult to understand the nature of this redundancy. Here, we have analyzed a redundant regulatory interaction between the Drosophila transcription factor zeste and the homeotic gene Ultrabithorax. Mutations in zeste do not affect the cis-regulation of the endogenous Ultrabithorax gene; however, the expression of small Ultrabithorax promoter constructs is strongly dependent upon zeste. We show that this difference is due to redundant cis-regulatory elements in the Ultrabithorax gene, which presumably contain binding sites for factors that share the function of zeste. We also provide evidence suggesting that zeste and the gene encoding the GAGA factor have an overlapping function in regulating Ultrabithorax. Furthermore, we show that the zeste protein is bound at equal levels in vivo to a Ultrabithorax promoter construct, which zeste strongly activates, and to the identical promoter region in the endogenous Ultrabithorax gene, which zeste redundantly regulates. These results suggest that zeste is significantly active in the wild-type animal and not simply a factor that is induced as a back-up when other activators fail.

Zeste-mediated activation by an enhancer is independent of cooperative DNA binding in vivo.

It is not clear how transcription factors bound at distal enhancer and proximal promoter sequences cooperate to stimulate transcription in vivo. To distinguish between different models for the action of enhancer elements, we have directly measured DNA binding of the Drosophila activator zeste by in vivo UV crosslinking. Experiments in Drosophila embryos show that binding of zeste protein to either the proximal promoter of the Ultrabithorax (Ubx) gene or to a Ubx enhancer element does not require the presence of the other element. However, significant transcription is observed only when both elements are present and bound by zeste. The results indicate that stimulation by an enhancer can occur by a mechanism other than increasing the occupancy of an activator to binding sites near the start site of transcription.

The Saccharomyces cerevisiae ubiquitin-proteasome system.

Our studies of the yeast ubiquitin-proteasome pathway have uncovered a number of general principles that govern substrate selectivity and proteolysis in this complex system. Much of the work has focused on the destruction of a yeast transcription factor, MAT alpha 2. The alpha 2 protein is polyubiquitinated and rapidly degraded in alpha-haploid cells. One pathway of proteolytic targeting, which depends on two distinct endoplasmic reticulum-localized ubiquitin-conjugating enzymes, recognizes the hydrophobic face of an amphipathic helix in alpha 2. Interestingly, degradation of alpha 2 is blocked in a/alpha-diploid cells by heterodimer formation between the alpha 2 and a1 homeodomain proteins. The data suggest that degradation signals may overlap protein-protein interaction surfaces, allowing a straightforward steric mechanism for regulated degradation. Analysis of alpha 2 degradation led to the identification of both 20S and 26S proteasome subunits, and several key features of proteasome assembly and active-site formation were subsequently uncovered. Finally, it has become clear that protein (poly) ubiquitination is highly dynamic in vivo, and our studies of yeast de-ubiquitinating enzymes illustrate how such enzymes can facilitate the proteolysis of diverse substrates.