Evaluation of infectivity and reverse transcriptase real-time polymerase chain reaction assays for detection of xenotropic murine leukemia virus used in virus clearance validation.

Infectivity and reverse transcriptase quantitative real-time polymerase chain reaction (qRT-PCR) assays have been optimized and validated for xenotropic murine leukemia virus (X-MuLV) detection. We have evaluated the assays systematically with regard to specificity, linearity, lower limit of detection (LLOD), lower limit of quantification (LLOQ), and precision. Both assays are specific for X-MuLV detection, with a linear detection range of 0.6-5.6 log(10) TCID(50)/mL for the infectivity assay, and 1.4-6.5 log(10) particles/mL for the qRT-PCR assay. The LLOD and LLOQ of the infectivity and the qRT-PCR assays are determined as 0.5 and 1.0 log(10)/mL, and 1.4 and 2.2 log(10)/mL. The inter-assay repeatability of qRT-PCR assay (4.2% coefficient of variation [CV]) is higher than the infectivity assay (7.9% CV). We have shown that both assays are closely correlated (r = 0.85, P < 0.05, n = 22). The particle/infectivity ratio is determined as 66. Both assays were applied to evaluate virus removal using virus clearance samples of chromatographic and filtration processes. Here, we have demonstrated that the qRT-PCR assay is much faster in testing and is approximately 8-fold more sensitive than the infectivity assay. Therefore, the qRT-PCR assay can replace the infectivity assay in many cases, but both assays are complementary in elucidating the mechanism of virus inactivation and removal in virus clearance validation.
Copyright © 2015 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

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Dose-Finding Quantitative 18F-FDG PET Imaging Study with the Oral Pan-AKT Inhibitor GSK2141795 in Patients with Gynecologic Malignancies.

AKT (a serine/threonine-specific protein kinase) regulates many cellular processes contributing to cytotoxic drug resistance. This study’s primary objective examined the relationship between GSK2141795, an oral, pan-AKT inhibitor, and (18)F-FDG PET markers of glucose metabolism in tumor tissue to determine whether (18)F-FDG PET could be used to guide personalized dosing of GSK2141795. Biomarker analysis of biopsies was also undertaken.
Twelve patients were enrolled in 3 cohorts; all underwent dynamic (18)F-FDG PET scans and serial pharmacokinetic sampling at baseline, week 2, and week 4 with tumor biopsies before treatment and at week 4. Response was evaluated by RECIST v1.1 and Gynecologic Cancer Intergroup criteria. Biopsy samples were analyzed for mutations and protein expression.
GSK2141795 did not significantly influence blood glucose levels. No dose-response relationship was observed between GSK2141795 pharmacokinetics and (18)F-FDG PET pharmacodynamic measures; however, an exposure-response relationship was seen between maximum drug concentrations and maximal decrease in (18)F-FDG uptake in the best-responding tumor. This relationship also held for pharmacokinetic parameters of exposure and 1,5-anhydroglucitol (a systemic measure of glucose metabolism). Phospho-AKT upregulation at week 4 in biopsies confirmed AKT inhibition by GSK2141795. Single-agent activity was observed with a clinical benefit rate of 27% (3/11) and 30% (3/10) CA125 response in the study’s platinum-resistant ovarian patients. AKT pathway activation by PIK3CA/PIK3R1 mutation did not correlate with clinical activity, whereas RAS/RAF pathway mutations did segregate with resistance to AKT inhibition.
GSK2141795 demonstrated an exposure-response relationship with decreased (18)F-FDG uptake and is active and tolerable. This study’s design integrating (18)F-FDG PET, pharmacokinetics, and biomarker analyses demonstrates the potential for clinical development for personalized treatment.
© 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

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Biofunctional Constituents from Michelia compressa var. lanyuensis with Anti-Melanogenic Properties.

Seven compounds were extracted and purified from the roots of Michelia compressa var. lanyuensis. These compounds are liriodenine, (-)-N-acetylanonaine, pressalanine A, p-dihydroxybenzaldehyde, 3,4-dihydroxybenzoic acid, (-)-bornesitol and β-sitostenone. These compounds were screened for anti-proliferation and anti-tyrosinase activities in B16F10 cells. Liriodenine, pressalanine A, (-)-bornesitol and β-sitostenone displayed cytotoxicity at high concentration (100 μM), but liriodenine (5 μM), (-)-N-acetylanonaine (10 μM), and β-sitostenone (5 μM) inhibit tyrosinase activity and reduce the melanin content in B16F10 cells without cytotoxicity, suggesting that liriodenine and β-sitostenone could be safe and potentially used in cosmetic skin whitening.

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Merck to Present New Data for KEYTRUDA® (pembrolizumab) at the American Association for Cancer Research 2016 Annual Meeting

On April 6, 2016 Merck (NYSE:MRK), known as MSD outside the United States and Canada, reported that new research investigating the use of KEYTRUDA (pembrolizumab), the company’s anti-PD-1 therapy, in multiple tumor types, both as a single agent and in combination with other therapies, will be presented at this year’s American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting in New Orleans, April 16 – 20 (Press release, Merck & Co, APR 6, 2016, View Source [SID:1234510458]).

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"The data being presented at AACR (Free AACR Whitepaper) reinforce our commitment to studying KEYTRUDA in a broad array of tumors and in a range of settings in order to fully understand its potential to improve long-term disease control and survival for people with cancer," said Dr. Eric Rubin, vice president and therapeutic area head, oncology early-stage development, Merck Research Laboratories. "As a leader in immuno-oncology, Merck continues to accelerate and further expand our clinical development program – with a goal to provide clinicians with data to understand the role of KEYTRUDA in a range of cancers."

The KEYTRUDA clinical research program currently includes more than 250 clinical trials in more than 30 tumor types, including more than 100 trials that combine KEYTRUDA with other cancer treatments. More than 30 registration-enabling trials evaluating KEYTRUDA as a single agent and in combination with other therapies are currently enrolling patients with bladder cancer, breast cancer, colorectal cancer, esophageal cancer, gastric cancer, head and neck cancer, Hodgkin lymphoma, melanoma, multiple myeloma, non-small cell lung cancer (NSCLC), and other tumors, with further trials in planning for other cancers. Several of the trials are being sponsored by the National Cancer Institute (NCI) under a Cooperative Research and Development Agreement with Merck.

The full listing of pembrolizumab abstracts and presentations at AACR (Free AACR Whitepaper) include:

Clinical Trials Plenary Sessions

(Abstract #CT004) KEYNOTE-006: PD-L1 expression and efficacy in patients (Pts) treated with pembrolizumab (pembro) vs ipilimumab (IPI) for advanced melanoma. M. Carlino. Sunday, April 17, 2:15 p.m. – 4:00 p.m. CDT. Location: La Nouvelle Ballroom, Morial Convention Center.
(Abstract #CT096) Clinical activity, immune and viral correlates of PD-1 blockade with pembrolizumab as first systemic therapy in patients with advanced Merkel cell carcinoma. CITN-09. P. Nghiem. Tuesday, April 19, 10:30 a.m. – 12:15 p.m. CDT. Location: Room 391, Morial Convention Center. (NCI-sponsored trial).
Poster Sessions

(Abstract #543) Preclinical combination strategies to enhance the efficacy of the anti-PD-1 antibody pembrolizumab. E. Pinheiro. Sunday, April 17, 1:00 p.m. – 5:00 p.m. CDT. Location: Section 26, Morial Convention Center.
(Abstract #562) Dinaciclib induces immunogenic cell death and enhances anti-PD-1 mediated tumor suppression. D. Hossain. Sunday, April 17, 1:00 p.m. – 5:00 p.m. CDT. Location: Section 26, Morial Convention Center.
(Abstract #CT027) A phase I, open-label study of GSK3174998 administered alone and in combination with pembrolizumab in patients (pts) with selected advanced solid tumors (ENGAGE-1). J. Infante. Monday, April 18, 8:00 a.m. – 12:00 p.m. CDT. Location: Section 13, Morial Convention Center.
(Abstract #CT112) Exposure-response analysis of pembrolizumab in patients with advanced melanoma and non-small cell lung cancer enrolled in KEYNOTE-001, -002, and -006. M. Chatterjee. Tuesday, April 19, 1:00 p.m. – 5:00 p.m. CDT. Location: Section 13, Morial Convention Center.
(Abstract #CT125) A phase III randomized trial comparing FDA approved standard of care adjuvant therapy to one year of pembrolizumab in patients with high risk resected melanoma. SWOG 1404. K. Grossmann. Tuesday, April 19, 1:00 p.m. – 5:00 p.m. CDT. Location: Section 13, Morial Convention Center. (NCI-sponsored trial).
(Abstract #4359) Rescue of exhausted CD8 T cells by PD-1 targeted therapies is CD28-dependent. A. Kamphorst. Tuesday, April 19, 3:05 p.m. – 3:20 p.m. CDT. Location: New Orleans Theater C, Morial Convention Center.
(Abstract #4989) Toxicity profile of contemporaneous PD-1 inhibitor immunotherapy and radiotherapy. T. Wilhite. Wednesday, April 20, 8:00 a.m. – 12:00 p.m. CDT. Location: Section 26, Morial Convention Center.
About KEYTRUDA (pembrolizumab) Injection 100 mg

KEYTRUDA is a humanized monoclonal antibody that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. KEYTRUDA blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells.

KEYTRUDA is indicated in the United States for the treatment of patients with unresectable or metastatic melanoma.

KEYTRUDA is also indicated for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors express PD-L1 as determined by an FDA-approved test with disease progression on or after platinum-containing chemotherapy. Patients with EGFR or ALK genomic tumor aberrations should have disease progression on FDA-approved therapy for these aberrations prior to receiving KEYTRUDA. The NSCLC indication is approved under accelerated approval based on tumor response rate and durability of response. An improvement in survival or disease-related symptoms has not yet been established. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

KEYTRUDA is administered at a dose of 2 mg/kg as an intravenous infusion over 30 minutes every three weeks for the approved indications.

Selected Important Safety Information for KEYTRUDA (pembrolizumab)

Immune-mediated pneumonitis, including fatal cases, occurred in patients receiving KEYTRUDA. Pneumonitis occurred in 32 (2%) of 1,567 patients with melanoma, including Grade 1 (0.8%), 2 (0.8%), and 3 (0.4%) pneumonitis. Pneumonitis occurred in 19 (3.5%) of 550 patients with non-small cell lung cancer (NSCLC), including Grade 2 (1.1%), 3 (1.3%), 4 (0.4%), or 5 (0.2%) pneumonitis and more frequently in patients with a history of asthma/chronic obstructive pulmonary disease (5.4%) or prior thoracic radiation (6.0%). Monitor patients for signs and symptoms of pneumonitis. Evaluate suspected pneumonitis with radiographic imaging. Administer corticosteroids for Grade 2 or greater pneumonitis. Withhold KEYTRUDA for Grade 2; permanently discontinue KEYTRUDA for Grade 3 or 4 or recurrent Grade 2 pneumonitis.

Immune-mediated colitis occurred in 31 (2%) of 1,567 patients with melanoma, including Grade 2 (0.5%), 3 (1.1%), and 4 (0.1%) colitis. Immune-mediated colitis occurred in 4 (0.7%) of 550 patients with NSCLC, including Grade 2 (0.2%) or 3 (0.4%) colitis. Monitor patients for signs and symptoms of colitis. Administer corticosteroids for Grade 2 or greater colitis. Withhold KEYTRUDA for Grade 2 or 3; permanently discontinue KEYTRUDA for Grade 4 colitis.

Immune-mediated hepatitis occurred in 16 (1%) of 1,567 patients with melanoma, including Grade 2 (0.1%), 3 (0.7%), and 4 (0.1%) hepatitis. Monitor patients for changes in liver function. Administer corticosteroids for Grade 2 or greater hepatitis and, based on severity of liver enzyme elevations, withhold or discontinue KEYTRUDA.

Hypophysitis occurred in 13 (0.8%) of 1,567 patients with melanoma, including Grade 2 (0.3%), 3 (0.3%), and 4 (0.1%) hypophysitis. Hypophysitis occurred in 1 (0.2%) of 550 patients with NSCLC, which was Grade 3 in severity. Monitor patients for signs and symptoms of hypophysitis (including hypopituitarism and adrenal insufficiency). Administer corticosteroids and hormone replacement as clinically indicated. Withhold KEYTRUDA for Grade 2; withhold or discontinue for Grade 3 or 4 hypophysitis.

Hyperthyroidism occurred in 51 (3.3%) of 1,567 patients with melanoma, including Grade 2 (0.6%) and 3 (0.1%) hyperthyroidism. Hypothyroidism occurred in 127 (8.1%) of 1,567 patients with melanoma, including Grade 3 (0.1%) hypothyroidism. Hyperthyroidism occurred in 10 (1.8%) of 550 patients with NSCLC, including Grade 2 (0.7%) or 3 (0.3%) hyperthyroidism. Hypothyroidism occurred in 38 (6.9%) of 550 patients with NSCLC, including Grade 2 (5.5%) or 3 (0.2%) hypothyroidism. Thyroid disorders can occur at any time during treatment. Monitor patients for changes in thyroid function (at the start of treatment, periodically during treatment, and as indicated based on clinical evaluation) and for clinical signs and symptoms of thyroid disorders. Administer replacement hormones for hypothyroidism and manage hyperthyroidism with thionamides and beta-blockers as appropriate. Withhold or discontinue KEYTRUDA (pembrolizumab) for Grade 3 or 4 hyperthyroidism.

Type 1 diabetes mellitus, including diabetic ketoacidosis, occurred in 3 (0.1%) of 2,117 patients. Monitor patients for hyperglycemia or other signs and symptoms of diabetes. Administer insulin for type 1 diabetes, and withhold KEYTRUDA and administer anti-hyperglycemics in patients with severe hyperglycemia.

Immune-mediated nephritis occurred in 7 (0.4%) of 1,567 patients with melanoma, including Grade 2 (0.2%), 3 (0.2%) and Grade 4 (0.1%) nephritis. Monitor patients for changes in renal function. Administer corticosteroids for Grade 2 or greater nephritis. Withhold KEYTRUDA for Grade 2; permanently discontinue KEYTRUDA for Grade 3 or 4 nephritis.

Other clinically important immune-mediated adverse reactions can occur. For suspected immune-mediated adverse reactions, ensure adequate evaluation to confirm etiology or exclude other causes. Based on the severity of the adverse reaction, withhold KEYTRUDA and administer corticosteroids. Upon improvement to Grade 1 or less, initiate corticosteroid taper and continue to taper over at least 1 month. Based on limited data from clinical studies in patients whose immune-related adverse reactions could not be controlled with corticosteroid use, administration of other systemic immunosuppressants can be considered. Resume KEYTRUDA when the immune-mediated adverse reaction remains at Grade 1 or less following corticosteroid taper. Permanently discontinue KEYTRUDA for any Grade 3 immune-mediated adverse reaction that recurs and for any life-threatening immune-mediated adverse reaction.

The following clinically significant, immune-mediated adverse reactions occurred in less than 1% (unless otherwise indicated) of 1567 patients with melanoma: arthritis (1.6%), exfoliative dermatitis, bullous pemphigoid, uveitis, myositis, Guillain-Barré syndrome, myasthenia gravis, vasculitis, pancreatitis, hemolytic anemia, and partial seizures arising in a patient with inflammatory foci in brain parenchyma. The following clinically significant, immune-mediated adverse reactions occurred in less than 1% of 550 patients with NSCLC: rash, vasculitis, hemolytic anemia, serum sickness, and myasthenia gravis.

Severe and life-threatening infusion-related reactions have been reported in 3 (0.1%) of 2,117 patients. Monitor patients for signs and symptoms of infusion related reactions including rigors, chills, wheezing, pruritus, flushing, rash, hypotension, hypoxemia, and fever. For Grade 3 or 4 reactions, stop infusion and permanently discontinue KEYTRUDA.

Based on its mechanism of action, KEYTRUDA can cause fetal harm when administered to a pregnant woman. If used during pregnancy, or if the patient becomes pregnant during treatment, apprise the patient of the potential hazard to a fetus. Advise females of reproductive potential to use highly effective contraception during treatment and for 4 months after the last dose of KEYTRUDA (pembrolizumab).

In Trial 6, KEYTRUDA was discontinued due to adverse reactions in 9% of 555 patients with advanced melanoma; adverse reactions leading to discontinuation in more than one patient were colitis (1.4%), autoimmune hepatitis (0.7%), allergic reaction (0.4%), polyneuropathy (0.4%), and cardiac failure (0.4%). Adverse reactions leading to interruption of KEYTRUDA occurred in 21% of patients; the most common (≥1%) was diarrhea (2.5%). The most common adverse reactions with KEYTRUDA vs. ipilimumab were fatigue (28% vs. 28%), diarrhea (26% with KEYTRUDA), rash (24% vs. 23%), and nausea (21% with KEYTRUDA). Corresponding incidence rates are listed for ipilimumab only for those adverse reactions that occurred at the same or lower rate than with KEYTRUDA.

In Trial 2, KEYTRUDA was discontinued due to adverse reactions in 12% of 357 patients with advanced melanoma; the most common (≥1%) were general physical health deterioration (1%), asthenia (1%), dyspnea (1%), pneumonitis (1%), and generalized edema (1%). Adverse reactions leading to interruption of KEYTRUDA occurred in 14% of patients; the most common (≥1%) were dyspnea (1%), diarrhea (1%), and maculo-papular rash (1%). The most common adverse reactions with KEYTRUDA vs. chemotherapy were fatigue (43% with KEYTRUDA), pruritus (28% vs. 8%), rash (24% vs. 8%), constipation (22% vs. 20%), nausea (22% with KEYTRUDA), diarrhea (20% vs. 20%), and decreased appetite (20% with KEYTRUDA). Corresponding incidence rates are listed for chemotherapy only for those adverse reactions that occurred at the same or lower rate than with KEYTRUDA.

KEYTRUDA was discontinued due to adverse reactions in 14% of 550 patients with NSCLC. Serious adverse reactions occurred in 38% of patients. The most frequent serious adverse reactions reported in 2% or more of patients were pleural effusion, pneumonia, dyspnea, pulmonary embolism, and pneumonitis. The most common adverse reactions (reported in at least 20% of patients) were fatigue (44%), decreased appetite (25%), cough (29%), and dyspnea (23%).

No formal pharmacokinetic drug interaction studies have been conducted with KEYTRUDA.

It is not known whether KEYTRUDA is excreted in human milk. Because many drugs are excreted in human milk, instruct women to discontinue nursing during treatment with KEYTRUDA and for 4 months after the final dose.

Safety and effectiveness of KEYTRUDA have not been established in pediatric patients.

Our Focus on Cancer

Our goal is to translate breakthrough science into innovative oncology medicines to help people with cancer worldwide. At Merck Oncology, helping people fight cancer is our passion and supporting accessibility to our cancer medicines is our commitment. Our focus is on pursuing research in immuno-oncology and we are accelerating every step in the journey – from lab to clinic – to potentially bring new hope to people with cancer. For more information about our oncology clinical trials, visit www.merck.com/clinicaltrials.

Antibody-Mediated Phosphatidylserine Blockade Enhances the Antitumor Responses to CTLA-4 and PD-1 Antibodies in Melanoma.

In tumor bearing animals, the membrane phospholipid phosphatidylserine (PS) suppresses immune responses, suggesting that PS signaling could counteract the antitumor effect of antibody-driven immune checkpoint blockade. Here we show that treating melanoma-bearing mice with a PS-targeting antibody enhances the antitumor activity of downstream checkpoint inhibition. Combining PS-targeting antibodies with CTLA-4 or PD-1 blockade resulted in significantly greater inhibition of tumor growth than did single agent therapy. Moreover, combination therapy enhanced CD4+ and CD8+ tumor-infiltrating lymphocyte numbers; elevated the fraction of cells expressing the pro-inflammatory cytokines IL2, IFNγ, and TNFα; and increased the ratio of CD8 T cells to myeloid-derived suppressor cells and regulatory T cells in tumors. Similar changes in immune cell profiles were observed in splenocytes. Taken together, these data show that antibody-mediated PS blockade enhances the antitumor efficacy of immune checkpoint inhibition.
Copyright ©2016, American Association for Cancer Research (AACR) (Free AACR Whitepaper).

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