The Crystal Structure of the SV40 T-Antigen Origin Binding Domain in Complex with DNA

DNA replication is initiated upon binding of “initiators” to origins of replication. In simian virus 40 (SV40), the core origin contains four pentanucleotide binding sites organized as pairs of inverted repeats. Here we describe the crystal structures of the origin binding domain (obd) of the SV40 large T-antigen (T-ag) both with and without a subfragment of origin-containing DNA. In the co-structure, two T-ag obds are oriented in a head-to-head fashion on the same face of the DNA, and each T-ag obd engages the major groove. Although the obds are very close to each other when bound to this DNA target, they do not contact one another. These data provide a high-resolution structural model that explains site-specific binding to the origin and suggests how these interactions help direct the oligomerization events that culminate in assembly of the helicase-active dodecameric complex of T-ag

Patisiran, an RNAi therapeutic, for hereditary transthyretin amyloidosis

BACKGROUND Patisiran, an investigational RNA interference therapeutic agent, specifically inhibits hepatic synthesis of transthyretin. METHODS In this phase 3 trial, we randomly assigned patients with hereditary transthyretin amyloidosis with polyneuropathy, in a 2:1 ratio, to receive intravenous patisiran (0.3 mg per kilogram of body weight) or placebo once every 3 weeks. The primary end point was the change from baseline in the modified Neuropathy Impairment Score+7 (mNIS+7; range, 0 to 304, with higher scores indicating more impairment) at 18 months. Other assessments included the Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) questionnaire (range, −4 to 136, with higher scores indicating worse quality of life), 10-m walk test (with gait speed measured in meters per second), and modified body-mass index (modified BMI, defined as [weight in kilograms divided by square of height in meters]×albumin level in grams per liter; lower values indicated worse nutritional status). RESULTS A total of 225 patients underwent randomization (148 to the patisiran group and 77 to the placebo group). The mean (±SD) mNIS+7 at baseline was 80.9±41.5 in the patisiran group and 74.6±37.0 in the placebo group; the least-squares mean (±SE) change from baseline was −6.0±1.7 versus 28.0±2.6 (difference, −34.0 points; P<0.001) at 18 months. The mean (±SD) baseline Norfolk QOL-DN score was 59.6±28.2 in the patisiran group and 55.5±24.3 in the placebo group; the least-squares mean (±SE) change from baseline was −6.7±1.8 versus 14.4±2.7 (difference, −21.1 points; P<0.001) at 18 months. Patisiran also showed an effect on gait speed and modified BMI. At 18 months, the least-squares mean change from baseline in gait speed was 0.08±0.02 m per second with patisiran versus −0.24±0.04 m per second with placebo (difference, 0.31 m per second; P<0.001), and the least-squares mean change from baseline in the modified BMI was −3.7±9.6 versus −119.4±14.5 (difference, 115.7; P<0.001). Approximately 20% of the patients who received patisiran and 10% of those who received placebo had mild or moderate infusion-related reactions; the overall incidence and types of adverse events were similar in the two groups. CONCLUSIONS In this trial, patisiran improved multiple clinical manifestations of hereditary transthyretin amyloidosis

Q-TWiST Analysis of Patients Receiving Temsirolimus or Interferon Alpha for Treatment of Advanced Renal Cell Carcinoma

Background and Objective:Background and Objective: For patients with advanced cancers, it is important that treatment improves the quality as well as the quantity of survival. This quality-adjusted time without symptoms of progression or toxicity (Q-TWiST) analysis provides a combined measure of both the overall survival interval and the quality of survival for patients with advanced renal cell carcinoma (RCC) receiving temsirolimus, interferon (IFN)-α or the combination of these agents, using data from a phase III clinical trial. Abstract: Methods:Methods: Overall survival was partitioned into three distinct health states: time with serious toxicity (TOX), time after progression (REL) and time without symptoms of progression or toxicity (TWiST). Health states were quality weighted by patient-reported EQ-5D measures collected while receiving treatment. Abstract: Results:Results: All 626 patients from the trial were included in computation of health-state durations. EQ-5D questionnaires were obtained from 260 patients upon progression and from 230 after a grade 3 or 4 adverse event, and from 278 patients in the TWiST state. Patients receiving temsirolimus had 38% longer TWiST than those receiving IFNα (6.5 vs 4.7 months, respectively; p - 0.0005). Patients receiving temsirolimus had 25% longer quality-adjusted survival in terms of Q-TWiST than those receiving IFNα (7.0 vs 5.6 months, respectively; p - 0.0015). Differences between the combination (temsirolimus + IFNα) and IFNα groups were not statistically significant. Threshold utility analysis indicated that temsirolimus was the preferred alternative for all possible utility weights for REL and TOX health states. Abstract: Conclusion:Conclusion: Temsirolimus resulted in significantly longer Q-TWiST (quality-adjusted survival) in patients with advanced RCC than IFNα therapy.Interferon-alpha, therapeutic use, Quality-of-life, Renal-cell-carcinoma, treatment, Temsirolimus, therapeutic use, Utility-measurement

A Phase Ib Study of the VEGF Receptor Tyrosine Kinase Inhibitor Tivozanib and Modified FOLFOX-6 in Patients With Advanced Gastrointestinal Malignancies

Combining a modified (m)FOLFOX-6 (leucovorin, 5-fluorouracil [5-FU], and 85 mg/kg(2) oxaliplatin) regimen with antiangiogenic therapy is a standard treatment option in advanced colorectal cancer. In this phase Ib study, safety, pharmacokinetics, and antitumor activity of tivozanib with mFOLFOX-6 were assessed. Tivozanib could be combined at its recommended dose Of 1.5 mg with mFOLFOX-6, demonstrating antitumor activity, A randomized study in advanced colorectal Cancer comparing bevacizumab and tivozanib with mFOLFOX-6 has been performed. Background: Tivozanib hydrochloride (tivozanib) is a potent and selective tyrosine kinase inhibitor of all 3 vascular endothelial growth factor receptors with antitumor activity additive to 5-fluorouracil in preclinical models. This study was conducted to determine maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), pharmacokinetics (PKs), and antitumor activity of escalating doses of tivozanib with a modified (m)FOLFOX-6 (leucovorin, 5-fluorouracil [5-FU], and 85 mg/kg(2) oxaliplatin) regimen in patients with advanced gastrointestinal tumors. Patients and Methods: Tivozanib was administered orally once daily for 21 days in 28-day cycles, with mFOLFOX-6 administered every 14 days. Patients were allowed to continue tivozanib after discontinuation of mFOLFOX-6. Results: Thirty patients were assigned to tivozanib 0.5 mg (n = 9); 1.0 mg (n = 3); or 1.5 mg (n = 18) with mFOLFOX-6. Patients received a median of 5.2 (range, 0.03-26.9) months of tivozanib. DLTs were observed in 2 patients: Grade 3/4 transaminase level increases with tivozanib 0.5 mg, and Grade 3 dizziness with tivozanib 1.5 mg. Other Grade 3/4 adverse events included hypertension (n = 8); fatigue (n = 8), and neutropenia (n = 6): MTD for tivozanib with mFOLFOX-6 was confirmed as 1.5 mg. No PK interactions between tivozanib and mFOLFOX-6 were observed. One patient had an ongoing clinical complete response, 10 had a partial response, and 11 obtained prolonged stable disease. Conclusion: Tivozanib and mFOLFOX-6 is feasible and appears to be safe. The recommended dose for tivozanib with mFOLFOX-6 is 1.5 mg/d. Observed clinical activity merits further exploration in gastrointestinal tumors