A phase 2 study of panitumumab with irinotecan as salvage therapy in chemorefractory KRAS exon 2 wild-type metastatic colorectal cancer patients.

BACKGROUND: Targeted agents are standard treatment for RAS wild-type metastatic colorectal cancer in the first- and second-line settings. This phase 2 study determined the benefit of targeting the epidermal growth factor receptor (EGFR) with panitumumab plus irinotecan in irinotecan-refractory patients. METHODS: KRAS exon-2 wild-type patients failing prior irinotecan received panitumumab (6 mg/kg) and irinotecan (180 mg/m²) every 2 weeks. The primary endpoint was the overall response rate (ORR). Secondary endpoints included safety, progression-free survival (PFS) and overall survival (OS). KRAS exon-2 status was evaluated centrally, along with NRAS, BRAF mutations, epiregulin, amphiregulin, PTEN and EGFR copy number status, and correlated with efficacy. RESULTS: Sixty-one patients were treated. Among the 46 wild-type RAS patients, the ORR was 15.2% (seven partial responses), with median PFS of 3.8 months (95% CI 2.7-4.3) and median OS of 12.5 months (95% CI 6.7-15.9). Wild-type BRAF patients showed a 13.0% response rate. No significant correlations between response and baseline biomarker expression were identified. Common grade 3-4 adverse events were diarrhoea and rash (18.0% each), hypomagnesaemia and asthenia (8.2% each). CONCLUSIONS: The addition of panitumumab to irinotecan as salvage therapy is feasible but has limited activity in irinotecan-refractory metastatic colorectal cancer. No biomarkers predictive of response were identified.

Single-Agent Regorafenib in Metastatic Colorectal Cancer Patients with Any RAS or BRAF Mutation Previously Treated with FOLFOXIRI plus Bevacizumab (PREVIUM Trial).

LESSONS LEARNED: RAS- or BRAF-mutated metastatic colorectal cancers (mCRCs) progressing after first-line treatment have a poor prognosis.European and U.S. guidelines include the multikinase inhibitor regorafenib as a standard option for second-line therapy and beyond, based on the results of the randomized phase III CORRECT trial demonstrating improvement in survival.Although stopped prematurely for failing to accrue, the PREVIUM trial, the first prospective interventional study exploring regorafenib as second-line treatment for patients with mCRC bearing RAS or BRAF mutations, failed to demonstrate clinical activity in the population analyzed. BACKGROUND: Patients with RAS- or BRAF-mutated (mut) metastatic colorectal cancer (mCRC) progressing on first-line bevacizumab plus 5-FU/irinotecan/oxaliplatin (FOLFOXIRI) have a poor prognosis. We aimed to assess the efficacy and safety of regorafenib in this population. METHODS: Regorafenib was administered daily for 3 weeks of each 4-week cycle until disease progression or other reason. The primary endpoint was 6-month progression-free survival (PFS). RESULTS: KRAS, NRAS, or BRAF was mutated in mCRC samples in 60%, 20%, and 13% of patients, respectively. Median time from initial diagnosis of metastases to the start of regorafenib and treatment duration was 13.8 months and 7 weeks, respectively. Reasons for discontinuation included disease progression (80%), investigator decision (13%), and adverse events (AEs; 7%). Seven patients (47%) required dose reduction, mostly for asthenia (43%). The most common regorafenib-related grade 3 AEs were asthenia (33%), dysphonia (13%), and hypertension (13%) (Table 1). There were no grade 4 toxicities. No patient was progression-free at 6 months. Median PFS, time to progression (TTP), and overall survival (OS) were 2.2, 2.0, and 3.3 months, respectively. CONCLUSION: Although stopped prematurely for failing to accrue, in the population analyzed, regorafenib failed to demonstrate clinical activity in KRAS- or BRAF-mutated mCRC with progression following first-line with FOLFOXIRI plus bevacizumab, although tolerability was acceptable. Our trial suggests that exploring regorafenib efficacy in an earlier line of therapy should not be undertaken without better population refinement.

Nanoparticles engineered to bind cellular motors for efficient delivery.

BACKGROUND: Dynein is a cytoskeletal molecular motor protein that transports cellular cargoes along microtubules. Biomimetic synthetic peptides designed to bind dynein have been shown to acquire dynamic properties such as cell accumulation and active intra- and inter-cellular motion through cell-to-cell contacts and projections to distant cells. On the basis of these properties dynein-binding peptides could be used to functionalize nanoparticles for drug delivery applications. RESULTS: Here, we show that gold nanoparticles modified with dynein-binding delivery sequences become mobile, powered by molecular motor proteins. Modified nanoparticles showed dynamic properties, such as travelling the cytosol, crossing intracellular barriers and shuttling the nuclear membrane. Furthermore, nanoparticles were transported from one cell to another through cell-to-cell contacts and quickly spread to distant cells through cell projections. CONCLUSIONS: The capacity of these motor-bound nanoparticles to spread to many cells and increasing cellular retention, thus avoiding losses and allowing lower dosage, could make them candidate carriers for drug delivery.

C-NH2 bond formation mediated by iridium complexes.

In the presence of phosphanes (PR3 ), the amido-bridged trinuclear complex [{Ir(µ-NH2 )(tfbb)}3 ] (tfbb=tetrafluorobenzobarrelene) transforms into mononuclear discrete compounds [Ir(1,2-η(2) -4-κ-C12 H8 F4 N)(PR3 )3 ], which are the products of the CN coupling between the amido moiety and a vinylic carbon of the diolefin. An alternative synthetic approach to these species involves the reaction of the 18 e(-) complex [Ir(Cl)(tfbb)(PMePh2 )2 ] with gaseous ammonia and additional phosphane. DFT studies show that both transformations occur through nucleophilic attack. In the first case the amido moiety attacks a diolefin coordinated to a neighboring molecule following a bimolecular mechanism induced by the highly basic NH2 moiety; the second pathway involves a direct nucleophilic attack of ammonia to a coordinated tfbb molecule.

Nab-Paclitaxel plus Gemcitabine and FOLFOX in Metastatic Pancreatic Cancer.

BACKGROUND: Sequential nab-paclitaxel plus gemcitabine followed by modified FOLFOX-6 (oxaliplatin, leucovorin, and 5-fluorouracil) (nab-P/Gem-mFOLFOX) showed a good safety and clinical profile in metastatic pancreatic ductal adenocarcinoma (mPDAC) in the phase I SEQUENCE trial. METHODS: The safety and efficacy of sequential nab-P/Gem-mFOLFOX was compared with standard nab-paclitaxel plus gemcitabine (nab-P/Gem) as first-line treatment in a multi-institutional, randomized, open-label, phase II trial in patients with untreated mPDAC. We randomly assigned patients in a 1:1 ratio to receive nab-P/Gem on days 1, 8, and 15 followed by mFOLFOX on day 29 of a 6-week cycle (experimental group) or nab-P/Gem on days 1, 8, and 15 of a 4-week cycle (control group). The primary end point was the 12-month overall survival rate. RESULTS: A total of 157 patients were randomly assigned: 78 to nab-P/Gem-mFOLFOX and 79 to nab-P/Gem. Patients receiving nab-P/Gem-mFOLFOX had a 12-month overall survival of 55.3% (95% confidence interval [CI], 44.2 to 66.5) versus 35.4% (95% CI, 24.9 to 46) in the control group (P=0.02). Similarly, the 24-month survival was 22.4% (95% CI, 13 to 31.8) with nab-P/Gem-mFOLFOX versus 7.6% (95% CI, 1.8 to 13.4) with control treatment. The median overall survival was 13.2 months (95% CI, 10.1 to 16.2) with nab-P/Gem-mFOLFOX and 9.7 months (95% CI, 7.5 to 12) with nab-P/Gem (hazard ratio for death, 0.68; 95% CI, 0.48 to 0.95). The safety profile showed a higher incidence of grade 3 or higher neutropenia (35 of 76 vs. 19 of 79 patients, P=0.004), grade 3 or higher thrombocytopenia (18 of 78 vs. 6 of 79 patients, P=0.007), and two treatment-related deaths (2.6%) with nab-P/Gem-mFOLFOX compared with none with control treatment. CONCLUSIONS: Sequential nab-P/Gem-mFOLFOX showed a significantly higher 12-month survival when compared with the standard nab-P/Gem treatment; this came with greater treatment toxicity. (Funded by Celgene; EuCT number, 2014-005350-19; ClinicalTrials.gov number, NCT02504333.)

Terminal and bridging parent amido 1,5-cyclooctadiene complexes of rhodium and iridium.

The ready availability of rare parent amido d(8) complexes of the type [{M(µ-NH2)(cod)}2] (M=Rh (1), Ir (2); cod=1,5-cyclooctadiene) through the direct use of gaseous ammonia has allowed the study of their reactivity. Both complexes 1 and 2 exchanged the di-olefines by carbon monoxide to give the dinuclear tetracarbonyl derivatives [{M(µ-NH2)(CO)2}2 ] (M=Rh or Ir). The diiridium(I) complex 2 reacted with chloroalkanes such as CH2Cl2 or CHCl3, giving the diiridium(II) products [(Cl)(cod)Ir(µ-NH2)2Ir(cod)(R)] (R=CH2Cl or CHCl2) as a result of a two-center oxidative addition and concomitant metal-metal bond formation. However, reaction with ClCH2CH2Cl afforded the symmetrical adduct [{Ir(µ-NH2)(Cl)(cod)}2] upon release of ethylene. We found that the rhodium complex 1 exchanged the di-olefines stepwise upon addition of selected phosphanes (PPh3, PMePh2, PMe2Ph) without splitting of the amido bridges, allowing the detection of mixed COD/phosphane dinuclear complexes [(cod)Rh(µ-NH2)2Rh(PR3)2], and finally the isolation of the respective tetraphosphanes [{Rh(µ-NH2)(PR3)2}2]. On the other hand, the iridium complex 2 reacted with PMe2 Ph by splitting the amido bridges and leading to the very rare terminal amido complex [Ir(cod)(NH2)(PMePh2)2]. This compound was found to be very reactive towards traces of water, giving the more stable terminal hydroxo complex [Ir(cod)(OH)(PMePh2)2]. The heterocyclic carbene IPr (IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) also split the amido bridges in complexes 1 and 2, allowing in the case of iridium to characterize in situ the terminal amido complex [Ir(cod)(IPr)(NH2)]. However, when rhodium was involved, the known hydroxo complex [Rh(cod)(IPr)(OH)] was isolated as final product. On the other hand, we tested complexes 1 and 2 as catalysts in the transfer hydrogenation of acetophenone with iPrOH without the use of any base or in the presence of Cs2CO3, finding that the iridium complex 2 is more active than the rhodium analogue 1.

HLA-A*02:1093, a variant of HLA-A*02:01:01:01 detected in two Spanish individuals.

A change in one nucleotide in codon 193 of HLA-A*02:01:01:01 results in the new allele HLA-A*02:1093.

Effect of fixation on brain and lymphoreticular vCJD prions and bioassay of key positive specimens from a retrospective vCJD prevalence study.

Anonymous screening of lymphoreticular tissues removed during routine surgery has been applied to estimate the UK population prevalence of asymptomatic vCJD prion infection. The retrospective study of Hilton et al (J Pathol 2004; 203: 733-739) found accumulation of abnormal prion protein in three formalin-fixed appendix specimens. This led to an estimated UK prevalence of vCJD infection of ∼1 in 4000, which remains the key evidence supporting current risk reduction measures to reduce iatrogenic transmission of vCJD prions in the UK. Confirmatory testing of these positives has been hampered by the inability to perform immunoblotting of formalin-fixed tissue. Animal transmission studies offer the potential for 'gold standard' confirmatory testing but are limited by both transmission barrier effects and known effects of fixation on scrapie prion titre in experimental models. Here we report the effects of fixation on brain and lymphoreticular human vCJD prions and comparative bioassay of two of the three prevalence study formalin-fixed, paraffin-embedded (FFPE) appendix specimens using transgenic mice expressing human prion protein (PrP). While transgenic mice expressing human PrP 129M readily reported vCJD prion infection after inoculation with frozen vCJD brain or appendix, and also FFPE vCJD brain, no infectivity was detected in FFPE vCJD spleen. No prion transmission was observed from either of the FFPE appendix specimens. The absence of detectable infectivity in fixed, known positive vCJD lymphoreticular tissue precludes interpreting negative transmissions from vCJD prevalence study appendix specimens. In this context, the Hilton et al study should continue to inform risk assessment pending the outcome of larger-scale studies on discarded surgical tissues and autopsy samples.

Di-µ-methanolato-bis[(η4-tetrafluorobenzobarrelene)rhodium(I)].

The versatile synthetic precursor methanolate-bridged title rhodium complex, [Rh(2)(CH(3)O)(2)(C(12)H(6)F(4))(2)] or [Rh(µ-OCH(3))(tfbb)](2) [tfbb = tetrafluorobenzobarrelene or 3,4,5,6-tetrafluorotricyclo[6.2.2.0(2,7)]dodeca-2(7),3,5,9,11-pentaene], has been structurally characterized. The asymmetric unit contains half a molecule that can be expanded via a twofold axis. The title compound has been shown to be a dinuclear rhodium complex where each metal centre is coordinated by two O atoms from two bridging methanolate groups and by the olefinic bonds of a tfbb ligand. Comparison of the bite angles of tfbb, norbornadiene (nbd) and cyclooctadiene (cod) olefins in their η(4)-coordination to rhodium reveals similarities between the tfbb and nbd ligands, which are much more rigid than cod. The short distance found between the distorted square-planar metal centres [2.8351 (4) Å] has been related to the syn conformation of the folded core `RhORhO' ring.

Phase I/II trial of sequential treatment of nab-paclitaxel in combination with gemcitabine followed by modified FOLFOX chemotherapy in patients with untreated metastatic exocrine pancreatic cancer: Phase I results.

BACKGROUND: Although occasioned through different mechanisms, the potential neurotoxicity and also haematological toxicity of nab-paclitaxel and oxaliplatin-based chemotherapy regimen were studied in this trial, which aimed to determine the maximum-tolerated dose (MTD) and to evaluate safety and efficacy of the combination in a sequential regimen of nab-paclitaxel, gemcitabine (GEM) and modified FOLFOX (mFOLFOX) in untreated patients with metastatic pancreatic ductal adenocarcinoma (PDAC). MATERIALS AND METHODS: Treatment consisted of nab-paclitaxel (125/100 mg/m2) plus GEM (1000/800 mg/m2) on days 1, 8 and 15, followed by mFOLFOX (oxaliplatin [85/75/65 mg/m2], 5-FU bolus [400/300/200 mg/m2], 5-FU infusion [2400/2000/1600 mg/m2]) on day 28, of a 42-day cycle. Patients were enrolled at the highest dose level with a subsequent 3 + 3 dose de-escalation plan. RESULTS: Eleven patients (median age = 61, 64% with performance status [PS] = 1) were eligible. All patients received the highest dose level. No de-escalation was needed. A dose-limiting toxicity was reported, an upper gastrointestinal haemorrhage. The MTD was nab-paclitaxel 125 mg/m2, GEM 1000 mg/m2, oxaliplatin 85 mg/m2, 5-FU bolus 400 mg/m2 and 5-FU infusion 2400 mg/m2. Common all-grade toxicities were neutropenia (73%), anaemia (55%), thrombocytopenia (55%) and asthenia (55%). Other relevant toxicities were paraesthesia (46%), nausea (36%), dysesthesia (27%) and pyrexia (27%). Objective response rate was 50% and disease control rate was 80%. CONCLUSIONS: The regimen of nab-paclitaxel plus GEM followed by mFOLFOX showed favourable safety and tolerability profiles with significant anti-tumor activity. More data are being achieved in a randomised phase II trial, to confirm efficacy rates and dismiss long-term neurotoxicity concerns regarding the sequencing of nab-paclitaxel and oxaliplatin.

Correction to: A Phase II Study Evaluating Combined Neoadjuvant Cetuximab and Chemotherapy Followed by Chemoradiotherapy and Concomitant Cetuximab in Locoregional Oesophageal Cancer Patients.

Errors were subsequently identified in the article and the following corrections should be noted.

A phase II Study Evaluating Combined Neoadjuvant Cetuximab and Chemotherapy Followed by Chemoradiotherapy and Concomitant Cetuximab in Locoregional Oesophageal Cancer Patients.

BACKGROUND: Pre-operative chemoradiotherapy using a 5-fluorouracil (5-FU)/cisplatin backbone is widely used to improve surgical outcomes in locoregional oesophageal cancer patients, despite a non-negligible failure rate. OBJECTIVE: We evaluated intensification of this approach to improve patient outcomes by adding cetuximab to induction 5-FU/cisplatin/docetaxel (TPF) and to chemoradiotherapy in a phase II study. PATIENTS AND METHODS: Between November 2006 and April 2009, 50 patients with stage II-IVa squamous cell carcinoma (SCC) or adenocarcinoma of the oesophagus or gastro-oesophageal junction initiated three TPF/cetuximab cycles. Six weeks later, patients with response or stabilisation initiated 6 weeks of cisplatin/cetuximab/radiotherapy, followed by surgery. The primary objective was the clinical complete response (cCR) rate after induction therapy plus chemoradiotherapy in intent-to-treat patients. RESULTS: Thirty-eight patients were evaluable after chemoradiotherapy, 84% of whom showed disease control. Six patients (12%) achieved a cCR, with a 54% overall response rate. Twenty-seven patients underwent surgery, 11 of whom (22%; nine SCC, two adenocarcinoma) had a pathological CR (41%). Fifteen patients were alive after a median follow-up of 23.2 months. Median progression-free survival was 12.2 months (95% confidence interval [CI] 1.7-22.8). Median overall survival was 23.4 months (95% CI 12.2-36.6) and was significantly longer among the 22 patients with complete resection than in the five patients without (42.1 vs. 24.9 months; p = 0.02, hazard ratio: 3.6, 95% CI 1.1-11.6). The toxicity profile was acceptable. CONCLUSIONS: Neoadjuvant cetuximab/TPF followed by chemoradiotherapy in locoregional oesophageal carcinoma patients is feasible and offers a modest response rate in this trial. The results of combining trimodality neoadjuvant treatment with cetuximab are consistent with the literature. Registration: The study is registered at ClinicalTrials.gov (NCT00733889).

Reactivity of the parent amido complexes of iridium with olefins: C-NH2 bond formation versus C-H activation.

Herein we report on the different chemical reactivity displayed by two mononuclear terminal amido compounds depending on the nature of the coordinated diene. Hence, treatment of amido-bridged iridium complexes [{Ir(µ-NH2)(tfbb)}3] (1; tfbb = tetrafluorobenzobarrelene) with dppp (dppp = bis(diphenylphosphane)propane) leads to the rupture of the amido bridges forming the mononuclear terminal amido compound [Ir(NH2)(dppp)(tfbb)] (3) in the first stage. On changing the reaction conditions, the formation of a C-NH2 bond between the amido moiety and the coordinated diene is observed and a new dinuclear complex [{Ir(1,2-η2-4-κ-C12H8F4N)(dppp)}2(µ-dppp)] (4) has been isolated. On the contrary, the diiridium amido-bridged complex [{Ir(µ-NH2)(cod)}2] (2; cod = 1,5-cyclooctadiene) in the presence of dppb (dppb = bis(diphenylphosphane)butane) allows the isolation of a mononuclear complex [Ir(1,2,3-η3-6-κ-C8H10)H(dppb)] (5), as a consequence of the extrusion of ammonia. The monitoring of the reaction of 2 with dppb (and dppp) allowed us to detect terminal amido complexes [Ir(NH2)(P-P)(cod)] (P-P = dppb (6), dppp (7)) in solution, as confirmed by an X-ray analysis of 7. Complex 7 was observed to evolve into hydrido species 5 at room temperature. DFT studies showed that C-H bond activation occurs through the deprotonation of one methylene fragment of the cod ligand by the highly basic terminal amido moiety instead of C-H oxidative addition to the Ir(i) center.

Rational design of protamine nanocapsules as antigen delivery carriers.

Current challenges in global immunization indicate the demand for new delivery strategies, which could be applied to the development of new vaccines against emerging diseases, as well as to improve safety and efficacy of currently existing vaccine formulations. Here, we report a novel antigen nanocarrier consisting of an oily core and a protamine shell, further stabilized with pegylated surfactants. These nanocarriers, named protamine nanocapsules, were rationally designed to promote the intracellular delivery of antigens to immunocompetent cells and to trigger an efficient and long-lasting immune response. Protamine nanocapsules have nanometric size, positive zeta potential and high association capacity for H1N1 influenza hemagglutinin, a protein that was used here as a model antigen. The new formulation shows an attractive stability profile both, as an aqueous suspension or a freeze-dried powder formulation. In vitro studies showed that protamine nanocapsules were efficiently internalized by macrophages without eliciting significant toxicity. In vivo studies indicate that antigen-loaded nanocapsules trigger immune responses comparable to those achieved with alum, even when using significantly lower antigen doses, thus indicating their adjuvant properties. These promising in vivo data, alongside with their versatility for the loading of different antigens and oily immunomodulators and their excellent stability profile, make these nanocapsules a promising platform for the delivery of antigens. CHEMICAL COMPOUNDS: Protamine sulphate (PubChem SID: 7849283), Sodium Cholate (PubChem CID: 23668194), Miglyol (PubChem CID: 53471835), α tocopherol (PubChem CID: 14985), Tween® 20(PubChem CID: 443314), Tween® 80(PubChem CID: 5281955), TPGS (PubChem CID: 71406).

P-H activation of secondary phosphanes on a parent amido diiridium complex.

Selected secondary phosphanes (H-PR2; R = Ph, Cy, (i)Pr) smoothly react with a parent amido-bridged diiridium cyclooctadiene complex affording mixed amido/(bis)phosphido dinuclear species. A careful investigation of the reaction profile, carried out by experimental and theoretical tools, revealed that, after an initial amido/phosphido exchange, at low temperatures a second molecule of secondary phosphane adds to the dinuclear system through an oxidative addition process leading to a hydrido amido/bis(phosphido) mixed-valence complex [Ir(III)/Ir(I)]. These species rearrange above -10 °C into the most stable isomer that arises from a migration of the hydrido moiety to one of the =CH fragments of a coordinated cod molecule, a transformation facilitated by the formation of an intermetallic bond. Further heating of these species reductively eliminates ammonia affording bis(phosphido)-metal-metal bonded complexes.

Endosomal maturation, Rab7 GTPase and phosphoinositides in African swine fever virus entry.

Here we analyzed the dependence of African swine fever virus (ASFV) infection on the integrity of the endosomal pathway. Using confocal immunofluorescence with antibodies against viral capsid proteins, we found colocalization of incoming viral particles with early endosomes (EE) during the first minutes of infection. Conversely, viral capsid protein was not detected in acidic late endosomal compartments, multivesicular bodies (MVBs), late endosomes (LEs) or lysosomes (LY). Using an antibody against a viral inner core protein, we found colocalization of viral cores with late compartments from 30 to 60 minutes postinfection. The absence of capsid protein staining in LEs and LYs suggested that virus desencapsidation would take place at the acid pH of these organelles. In fact, inhibitors of intraluminal acidification of endosomes caused retention of viral capsid staining virions in Rab7 expressing endosomes and more importantly, severely impaired subsequent viral protein production. Endosomal acidification in the first hour after virus entry was essential for successful infection but not thereafter. In addition, altering the balance of phosphoinositides (PIs) which are responsible of the maintenance of the endocytic pathway impaired ASFV infection. Early infection steps were dependent on the production of phosphatidylinositol 3-phosphate (PtdIns3P) which is involved in EE maturation and multivesicular body (MVB) biogenesis and on the interconversion of PtdIns3P to phosphatidylinositol 3, 5-biphosphate (PtdIns(3,5)P(2)). Likewise, GTPase Rab7 activity should remain intact, as well as processes related to LE compartment physiology, which are crucial during early infection. Our data demonstrate that the EE and LE compartments and the integrity of the endosomal maturation pathway orchestrated by Rab proteins and PIs play a central role during early stages of ASFV infection.