Guinea fowl eggshell structural analysis at different scales reveals how organic matrix induces microstructural shifts that enhance its mechanical properties

Guinea fowl eggshells have an unusual structural arrangement that is different from that of most birds, consisting of two distinct layers with different microstructures. This bilayered organization, and distinct microstructural characteristics, provides it with exceptional mechanical properties. The inner layer, constituting about one third of the eggshell thickness, contains columnar calcite crystal units arranged vertically as in most bird shells. However, the thicker outer layer has a more complex microstructural arrangement formed by a switch to smaller calcite domains with diffuse/interlocking boundaries, partly resembling the interfaces seen in mollusk shell nacre. The switching process that leads to this remarkable second-layer microstructure is unknown. Our results indicate that the microstructural switching is triggered by changes in the inter- and intracrystalline organic matrix. During production of the outer microcrystalline layer in the later stages of eggshell formation, the interactions of organic matter with mineral induce an accumulation of defects that increase crystal mosaicity, instill anisotropic lattice distortions in the calcite structure, interrupt epitaxial growth, reduce crystallite size, and induce nucleation events which increase crystal misorientation. These structural changes, together with the transition between the layers and each layer having different microstructures, enhance the overall mechanical strength of the Guinea fowl eggshell. Additionally, our findings provide new insights into how biogenic calcite growth may be regulated to impart unique functional properties. STATEMENT OF SIGNIFICANCE: Avian eggshells are mineralized to protect the embryo and to provide calcium for embryonic chick skeletal development. Their thickness, structure and mechanical properties have evolved to resist external forces throughout brooding, yet ultimately allow them to crack open during chick hatching. One particular eggshell, that of the Guinea fowl, has structural features very different from other galliform birds - it is bilayered, with an inner columnar mineral structure (like in most birds), but it also has an outer layer with a complex microstructure which contributes to its superior mechanical properties. This work provides novel and new fundamental information about the processes and mechanisms that control and change crystal growth during the switch to microcrystalline domains when the second outer layer forms.

CRISPR-Cas9 In Vivo Gene Editing of KLKB1 for Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a rare genetic disease that leads to severe and unpredictable swelling attacks. NTLA-2002 is an in vivo gene-editing therapy based on clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9. NTLA-2002 targets the gene encoding kallikrein B1 (KLKB1), with the goal of lifelong control of angioedema attacks after a single dose.

METHODS

In this phase 1 dose-escalation portion of a combined phase 1-2 trial of NTLA-2002 in adults with hereditary angioedema, we administered NTLA-2002 at a single dose of 25 mg, 50 mg, or 75 mg. The primary end points were the safety and side-effect profile of NTLA-2002 therapy. Secondary and exploratory end points included pharmacokinetics, pharmacodynamics, and clinical efficacy determined on the basis of investigator-confirmed angioedema attacks.

RESULTS

Three patients received 25 mg of NTLA-2002, four received 50 mg, and three received 75 mg. At all dose levels, the most common adverse events were infusion-related reactions and fatigue. No dose-limiting toxic effects, serious adverse events, grade 3 or higher adverse events, or clinically important laboratory findings were observed after the administration of NTLA-2002. Dose-dependent reductions in the total plasma kallikrein protein level were observed between baseline and the latest assessment, with a mean percentage change of -67% in the 25-mg group, -84% in the 50-mg group, and -95% in the 75-mg group. The mean percentage change in the number of angioedema attacks per month between baseline and weeks 1 through 16 (primary observation period) was -91% in the 25-mg group, -97% in the 50-mg group, and -80% in the 75-mg group. Among all the patients, the mean percentage change in the number of angioedema attacks per month from baseline through the latest assessment was -95%.

CONCLUSIONS

In this small study, a single dose of NTLA-2002 led to robust, dose-dependent, and durable reductions in total plasma kallikrein levels, and no severe adverse events were observed. In exploratory analyses, reductions in the number of angioedema attacks per month were observed at all dose levels. (Funded by Intellia Therapeutics; ClinicalTrials.gov number, NCT05120830.).

CRISPR-Cas9 In Vivo Gene Editing for Transthyretin Amyloidosis

BACKGROUND

Transthyretin amyloidosis, also called ATTR amyloidosis, is a life-threatening disease characterized by progressive accumulation of misfolded transthyretin (TTR) protein in tissues, predominantly the nerves and heart. NTLA-2001 is an in vivo gene-editing therapeutic agent that is designed to treat ATTR amyloidosis by reducing the concentration of TTR in serum. It is based on the clustered regularly interspaced short palindromic repeats and associated Cas9 endonuclease (CRISPR-Cas9) system and comprises a lipid nanoparticle encapsulating messenger RNA for Cas9 protein and a single guide RNA targeting TTR.

METHODS

After conducting preclinical in vitro and in vivo studies, we evaluated the safety and pharmacodynamic effects of single escalating doses of NTLA-2001 in six patients with hereditary ATTR amyloidosis with polyneuropathy, three in each of the two initial dose groups (0.1 mg per kilogram and 0.3 mg per kilogram), within an ongoing phase 1 clinical study.

RESULTS

Preclinical studies showed durable knockout of TTR after a single dose. Serial assessments of safety during the first 28 days after infusion in patients revealed few adverse events, and those that did occur were mild in grade. Dose-dependent pharmacodynamic effects were observed. At day 28, the mean reduction from baseline in serum TTR protein concentration was 52% (range, 47 to 56) in the group that received a dose of 0.1 mg per kilogram and was 87% (range, 80 to 96) in the group that received a dose of 0.3 mg per kilogram.

CONCLUSIONS

In a small group of patients with hereditary ATTR amyloidosis with polyneuropathy, administration of NTLA-2001 was associated with only mild adverse events and led to decreases in serum TTR protein concentrations through targeted knockout of TTR. (Funded by Intellia Therapeutics and Regeneron Pharmaceuticals; ClinicalTrials.gov number, NCT04601051.).

Biological stenciling of mineralization in the skeleton: Local enzymatic removal of inhibitors in the extracellular matrix

Biomineralization is remarkably diverse and provides myriad functions across many organismal systems. Biomineralization processes typically produce hardened, hierarchically organized structures usually having nanostructured mineral assemblies that are formed through inorganic-organic (usually protein) interactions. Calcium‑carbonate biomineral predominates in structures of small invertebrate organisms abundant in marine environments, particularly in shells (remarkably it is also found in the inner ear otoconia of vertebrates), whereas calcium-phosphate biomineral predominates in the skeletons and dentitions of both marine and terrestrial vertebrates, including humans. Reconciliation of the interplay between organic moieties and inorganic crystals in bones and teeth is a cornerstone of biomineralization research. Key molecular determinants of skeletal and dental mineralization have been identified in health and disease, and in pathologic ectopic calcification, ranging from small molecules such as pyrophosphate, to small membrane-bounded matrix vesicles shed from cells, and to noncollagenous extracellular matrix proteins such as osteopontin and their derived bioactive peptides. Beyond partly knowing the regulatory role of the direct actions of inhibitors on vertebrate mineralization, more recently the importance of their enzymatic removal from the extracellular matrix has become increasingly understood. Great progress has been made in deciphering the relationship between mineralization inhibitors and the enzymes that degrade them, and how adverse changes in this physiologic pathway (such as gene mutations causing disease) result in mineralization defects. Two examples of this are rare skeletal diseases having osteomalacia/odontomalacia (soft bones and teeth) - namely hypophosphatasia (HPP) and X-linked hypophosphatemia (XLH) - where inactivating mutations occur in the gene for the enzymes tissue-nonspecific alkaline phosphatase (TNAP, TNSALP, ALPL) and phosphate-regulating endopeptidase homolog X-linked (PHEX), respectively. Here, we review and provide a concept for how existing and new information now comes together to describe the dual nature of regulation of mineralization - through systemic mineral ion homeostasis involving circulating factors, coupled with molecular determinants operating at the local level in the extracellular matrix. For the local mineralization events in the extracellular matrix, we present a focused concept in skeletal mineralization biology called the Stenciling Principle - a principle (building upon seminal work by Neuman and Fleisch) describing how the action of enzymes to remove tissue-resident inhibitors defines with precision the location and progression of mineralization.

Breast Conservation After Neoadjuvant Chemotherapy for Triple-Negative Breast Cancer: Surgical Results From the BrighTNess Randomized Clinical Trial

Importance

Neoadjuvant systemic therapy (NST) is often administered to enable breast-conserving therapy (BCT) in stages II to III breast cancer.

Objectives

To prospectively evaluate the role of NST in conversion from BCT ineligibility to BCT eligibility and to assess the association of response to NST, germline BRCA (gBRCA) status, and region of treatment with surgical choice in women with triple-negative breast cancer (TNBC).

Design, Setting, and Participants

This prespecified secondary analysis of a multicentered, phase 3, double-blind, randomized clinical trial (BrighTNess) enrolled 634 eligible women across 145 centers in 15 countries in North America, Europe, and Asia. Women with operable, clinical stages II to III TNBC who underwent gBRCA mutation testing before initiating NST were eligible to participate. Data were collected from April 1, 2014, to December 8, 2016. This preplanned analysis was performed from January 5, 2018, to October 28, 2019.

Interventions

Study participants were randomized to receive 12 weeks of weekly paclitaxel alone or with the addition of carboplatin and/or veliparib, followed by 4 cycles of doxorubicin hydrochloride and cyclophosphamide.

Main Outcomes and Measures

Surgeons assessed BCT candidacy by clinical and radiographic criteria before and after NST. Surgical choices and whether BCT eligibility was associated with the likelihood of pathologic complete response were then analyzed.

Results

Among the 634 randomized patients (median age, 51 [range, 22-78] years), pre- and post-NST assessments were available for 604 patients. Of 141 patients deemed BCT ineligible at baseline, 75 (53.2%) converted to BCT eligible. Overall, 342 (68.1%) of 502 patients deemed BCT eligible after NST underwent BCT, including 42 (56.0%) of the 75 who converted to BCT eligible. Patients treated in Europe and Asia were more likely to undergo BCT (odds ratio, 2.66; 95% CI, 1.84-3.84) compared with those treated in North America. Among patients without gBRCA mutation undergoing mastectomy, those treated in North America were more likely to undergo contralateral prophylactic mastectomy (57 of 81 [70.4%] vs 6 of 30 [20.0%]; P < .001). Rates of pathologic complete response were similar between patients deemed BCT eligible at baseline and those who were BCT ineligible but converted to BCT eligibility after NST (55.3 [235 of 425] vs 49.3% [37 of 75]; P = .38).

Conclusions and Relevance

This prospective analysis of NST and BCT eligibility in TNBC demonstrates a conversion from BCT ineligibility to BCT eligibility of 53.2%. Lower BCT rates among eligible patients and higher bilateral mastectomy rates among patients without gBRCA mutation in North America merit investigation.

Trial Registration

ClinicalTrials.gov identifier: NCT02032277.

Abstract 1150: Acute myeloid leukemia human/mouse co-clinical trial feasibility study optimized in human transgenic IL-3/GMCSF NOD/Shi-scid-IL2rγnull mice

Acute myeloid leukemia (AML) co-clinical modeling has been optimized with peripheral blood mononuclear cells (PBMCs) collected from low volume (14 mL) patient samples to establish an algorithm for efficiently co-clinically modeling AML patients. Methods: PBMCs were ficoll gradient purified and viably cryopreserved. Intrahepatic (i.h.) inoculation of AML PBMCs in neonate NOD/Shi-scid-IL2rγnull (NOG) mice and intravenous (i.v.) inoculation in both juvenile NOG mice and juvenile human transgenic IL-3/GMCSF NOD/Shi-scid-IL2rγnull mice (NOG-EXL) were evaluated. Bone marrow (BM) aspirates, splenocytes and PBMCs from mice were evaluated by fluorescence-activated cell sorting (FACS) at 12 weeks post AML inoculation for engraftment as determined by % ratio of human CD33+ cells to total CD45+ cells (human + murine cells). Humerus bones from inoculated animals were also evaluated by human CD33 immunohistochemistry (IHC). Results: Cells from 2/6 AML patient samples (CTG-2224 and CTG-2357) successfully engrafted into neonate mice. Animals were dosed with vehicle, cytarabine, ABBV-075 (clinical trial-staged BET family bromodomain (BD) inhibitor), or ABBV-744 (a preclinical BDII selective inhibitor) and evaluated for tumor burden six weeks post drug treatment initiation. ABBV-075 and ABBV-744 treated animals had lower tumor burden in the CTG-2224 model, 17% (p&lt;0.05) and 4% (p&lt;0.01); respectively. Similar trends, albeit at lower engraftment (10%), were observed for both models in spleen and blood compartments. In an effort to improve engraftment efficiency NOG-EXL mice were evaluated as hosts for engraftment with a patient PBMC sample (CTG-2357) and compared with juvenile NOG mice. Efficiency in the number of mice engrafted (8/8 vs. 3/7) and the extent of BM engraftment (51% vs. 14%) following a 0.5 X 106 PBMC inoculation was improved with the NOG-EXL mice. Furthermore, a patient inoculum (CTG-2241) that had previously shown no engraftment in juvenile NOG mice exhibited a 92% take rate with 93% BM tumor burden in NOG-EXL mice. Discussion: Prior advances in AML modeling show engraftment in IL2rγnul mouse models including i.h. and i.v. inoculation of BM clinical isolates in neonate NSG mice, i.v. inoculation of leukapheresis clinical isolates in juvenile NSG and NSG-SGM3 mice, and i.v. inoculation of BM aspirates in MISTRG mice. Each approach has limitations in terms of tedious neonate mice husbandry, ease of clinical sample collection with respect to clinical patient compliance, and mouse strain availability. Here we examined the feasibility of efficiently engrafting AML regardless of mutation or clinical stage from 14 ml PBMC samples. Results showed that i.v. inoculation of AML clinical samples in juvenile NOG-EXL mice was advantageous. This research is prerequisite for conducting translational co-clinical in vivo pharmacology studies for ABBV-075.

Citation Format: Neal C. Goodwin, Daniel H. Albert, Angela M. Davies, Jenny Rowe, Gerold Feuer, Michael Boyiadzis, Kathleen A. Dorritie, Maria Mancini, Regina Gandour-Edwards, Warren M. Kati, Mark D. McKee, Keith F. McDaniel, David J. Frost. Acute myeloid leukemia human/mouse co-clinical trial feasibility study optimized in human transgenic IL-3/GMCSF NOD/Shi-scid-IL2rγnull mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1150.

Bone toughness at the molecular scale: A model for fracture toughness using crosslinked osteopontin on synthetic and biogenic mineral substrates

The most prominent structural components in bone are collagen and mineral. However, bone additionally contains a substantial amount of noncollagenous proteins (most notably of the SIBLING protein family), some of which may act as cohesive/adhesive "binders" for the composite hybrid collagen/mineral scaffolding, whether in the bulk phase of bone, or at its interfaces. One such noncollagenous protein - osteopontin (OPN) - appears to be critical to the deformability and fracture toughness of bone. In the present study, we used a reconstructed synthetic mineral-OPN-mineral interface, and a biogenic (natural tooth dentin) mineral/collagen-OPN-mineral/collagen interface, to measure the fracture toughness of OPN on mineralized substrates. We used this system to test the hypothesis that OPN crosslinking by the enzyme tissue transglutaminase 2 (TG2) that is found in bone enhances interfacial adhesion to increase the fracture toughness of bone. For this, we prepared double-cantilever beam substrates of synthetic pure hydroxyapatite mineral, and of narwhal dentin, and directly apposed them to one another under different intervening OPN/crosslinking conditions, and fracture toughness was tested using a miniaturized loading stage. The work-of-fracture of the OPN interface was measured for different OPN formulations (monomer vs. polymer), crosslinking states, and substrate composition. Noncrosslinked OPN provided negligible adhesion on pure hydroxyapatite, whereas OPN crosslinking (by the chemical crosslinker glutaraldehyde, and TG2 enzyme) provided strong interfacial adhesion for both hydroxyapatite and dentin using monomeric and polymeric OPN. Pre-coating of the substrate beams with monomeric OPN further improved the adhesive performance of the samples, likely by allowing effective binding of this nascent OPN form to mineral/matrix components, with this pre-attachment providing a protein layer for additional crosslinking between the substrates.

Phase I combination study of the PARP inhibitor veliparib plus carboplatin and gemcitabine in patients with advanced ovarian cancer and other solid malignancies

OBJECTIVE

Determine the maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of veliparib combined with carboplatin and gemcitabine in patients with advanced ovarian cancer and other nonhematologic malignancies.

METHODS

In this phase I study, patients with metastatic or unresectable solid tumors and ≤2 prior chemotherapy regimens received veliparib combined with carboplatin area under the curve (AUC) 4 on day 1 and gemcitabine 800mg/m² on days 1 and 8 of a 21-day cycle for maximum 10cycles, followed by optional veliparib maintenance therapy. Veliparib dosing commenced twice-daily (BID) continuously on day 1 of cycle 2; granulocyte colony-stimulating factor was permitted. Dose escalation used a Bayesian continual reassessment method. Safety, tolerability, and efficacy were evaluated.

RESULTS

Seventy-five patients were enrolled (ovarian cancer, n=54; breast cancer, n=12). Thirty-six patients with ovarian cancer (67%) had known germline BRCA mutations. Most common treatment-related adverse events (TRAEs; ≥60%) were thrombocytopenia, neutropenia, nausea, and anemia. Most common grade 3/4 TRAEs (≥40%) were neutropenia and thrombocytopenia. Dose-limiting toxicities were thrombocytopenia and neutropenia. The MTD/RP2D was established at veliparib 250mg with carboplatin AUC 4 plus gemcitabine 800mg/m². Responses were observed in 69% of patients with BRCA-deficient ovarian cancer (45% partial, 24% complete responses). Five patients remained on veliparib (80-310mg BID) for >34cycles.

CONCLUSIONS

Veliparib plus carboplatin/gemcitabine is tolerated, with a safety profile similar to carboplatin and gemcitabine alone. Combination therapy demonstrated promising preliminary antitumor activity in platinum-sensitive ovarian cancer patients with germline BRCA mutations. Trial registration ID: NCT01063816.

Defective Mineralization in X-Linked Hypophosphatemia Dental Pulp Cell Cultures

X-linked hypophosphatemia (XLH) is a skeletal disease caused by inactivating mutations in the PHEX gene. Mutated or absent PHEX protein/enzyme leads to a decreased serum phosphate level, which cause mineralization defects in the skeleton and teeth (osteomalacia/odontomalacia). It is not yet altogether clear whether these manifestations are caused solely by insufficient circulating phosphate availability for mineralization or also by a direct, local intrinsic effect caused by impaired PHEX activity. Here, we evaluated the local role of PHEX in a 3-dimensional model of extracellular matrix (ECM) mineralization. Dense collagen hydrogels were seeded either with human dental pulp cells from patients with characterized PHEX mutations or with sex- and age-matched healthy controls and cultured up to 24 d using osteogenic medium with standard phosphate concentration. Calcium quantification, micro-computed tomography, and histology with von Kossa staining for mineral showed significantly lower mineralization in XLH cell-seeded scaffolds, using nonparametric statistical tests. While apatitic mineralization was observed along collagen fibrils by electron microscopy in both groups, Raman microspectrometry indicated that XLH cells harboring the PHEX mutation produced less mineralized scaffolds having impaired mineral quality with less carbonate substitution and lower crystallinity. In the XLH cultures, immunoblotting revealed more abundant osteopontin (OPN), dentin matrix protein 1 (DMP1), and matrix extracellular phosphoglycoprotein (MEPE) than controls, as well as the presence of fragments of these proteins not found in controls, suggesting a role for PHEX in SIBLING protein degradation. Immunohistochemistry revealed altered OPN and DMP1 associated with an increased alkaline phosphatase staining in the XLH cultures. These results are consistent with impaired PHEX activity having local ECM effects in XLH. Future treatments for XLH should target both systemic and local manifestations.

Safety, pharmacokinetics, and pharmacodynamics of oral omaveloxolone (RTA 408), a synthetic triterpenoid, in a first-in-human trial of patients with advanced solid tumors

Background

Omaveloxolone is a semisynthetic oleanane triterpenoid that potently activates Nrf2 with subsequent antioxidant function. We conducted a first-in-human Phase I clinical trial (NCT02029729) with the primary objectives to determine the appropriate dose for Phase II studies, characterize pharmacokinetic and pharmacodynamic parameters, and assess antitumor activity.

Methods

Omaveloxolone was administered orally once daily continuously in a 28-day cycle for patients with stage 4 relapsed/refractory melanoma or non-small cell lung cancer. An accelerated titration design was employed until a grade 2-related adverse event (AE) occurred. A standard 3+3 dose escalation was employed. Single-dose and steady-state plasma pharmacokinetics of the drug were characterized. Downstream Nrf2 activation was assessed in peripheral blood mononuclear cells by quantification of target gene mRNA expression.

Results

Omaveloxolone was tested at four dose levels up to 15 mg given orally once daily. No dose-limiting toxicities were detected, and the maximum tolerated dose was not determined. All drug-related AEs were either grade 1 or 2 in severity, and none required clinical action. The most common drug-related AEs were elevated alkaline phosphatase (18%) and anemia (18%). No drug interruptions or reductions were required. Omaveloxolone was rapidly absorbed and exhibited proportional increases in exposure across dose levels. With some exceptions, an overall trend toward time-dependent and dose-dependent activation of Nrf2 antioxidant genes was observed. No confirmed radiologic responses were seen, although one lung cancer subject did have stable disease exceeding 1 year.

Conclusions

Omaveloxolone has favorable tolerability at biologically active doses, although this trial had a small sample size which limits definitive conclusions. These findings support further investigation of omaveloxolone in cancer.

Breast conservation after neoadjuvant chemotherapy for triple-negative breast cancer: Surgical results from an international randomized trial (BrighTNess)

514

Background: Neoadjuvant systemic therapy (NST) increases the frequency of breast-conserving therapy (BCT) in stage II-III breast cancer, but there is little data on how often it converts patients (pts) from BCT-ineligible (BCT-I) to BCT-eligible (BCT-E) and on the impact of other factors on surgical choices. We collected surgical assessment and management data from an international randomized trial of NST in triple-negative breast cancer (TNBC). Methods: Women with operable TNBC were randomized to veliparib (V) with carboplatin (C) and paclitaxel (P), placebo with C and P or placebo with P followed by doxorubicin and cyclophosphamide. The surgeons assessed BCT candidacy by clinico-radiographic criteria before and after NST; surgical management was at surgeon and patient discretion. We assessed interactions between BCT eligibility pre- and post-NST, germline BRCA mutation ( gBRCA) status, continent of treatment and achievement of pathologic complete response(pCR) and percentage of pts who underwent BCT versus mastectomy. Results: Pre- and post-NST surgical assessments were available for 604 pts who underwent surgery. BCT rates are listed in the Table. The BCT rate was 68% among pts deemed BCT-E after NST. pCR rates were identical between BCT-E pts who chose BCT (55%) vs. mastectomy (53%). Of 141 pts deemed BCT-I at baseline, 75 (53%) converted to BCT-E but only 42 (56%) of these opted for BCT. pCR rates were 49% in BCT-E converts vs. 36% in those remained BCT-I. gBRCA pts (n = 84) were less likely to choose BCT even if they were BCT-E. Pts treated in North America (NA) were less likely to choose BCT (55% vs. 80% for Europe and Asia P<0.0001) even among non- gBRCA considered BCT-E post-NST (61% vs. 85% P<0.0001). Conclusions: This largest prospective analysis of the impact of NST in TNBC demonstrates a conversion rate from BCT-I to BCT-E of 53%. BCT rates were lower in pts with gBRCA; the much higher mastectomy rate among BCT-E pts in NA merits investigation. Clinical trial information: NCT02032277. [Table: see text]

Pharmaco-kinetics/dynamics (PK/PD) evaluation and individual patient cross-over studies with growth trajectory assessment to adaptively develop ilorasertib

2563

Background: We evaluated PK/PD of the AURK B/VEGFR2 inhibitor ilorasertib. To detect activity in CDKN2A-deficient tumors, we measured changes-in-tumor-burden by CT-volume before, during, and after discontinuation of therapy. Methods: Study 1: open-label, dose-escalation, phase 1 in 58 patients (pts) with advanced solid tumors. Arms I, II, and III assigned: 23 pts (10–180 mg oral QD), 28 pts (40–340 mg oral BID), and 7 pts (8–32 mg i.v. QD), to ilorasertib monotherapy Days 1, 8, and 15 every 28 days. We evaluated PK/PD for validated biomarkers: change-in-diastolic blood pressure (ΔDBP), change-in-plasma [PlGF] (ΔPlGF), and change-in phosphorylated histone H3 (Δ%pHH3) in skin biopsies. Study 2: open-label trial, of 10 solid tumor pts with CLIA-lab-detected CDKN2A disruption. Pts received ilorasertib 250 mg oral BID on same schedule. On CT images collected prior to screening, and ~ study days -7, 49, and 98 individual lesion volumes were determined by central lab semi-automated segmentation algorithms on DICOM files. Pts who tolerated ilorasertib with RECIST-stable disease at day 98 discontinued ilorasertib for 42 days and underwent re-imaging before restarting ilorasertib. Results: Study 1: the DLTs and frequent adverse events reflected VEGFR2 inhibition. PK/PD analysis showed peak VEGFR2 inhibition on ΔDBP and ΔPlGF at lower systemic concentrations than for peak AURKB-inhibition detected with Δ%pHH3. Two pts in Arm II had partial response; one had homozygous deletion of CDKN2Aby FISH. Pre-clinically the CDKN2A-deficient cell lines (OVCAR5, MDA MB 231, A549) were among the most ilorasertib-sensitive. At time of submission, Study II enrolled 10 pts, with 5 evaluable for longitudinal tumor burden assessments. Three pts had sustained negative growth trajectories after ilorasertib therapy; one of these had positive growth after cessation of treatment but restabilization of disease after restarting ilorasertib. Conclusions: The development plan adapted to the in-human PK/PD assessment. We prospectively conducted individual change-in-tumor burden cross-over studies to assess clinically the sensitivity of CDKN2A-deficient tumors. Clinical trial information: NCT02540876 and NCT01110486.

Phase 3 study evaluating efficacy and safety of veliparib (V) plus carboplatin (Cb) or Cb in combination with standard neoadjuvant chemotherapy (NAC) in patients (pts) with early stage triple-negative breast cancer (TNBC)

520

Background: Clinical studies suggest that TNBC is sensitive to DNA-damaging agents, including Cb. V is a potent PARP inhibitor that may enhance the antitumor activity of such agents. We present primary response data from a phase 3 randomized, placebo-controlled study (NCT02032277) evaluating the addition of V + Cb or Cb to neoadjuvant paclitaxel (P) followed by doxorubicin + cyclophosphamide (AC). Methods: Pts with histologically confirmed, invasive TNBC (T2–T4 N0–2 or T1 N1–2) amenable to surgical resection were randomized 2:1:1 to (Arm A) P 80 mg/m2 weekly + Cb AUC 6 mg/mL/min q3 weeks + V 50 mg PO BID; (Arm B) P + Cb + PO placebo; or (Arm C) P + IV placebo + PO placebo, for 12 weeks followed by AC (60 mg/m2 or 600 mg/m2 q2 or 3 weeks) × 4. Primary endpoint was pathologic complete response (pCR) in breast and nodes with > 80% power at 2-sided α of 0.05 using pair-wise comparisons for A vs B and A vs C to detect significant treatment effects using Χ2 test; secondary endpoint was rate of conversion to eligibility for breast conservation surgery (BCS). Adverse events (AEs) were assessed with NCI CTCAE V4.0. Results: Six hundred thirty-four pts (median age 50 years; range 22–79) were randomized to Arms A (n = 316), B (n = 160), or C (n = 158). Baseline characteristics were well balanced. No pCR difference was observed between Arms A and B (53.2% vs 57.5% p = 0.36), but pCR in Arm A was higher than Arm C (53.2% vs 31.0% p < 0.001). In non-prespecified analysis, pCR in Arm B was also higher than Arm C (57.5% vs 31.0% p < 0.001). Among pts ineligible for BCS at screening (n = 141), 62% were eligible after NAC in Arm A vs 44% each in Arms B (p = 0.13) and C (p = 0.14). Grade 3–4 AEs (Arms A/B/C, 86%/85%/45%) and serious AEs (30%/27%/14%) neutropenia, thrombocytopenia, anemia, nausea, and vomiting were increased with the addition of Cb; V did not impact toxicity. Median cycles of NAC were not reduced with V + Cb + P or Cb + P vs P. Conclusions: Addition of V to neoadjuvant Cb + P followed by AC did not increase pCR rate in breast and nodes in stage II–III TNBC, while addition of V + Cb or Cb alone to P followed by AC did. Cb (+/– V) increased toxicity but did not impact delivery of NAC. Clinical trial information: NCT02032277.

Tolerability of veliparib (V) in combination with carboplatin (C)/paclitaxel (P): Based chemoradiotherapy (CRT) in subjects with stage III non-small cell lung cancer (NSCLC)

8546

Background: CRT is a standard for patients with Stage III NSCLC. V is a potent, orally bioavailable PARP1/2 inhibitor that can delay DNA repair following chemotherapy or radiation induced damage. A Phase 2 study indicated favorable efficacy of V vs placebo when added to C/P in advanced NSCLC (Ramalingam et al. Clin Cancer Res. 2016). Based on these results, a Phase 1/2 trial was initiated to study the safety and efficacy of V/C/P-based CRT in the treatment of Stage III NSCLC. Methods: Subjects without prior NSCLC therapy suitable for definitive CRT received V plus C AUC 2 + P 45 mg/m2 weekly + 60 Gy over 6-9 weeks. V was escalated from 60 mg BID to a maximum planned dose based on prior studies of 240 mg BID via 3+3 design with allowed over-enrollment followed by consolidation therapy of V 120 mg BID + C AUC 6 + P 200 mg/m2 for up to two 21-day cycles. Results: Thirty-one subjects (median age 64; 10 male) have been enrolled to date into dosing cohorts at 60 mg (7), 80 mg (9), 120 mg (7) and 200 mg (8). PK of V was dose proportional. CRT or V required dose reduction for 0 or 1 subject, respectively. Four (13%) subjects discontinued study during CRT. No DLTs have been observed and an MTD has not yet been identified. The most common any grade AEs were fatigue (16), esophagitis (15), nausea (13), neutropenia (12), thrombocytopenia (12), constipation (10) and decreased appetite (10). 21 SAEs were observed including 8 with reasonable attribution to V but outside the DLT window including G3/4 febrile neutropenia (2), G3 dehydration (1), G3 vomiting (1), G3 radiation esophagitis (1), G3 esophageal stricture (1), G3 intractable N/V (1) and G5 sepsis during consolidation (1). Of 21 subjects evaluable for tumor assessment, best response was CR (1), PR (11), SD (6), and PD (3). Conclusions: V/C/P-based CRT followed by V/C/P consolidation therapy is a tractable regimen for the treatment of Stage III NSCLC. A randomized placebo-controlled Phase 2 extension of this study is planned. Clinical trial information: NCT02412371.

Total hip arthroplasty following failure of core decompression and tantalum rod implantation

AIMS

One method of femoral head preservation following avascular necrosis (AVN) is core decompression and insertion of a tantalum rod. However, there may be a high failure rate associated with this procedure. The purpose of this study was to document the clinical and radiological outcomes following total hip arthroplasty (THA) subsequent to failed tantalum rod insertion.

PATIENTS AND METHODS

A total of 37 failed tantalum rods requiring total hip arthroplasty were identified from a prospective database. There were 21 hips in 21 patients (12 men and nine women, mean age 37 years, 18 to 53) meeting minimum two year clinical and radiographic follow-up whose THAs were carried out between November 2002 and April 2013 (mean time between tantalum rod implantation and conversion to a THA was 26 months, 6 to 72). These were matched by age and gender to individuals (12 men, nine women, mean age 40 years, 18 to 58) receiving THA for AVN without prior tantalum rod insertion.

RESULTS

There were no functional outcome differences between the two groups. Tantalum residue was identified on all post-operative radiographs in the tantalum group. Linear wear rates were comparable between groups with no evidence of catastrophic wear in either group.

CONCLUSION

In the short term, tantalum rod implantation does not demonstrate an adverse effect on subsequent total joint replacement surgery. There is however, a high rate of retained tantalum debris on post-operative radiographs and thus there is an unknown risk of accelerated articular wear necessitating longer term study. Cite this article: Bone Joint J 2016;98-B:1175-9.

Transglutaminase Crosslinking of SIBLING Proteins in Teeth

Transglutaminase 2 (TG2), a protein-crosslinking enzyme, participates in extracellular matrix maturation and cell adhesion in cartilage and bone. We hypothesized that TG2 has similar roles in teeth. A TG activity assay and immunoblotting of rat tooth extracts showed TG activity and the presence of high-molecular-weight forms of the SIBLING (Small Integrin-Binding LIgand N-linked Glycoprotein) proteins: dentin matrix protein 1 (DMP1), dentin phosphoprotein (DPP), and bone sialoprotein (BSP). DMP1 and BSP, each containing both glutamine and lysine residues critical for crosslink formation, readily formed polymers in vitro when incubated with TG2. The ability of glutamine-lacking DPP to form polymers in vitro and in vivo demonstrates that it could act as a lysine donor for crosslinking, potentially having protein crosslinking partner(s) in teeth. Consistent with a role in cell adhesion, the TG2 isoform was co-localized by immunohistochemistry with its substrates at cell-matrix adhesion sites, including along odontoblast tubules (DMP1 and DPP), in the pericellular matrix of cementocytes (DMP1), and in predentin (BSP).

Craniofacial and Dental Defects in the Col1a1Jrt/+ Mouse Model of Osteogenesis Imperfecta

Certain mutations in the COL1A1 and COL1A2 genes produce clinical symptoms of both osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS) that include abnormal craniofacial growth, dental malocclusion, and dentinogenesis imperfecta. A mouse model (Col1a1(Jrt)/+) was recently developed that had a skeletal phenotype and other features consistent with moderate-to-severe OI and also with EDS. The craniofacial phenotype of 4- and 20-wk-old Col1a1(Jrt)/+ mice and wild-type littermates was assessed by micro-computed tomography (µCT) and morphometry. Teeth and the periodontal ligament compartment were analyzed by µCT, light microscopy/histomorphometry, and electron microscopy. Over time, at 20 wk, Col1a1(Jrt)/+ mice developed smaller heads, a shortened anterior cranial base, class III occlusion, and a mandibular side shift with shorter morphology in the masticatory region (maxilla and mandible). Col1a1(Jrt)/+ mice also had changes in the periodontal compartment and abnormalities in the dentin matrix and mineralization. These findings validate Col1a1(Jrt)/+ mice as a model for OI and EDS in humans.

Phase 1 dose escalation trial of ilorasertib, a dual Aurora/VEGF receptor kinase inhibitor, in patients with hematologic malignancies

BACKGROUND

Ilorasertib (ABT-348) is a novel inhibitor of Aurora kinase, vascular endothelial growth factor (VEGF) and platelet-derived growth factor receptors, and the Src families of tyrosine kinases. Ilorasertib alone or in combination with azacitidine demonstrated activity in preclinical models in various hematological malignancies, indicating that pan-Aurora kinase and multiple kinase inhibition may have preferential antileukemic activity. This phase 1 trial determined the safety, pharmacokinetics, and preliminary antitumor activity of ilorasertib alone or combined with azacitidine in advanced hematologic malignancies.

PATIENTS AND METHODS

Fifty-two patients (median age, 67 years; 35 % with >4 prior regimens) with acute myelogenous leukaemia (AML; n = 38), myelodysplastic syndrome (n = 12), or chronic myelomonocytic leukaemia (n = 2) received 3 or 6 doses of ilorasertib per 28-day cycle and were assigned to arm A (once-weekly oral), B (twice-weekly oral), C (once-weekly oral plus azacitidine), or D (once-weekly intravenous) treatment.

RESULTS

Maximum tolerated doses were not determined; the recommended phase 2 oral monotherapy doses were 540 mg once weekly and 480 mg twice weekly. The most common grade 3/4 adverse events were hypertension (28.8 %), hypokalemia (15.4 %), anemia (13.5 %), and hypophosphatemia (11.5 %). Oral ilorasertib pharmacokinetics appeared dose proportional, with a 15-hour half-life and no interaction with azacitidine. Ilorasertib inhibited biomarkers for Aurora kinase and VEGF receptors, and demonstrated clinical responses in 3 AML patients.

CONCLUSIONS

Ilorasertib exhibited acceptable safety and pharmacokinetics at or below the recommended phase 2 dose, displayed evidence of dual Aurora kinase and VEGF receptor kinase inhibition, and activity in AML.

Randomized phase II study of carboplatin and paclitaxel with either linifanib or placebo for advanced nonsquamous non-small-cell lung cancer

PURPOSE

Linifanib, a potent, selective inhibitor of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptors, has single-agent activity in non-small-cell lung cancer (NSCLC). We evaluated linifanib with carboplatin and paclitaxel as first-line therapy of advanced nonsquamous NSCLC.

PATIENTS AND METHODS

Patients with stage IIIB/IV nonsquamous NSCLC were randomly assigned to 3-week cycles of carboplatin (area under the curve 6) and paclitaxel (200 mg/m(2)) with daily placebo (arm A), linifanib 7.5 mg (arm B), or linifanib 12.5 mg (arm C). The primary end point was progression-free survival (PFS); secondary efficacy end points included overall survival (OS) and objective response rate.

RESULTS

One hundred thirty-eight patients were randomly assigned (median age, 61 years; 57% men; 84% smokers). Median PFS times were 5.4 months (95% CI, 4.2 to 5.7 months) in arm A (n = 47), 8.3 months (95% CI, 4.2 to 10.8 months) in arm B (n = 44), and 7.3 months (95% CI, 4.6 to 10.8 months) in arm C (n = 47). Hazard ratios (HRs) for PFS were 0.51 for arm B versus A (P = .022) and 0.64 for arm C versus A (P = .118). Median OS times were 11.3, 11.4, and 13.0 months in arms A, B, and C, respectively. HRs for OS were 1.08 for arm B versus A (P = .779) and 0.88 for arm C versus A (P = .650). Both linifanib doses were associated with increased toxicity, including a higher incidence of adverse events known to be associated with VEGF/PDGF inhibition. Baseline plasma carcinoembryonic antigen/cytokeratin 19 fragments biomarker signature was associated with PFS improvement and a trend toward OS improvement with linifanib 12.5 mg.

CONCLUSION

Addition of linifanib to chemotherapy significantly improved PFS (arm B), with a modest trend for survival benefit (arm C) and increased toxicity reflective of known VEGF/PDGF inhibitory effects.

Extracellular matrix mineralization in murine MC3T3-E1 osteoblast cultures: an ultrastructural, compositional and comparative analysis with mouse bone

Bone cell culture systems are essential tools for the study of the molecular mechanisms regulating extracellular matrix mineralization. MC3T3-E1 osteoblast cell cultures are the most commonly used in vitro model of bone matrix mineralization. Despite the widespread use of this cell line to study biomineralization, there is as yet no systematic characterization of the mineral phase produced in these cultures. Here we provide a comprehensive, multi-technique biophysical characterization of this cell culture mineral and extracellular matrix, and compare it to mouse bone and synthetic apatite mineral standards, to determine the suitability of MC3T3-E1 cultures for biomineralization studies. Elemental compositional analysis by energy-dispersive X-ray spectroscopy (EDS) showed calcium and phosphorus, and trace amounts of sodium and magnesium, in both biological samples. X-ray diffraction (XRD) on resin-embedded intact cultures demonstrated that similar to 1-month-old mouse bone, apatite crystals grew with preferential orientations along the (100), (101) and (111) mineral planes indicative of guided biogenic growth as opposed to dystrophic calcification. XRD of crystals isolated from the cultures revealed that the mineral phase was poorly crystalline hydroxyapatite with 10 to 20nm-sized nanocrystallites. Consistent with the XRD observations, electron diffraction patterns indicated that culture mineral had low crystallinity typical of biological apatites. Fourier-transform infrared spectroscopy (FTIR) confirmed apatitic carbonate and phosphate within the biological samples. With all techniques utilized, cell culture mineral and mouse bone mineral were remarkably similar. Scanning (SEM) and transmission (TEM) electron microscopy showed that the cultures had a dense fibrillar collagen matrix with small, 100nm-sized, collagen fibril-associated mineralization foci which coalesced to form larger mineral aggregates, and where mineralized sites showed the accumulation of the mineral-binding protein osteopontin. Light microscopy, confocal microscopy and three-dimensional reconstructions showed that some cells had dendritic processes and became embedded within the mineral in an osteocyte-like manner. In conclusion, we have documented characteristics of the mineral and matrix phases of MC3T3-E1 osteoblast cultures, and have determined that the structural and compositional properties of the mineral are highly similar to that of mouse bone.

Linifanib versus Sorafenib in patients with advanced hepatocellular carcinoma: results of a randomized phase III trial

PURPOSE

This open-label phase III trial evaluated efficacy and tolerability of linifanib versus sorafenib in patients with advanced hepatocellular carcinoma (HCC) without prior systemic therapy.

PATIENTS AND METHODS

Patients were randomly assigned in a 1:1 ratio to linifanib 17.5 mg once daily or sorafenib 400 mg twice daily. Patients were stratified by region (Outside Asia, Japan, and rest of Asia), Eastern Cooperative Oncology Group performance score (ECOG PS; 0 or 1), vascular invasion or extrahepatic spread (yes or no), and hepatitis B virus (HBV) infection (yes or no). The primary end point of the study was overall survival (OS). Secondary end points were time to progression (TTP) and objective response rate (ORR) per RECIST v1.1.

RESULTS

We randomly assigned 1,035 patients (median age, 60 years; Asian, 66.6%; ECOG PS 0, 65.2%; HBV, 49.1%; vascular invasion or extrahepatic spread, 70.1%). Median OS was 9.1 months on the linifanib arm (95% CI, 8.1 to 10.2) and 9.8 months on the sorafenib arm (95% CI, 8.3 to 11.0; hazard ratio [HR], 1.046; 95% CI, 0.896 to 1.221). For prespecified stratification subgroups, OS HRs ranged from 0.793 to 1.119 and the 95% CI contained 1.0. Median TTP was 5.4 months on the linifanib arm (95% CI, 4.2 to 5.6) and 4.0 months on the sorafenib arm (95% CI, 2.8 to 4.2; HR, 0.759; 95% CI, 0.643 to 0.895; P = .001). Best response rate was 13.0% on the linifanib arm versus 6.9% on the sorafenib arm. Grade 3/4 adverse events (AEs); serious AEs; and AEs leading to discontinuation, dose interruption, and reduction were more frequent with linifanib (all P < .001).

CONCLUSION

Linifanib and sorafenib had similar OS in advanced HCC. Predefined superiority and noninferiority OS boundaries were not met for linifanib and the study failed to meet the primary end point. TTP and ORR favored linifanib; safety results favored sorafenib.

Randomized phase II open-label study of mFOLFOX6 in combination with linifanib or bevacizumab for metastatic colorectal cancer

BACKGROUND

Although CRC is the third most commonly diagnosed cancer in the United States, second-line CRC treatment is limited. In this trial we examined the efficacy and safety of linifanib, an oral, potent, selective tyrosine kinase inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptor families, with mFOLFOX6, compared with bevacizumab and mFOLFOX6, in previously treated metastatic CRC.

PATIENTS AND METHODS

One hundred forty-eight patients with advanced CRC previously treated with fluoropyrimidine or irinotecan received bevacizumab (10 mg/kg, intravenous), low-dose linifanib (7.5 mg), or high-dose linifanib (12.5 mg), with mFOLFOX6. The primary end point was progression-free survival (PFS). Secondary objectives included overall survival (OS), objective response rate (ORR), and safety.

RESULTS

No statistically significant differences in PFS occurred between bevacizumab and linifanib doses (low, hazard ratio [HR], 1.453 [95% confidence interval [CI], 0.830-2.539]; high, HR, 1.257 [95% CI, 0.672-2.351]). Median OS values were similar for bevacizumab and high-dose linifanib (bevacizumab, 16.5 months [95% CI, 13.0-not available]; high-dose linifanib, 16.4 months [95% CI, 11.9-21.7]; low-dose linifanib, 12.0 months [95% CI, 10.1-13.0]). ORRs were similar (bevacizumab, 34.7% [95% CI, 21.7-49.6]; low-dose linifanib, 24.0% [95% CI, 13.1-38.2]; high-dose linifanib, 22.4% [95% CI, 11.8-36.6]). Median cycles of 5-fluorouracil were reduced in the linifanib arms, versus the bevacizumab arm. Grade 3/4 adverse event occurrences were more frequent with linifanib. Palmar-plantar erythrodysesthesia, hypothyroidism, and thrombocytopenia were more common with high-dose linifanib than bevacizumab.

CONCLUSION

Combining linifanib with mFOLFOX6 as a second-line treatment for metastatic CRC did not improve PFS, radiographic findings, or duration of response versus bevacizumab and mFOLFOX6.

A phase 1 study of linifanib in combination with carboplatin/paclitaxel as first-line treatment of Japanese patients with advanced or metastatic non-small cell lung cancer (NSCLC)

INTRODUCTION

Linifanib is a potent, orally active, and selective inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptor kinase activities with clinical efficacy in non-small cell lung cancer (NSCLC). This phase 1 dose-escalation study evaluated the pharmacokinetics, safety, and efficacy of linifanib in combination with carboplatin/paclitaxel in Japanese patients with advanced NSCLC.

METHODS

Carboplatin (AUC = 6 mg/mL/min) and paclitaxel (200 mg/m²) were administered on day 1 of each 21-day cycle up to a maximum of six cycles. Oral linifanib (7.5 mg) was given to six patients once daily throughout all cycles and escalated to 12.5 mg/day in a second cohort of six patients.

RESULTS

Twelve patients received at least one dose of linifanib. The most common adverse events were hematologic and consistent with expected toxicities with carboplatin/paclitaxel. With 12.5 mg linifanib, grade 3/4 neutropenia, leukopenia, and thrombocytopenia occurred in 100, 83, and 83 % of patients, respectively. Dose-limiting grade 4 thrombocytopenia occurred in one patient at each dose level. Linifanib pharmacokinetics was similar to that in non-Japanese patients. At 12.5 mg, linifanib Cmax was 0.32 μg/mL and AUC₂₄ was 4.29 μg h/mL. Linifanib Cmax occurred at 2-3 h with both doses and when given alone or in combination with carboplatin/paclitaxel. Exposure to linifanib appeared to be increased by carboplatin/paclitaxel, and exposure to paclitaxel appeared to be increased by linifanib. Partial responses were observed in nine patients.

CONCLUSIONS

Linifanib added to carboplatin/paclitaxel is well tolerated in Japanese patients with advanced/metastatic NSCLC. The recommended dose of linifanib with carboplatin/paclitaxel is 12.5 mg, same as for US patients.

Compounded PHOSPHO1/ALPL deficiencies reduce dentin mineralization

Phosphatases are involved in bone and tooth mineralization, but their mechanisms of action are not completely understood. Tissue-nonspecific alkaline phosphatase (TNAP, ALPL) regulates inhibitory extracellular pyrophosphate through its pyrophosphatase activity to control mineral propagation in the matrix; mice without TNAP lack acellular cementum, and have mineralization defects in dentin, enamel, and bone. PHOSPHO1 is a phosphatase found within membrane-bounded matrix vesicles in mineralized tissues, and double ablation of Alpl and Phospho1 in mice leads to a complete absence of skeletal mineralization. Here, we describe mineralization abnormalities in the teeth of Phospho1(-/-) mice, and in compound knockout mice lacking Phospho1 and one allele of Alpl (Phospho1(-/-);Alpl(+/-) ). In wild-type mice, PHOSPHO1 and TNAP co-localized to odontoblasts at early stages of dentinogenesis, coincident with the early mineralization of mantle dentin. In Phospho1 knockout mice, radiography, micro-computed tomography, histology, and transmission electron microscopy all demonstrated mineralization abnormalities of incisor dentin, with the most remarkable findings being reduced overall mineralization coincident with decreased matrix vesicle mineralization in the Phospho1(-/-) mice, and the almost complete absence of matrix vesicles in the Phospho1(-/-);Alpl(+/-) mice, whose incisors showed a further reduction in mineralization. Results from this study support prominent non-redundant roles for both PHOSPHO1 and TNAP in dentin mineralization.

Latissimus dorsi tendon transfer for irreparable tears of the rotator cuff: An anatomical study to assess the neurovascular hazards and ways of improving tendon excursion

Latissimus dorsi tendon transfer (LDTT) is technically challenging. In order to clarify the local structural anatomy, we undertook a morphometric study using six complete cadavers (12 shoulders). Measurements were made from the tendon to the nearby neurovascular structures with the arm in two positions: flexed and internally rotated, and adducted in neutral rotation. The tendon was then transferred and measurements were taken from the edge of the tendon to a reference point on the humeral head in order to assess the effect of a novel two-stage release on the excursion of the tendon. With the shoulder flexed and internally rotated, the mean distances between the superior tendon edge and the radial nerve, brachial artery, axillary nerve and posterior circumflex artery were 30 mm (26 to 34), 28 mm (17 to 39), 21 mm (12 to 28) and 15 mm (10 to 21), respectively. The mean distance between the inferior tendon edge and the radial nerve, brachial artery and profunda brachii artery was 18 mm (8 to 27), 22 mm (15 to 32) and 14 mm (7 to 21), respectively. Moving the arm to a neutral position reduced these distances. A mean of 15 mm (8 to 21) was gained from a standard soft-tissue release, and 32 mm (20 to 45) from an extensile release. These figures help to define further the structural anatomy of this region and the potential for transfer of the latissimus dorsi tendon.

Phase I study of ABT-888 in combination with carboplatin and gemcitabine in subjects with advanced solid tumors

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Background: Veliparib (V) is an oral inhibitor of poly(ADP-ribose) polymerases (PARP)-1 and -2, which are essential for base excision repair of ssDNA breaks. BRCA deficient tumors are more sensitive to PARP inhibitors when used as monotherapy or in combination with DNA-damaging agents. The objectives of this study were to determine the maximum tolerated dose (MTD), pharmacokinetic interactions, and safety/tolerability profile of V in combination with carboplatin (C) and gemcitabine (G). Methods: Eligibility criteria included patients (pts) with metastatic or unresectable solid tumors for which C/G was a treatment option. During the study, eligibility was amended to limit prior chemotherapy regimens to ≤ 2. C AUC 4 /G 800 mg/m2was given intravenously on Day 1 and G given on Day 8 of 21 day cycles. To assess tolerability of C/G prior to V, V was started in Cycle 2. When C/G was stopped, pts could stay on monotherapy V until progression. Dose-escalation used a Bayesian continual reassessment method. Results: 59 pts (51 female, median age 52) were enrolled. The most common tumor types were ovarian (n=39) and breast (n=10). Germline BRCA mutations were known in 24 ovarian pts. 58 pts had prior chemotherapy (1-6 regimens, median 2), and 51 had prior platinum. Grade 3/4 AEs in >10% of pts were neutropenia, thrombocytopenia, anemia, and leukopenia. Dose limiting toxicities were thrombocytopenia (n=3) and neutropenia at V 310 mg twice daily (BID) and thrombocytopenia at 250 mg BID. Other frequent AEs were nausea, constipation, and fatigue. Preliminary results showed co-administration of V did not affect C or G pharmacokinetics. Treatment cycles (range, median) were 1-28, 5 for V; 2-10, 5 for C; and 2-10, 4 for G. Day 8 G was stopped in some pts to improve tolerability. 28 pts stayed on monotherapy V (1-23 cycles). Partial and complete responses were seen in 11 and 2 pts. Response rates were 47% (8/17) in known BCRA deficient ovarian, 25% (3/12) in other ovarian, and 13% (2/15) in other evaluable pts. Conclusions: V combined with C and G was tolerated with a safety profile similar to C and G alone. The MTD was V 250 mg BID, C AUC 4.0, G 800 mg/m2. Promising anti-tumor activity was observed in BRCA deficient ovarian pts. Clinical trial information: NCT01063816.

Mineralization of dense collagen hydrogel scaffolds by human pulp cells

While advances in biomineralization have been made in recent years, unanswered questions persist on bone- and tooth-cell differentiation, on outside-in signaling from the extracellular matrix, and on the link between protein expression and mineral deposition. In the present study, we validate the use of a bioengineered three-dimensional (3D) dense collagen hydrogel scaffold as a cell-culture model to explore these questions. Dental pulp progenitor/stem cells from human exfoliated deciduous teeth (SHEDs) were seeded into an extracellular matrix-like collagen gel whose fibrillar density was increased through plastic compression. SHED viability, morphology, and metabolic activity, as well as scaffold mineralization, were investigated over 24 days in culture. Additionally, measurements of alkaline phosphatase enzymatic activity, together with immunoblotting for mineralized tissue cell markers ALPL (tissue-non-specific alkaline phosphatase), DMP1 (dentin matrix protein 1), and OPN (osteopontin), demonstrated osteo/odontogenic cell differentiation in the dense collagen scaffolds coincident with mineralization. Analyses of the mineral phase by electron microscopy, including electron diffraction and energy-dispersive x-ray spectroscopy, combined with Fourier-transform infrared spectroscopy and biochemical analyses, were consistent with the formation of apatitic mineral that was frequently aligned along collagen fibrils. In conclusion, use of a 3D dense collagen scaffold promoted SHED osteo/odontogenic cell differentiation and mineralization.

Phase III trial of linifanib versus sorafenib in patients with advanced hepatocellular carcinoma (HCC)

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Background: Linifanib (ABT-869; Lin) is a potent and selective inhibitor of the vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptor tyrosine kinase families. In a phase II trial in patients (pts) with advanced HCC, Lin showed clinical activity (objective response rate [ORR] 10.5% in Child-Pugh A [CPA] pts). This open-label, global phase 3 trial evaluated Lin versus sorafenib (Sor) as first-line therapy in pts with advanced CPA HCC (NCT01009593). Methods: Pts were randomized 1:1 to Lin 17.5 mg QD or Sor 400 mg BID and stratified by region (non-Asia/Japan/rest of Asia), ECOG performance status (0/1), vascular invasion or extrahepatic spread (yes/no) and HBV infection (yes/no). The primary efficacy endpoint was overall survival (OS); both non-inferiority (margin 1.0491) and superiority hypotheses were to be tested. Secondary efficacy endpoints included time to progression (TTP) and ORR, using RECIST v1.1. AE severity was graded using NCI-CTCAE v4.0. Results: 1035 pts (median age 60 y, 68% Asian, 65% ECOG 0, 49% HBV, 70% vascular invasion or extrahepatic spread) were randomized at 149 sites in 26 countries. Hazard ratio (HR) for OS was 1.046 (95% CI: 0.896, 1.221). Median OS (95% CI) was 9.1 months (m) (8.1, 10.2) on Lin and 9.8 m (8.3, 11.0) on Sor. For all pre-specifed subgroup analyses, OS HRs ranged from 0.793-1.119, and the 95% CI contained 1.0. TTP HR was 0.759 (95% CI: 0.643, 0.895; p=0.001) favoring Lin. Median TTP (95% CI) was 5.4 m (4.2, 5.6) on Lin and 4.0 m (2.8. 4.2) on Sor. ORR was 13.0% on Lin and 6.9% on Sor. Grade 3/4 AEs, serious AEs and AEs leading to discontinuations, dose interruptions and reductions were more frequent on Lin versus Sor (all p<0.001). Conclusions: Lin and Sor resulted in similar OS in advanced HCC. Predefined superiority and non-inferiority OS boundaries were not met for Lin. Secondary endpoints (TTP and ORR) favored Lin while safety results favored Sor. Clinical trial information: NCT01009593.

Tooth root dentin mineralization defects in a mouse model of hypophosphatasia

Tissue-nonspecific alkaline phosphatase (TNAP) is expressed in mineralizing tissues and functions to reduce pyrophosphate (PP(i) ), a potent inhibitor of mineralization. Loss of TNAP function causes hypophosphatasia (HPP), a heritable disorder marked by increased PP(i) , resulting in rickets and osteomalacia. Tooth root cementum defects are well described in both HPP patients and in Alpl(-/-) mice, a model for infantile HPP. In Alpl(-/-) mice, dentin mineralization is specifically delayed in the root; however, reports from human HPP patients are variable and inconsistent regarding dentin defects. In the current study, we aimed to define the molecular basis for changes in dentinogenesis observed in Alpl(-/-) mice. TNAP was found to be highly expressed by mature odontoblasts, and Alpl(-/-) molar and incisor roots featured defective dentin mineralization, ranging from a mild delay to severely disturbed root dentinogenesis. Lack of mantle dentin mineralization was associated with disordered and dysmorphic odontoblasts having disrupted expression of marker genes osteocalcin and dentin sialophosphoprotein. The formation of, initiation of mineralization within, and rupture of matrix vesicles in Alpl(-/-) dentin matrix was not affected. Osteopontin (OPN), an inhibitor of mineralization that contributes to the skeletal pathology in Alpl(-/-) mice, was present in the generally unmineralized Alpl(-/-) mantle dentin at ruptured mineralizing matrix vesicles, as detected by immunohistochemistry and by immunogold labeling. However, ablating the OPN-encoding Spp1 gene in Alpl(-/-) mice was insufficient to rescue the dentin mineralization defect. Administration of bioengineered mineral-targeting human TNAP (ENB-0040) to Alpl(-/-) mice corrected defective dentin mineralization in the molar roots. These studies reveal that TNAP participates in root dentin formation and confirm that reduction of PP(i) during dentinogenesis is necessary for odontoblast differentiation, dentin matrix secretion, and mineralization. Furthermore, these results elucidate developmental mechanisms underlying dentin pathology in HPP patients, and begin to explain the reported variability in the dentin/pulp complex pathology in these patients.

Cohesive behavior of soft biological adhesives: experiments and modeling

Extracellular proteins play a key role in generating and maintaining cohesion and adhesion in biological tissues. These "natural glues" are involved in vital biological processes such as blood clotting, wound healing and maintaining the structural integrity of tissues. Macromolecular assemblies of proteins can be functionally stabilized in a variety of ways in situ that include ionic interactions as well as covalent crosslinking to form protein networks that can extend both within and between tissues. Within tissues, myriad cohesive forces are required to preserve tissue integrity and function, as are additional appropriate adhesive forces at interfaces both within and between tissues of differing composition. While the mechanics of some key structural adhesive proteins have been characterized in tensile experiments at both the macroscopic and single protein levels, the fracture toughness of thin proteinaceous interfaces has never been directly measured. Here, we describe a novel and simple approach to measure the cohesive behavior and toughness of thin layers of proteinaceous adhesives. The test is based on the standard double-cantilever beam test used for engineering adhesives, which was adapted to take into account the high compliance of the interface compared with the beams. This new "rigid double-cantilever beam" method enables stable crack propagation through an interfacial protein layer, and provides a direct way to measure its full traction-separation curve. The method does not require any assumption of the shape of the cohesive law, and the results provide abundant information contributing to understanding the structural, chemical and molecular mechanisms acting in biological adhesion. As an example, results are presented using this method for thin films of fibrin-a protein involved in blood clotting and used clinically as a tissue bio-adhesive after surgery-with the effects of calcium and crosslinking by Factor XIII being examined. Finally, a simple model is proposed, demonstrating how a bell-shaped cohesive law forms during the failure of the fibrin interface based on an eight-chain model whose structure degrades and changes configuration with stress.

Randomized phase II open-label study of mFOLFOX6 in combination with linifanib or bevacizumab for metastatic colorectal cancer

3532

Background: Linifanib is a potent and selective inhibitor of VEGF/PDGF receptors. This trial assessed the efficacy and safety of mFOLFOX6 in combination with linifanib or bevacizumab as second-line treatment for metastatic colorectal cancer (mCRC). Methods: Patients (pts) with measurable mCRC refractory to 1 prior regimen and ECOG PS 0–1, stratified by prior bevacizumab treatment and radiotherapy, were randomized to receive mFOLFOX6 with bevacizumab 10 mg/kg on day (d) 1 of 14-d cycle (Arm A), mFOLFOX6 with daily linifanib 7.5 mg (Arm B), or mFOLFOX6 with daily linifanib 12.5 mg (Arm C). The primary endpoint was progression-free survival (PFS). Severity of adverse events (AEs) was graded using NCI-CTCAE v3.0. Results: 148 pts were randomized at 45 sites in 14 countries. 32 pts (21.6%) had received prior bevacizumab. PFS and response data are shown below (Table). Median survival (OS) was not reached at median follow up 7.6 months. Palmar-plantar erythrodysesthesia (PPE) was the only Grade 3/4 AE significantly higher on linifanib (high dose, 16.3%) vs. bevacizumab (0%). Rate of any Grade 3+ AE was significantly higher on linifanib vs. bevacizumab.Hypertension rates were 41.7% (Arm A), 40.0% (Arm B), and 36.7% (Arm C). AEs dose-related to linifanib were constipation, proctalgia, stomatitis, fatigue, weight decrease, decreased appetite, and PPE. Conclusions: The addition of linifanib to mFOLFOX6, compared to mFOLFOX6 + bevacizumab, did not provide a PFS advantage for mCRC. OS results will be updated for conference presentation. [Table: see text]

Randomized phase II study of carboplatin and paclitaxel with either linifanib or placebo for advanced nonsquamous NSCLC

7512

Background: Linifanib is a potent and selective inhibitor of VEGF and PDGF receptors with modest single-agent activity in NSCLC. We evaluated the combination of linifanib with carboplatin (C) and paclitaxel (P) for first-line therapy of advanced non-squamous NSCLC. Methods: Patients (pts) with stage IIIB/IV, non-squamous NSCLC, stratified by ECOG PS and gender, were randomized to receive up to six 3-wk cycles of C (AUC 6 mg/ml/min) and P (200 mg/m2) with daily placebo (Arm A), linifanib 7.5 mg (Arm B), or linifanib 12.5 mg (Arm C). The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), 12 m survival rate, and objective response rate (ORR). Safety was assessed by NCI-CTCAE v3.0. Results: 138 pts were randomized at 37 sites in 6 countries. Baseline characteristics were: median age, 61 y; men, 57%; smoker, 84%. Efficacy results are shown in the table. Thrombocytopenia was the only Grade 3/4 AE significantly higher on linifanib (Arm B: 16.7%; Arm C: 29.8%) vs. placebo (2.1%). Other adverse events (AEs) related to the dose of linifanib were diarrhea, thrombocytopenia, hypertension, weight loss, palmar-plantar erythrodysaesthesia syndrome, and hypothyroidism. Analysis of samples for predictive biomarkers including serum VEGF and placental growth factor are underway. Conclusions: The addition of linifanib to chemotherapy was tolerable at the doses tested and resulted in a significant improvement in PFS, with a modest survival improvement for Arm C in first-line therapy of advanced non-squamous NSCLC. [Table: see text]

Association of baseline plasma biomarker signature with survival in advanced NSCLC patients on linifanib

e13583

Background: Linifanib is a potent and selective VEGF and PDGF receptor inhibitor that has activity in unselected, advanced NSCLC patients (pts) both as monotherapy in the relapsed setting and with carboplatin (C) and paclitaxel (P) in the first-line setting. A baseline plasma biomarker signature identifying NSCLC pts most sensitive to linifanib is needed. Methods: An exploratory retrospective analysis of four randomized clinical trials including linifanib or other treatments in relapsed NSCLC was conducted. Evaluable baseline plasma samples were obtained from 116 pts who received linifanib and 71 pts on other treatments. A signature combining established tumor markers (carcinoembryonic antigen [CEA] and fragments of cytokeratin 19 [CYFRA 21-1]) was derived using a sequential BATTing approach. The signature was then tested across a randomized trial of CP + placebo, linifanib 7.5 mg, or linifanib 12.5 mg in first-line advanced, non-squamous NSCLC. Results: In 2/3L NSCLC, the signature was associated with improvement in survival on linifanib monotherapy (HR=0.51 vs. signature negative; P=0.0017), but no improvement in survival on other treatments (P=0.87). In the first-line setting with CP, the signature was associated with significant PFS improvement with linifanib and a trend towards significant overall survival improvement at high dose (Table). Conclusions: A baseline plasma biomarker signature is associated with improved survival in advanced NSCLC patients on linifanib. Incorporation of this signature should be considered in any further investigation of linifanib in NSCLC. [Table: see text]

An open-label, phase 1 study evaluating safety, tolerability, and pharmacokinetics of linifanib (ABT-869) in Japanese patients with solid tumors

Purpose

This phase 1 study assessed the safety, tolerability, pharmacokinetics, and preliminary antitumor activity of linifanib in Japanese patients with advanced solid tumors.

Methods

Patients were assigned to one of four sequential cohorts (0.05, 0.10, 0.20, or 0.25 mg/kg) of oral, once-daily linifanib on a 21-day cycle. Adverse events (AEs) were assessed per common terminology criteria for adverse events v3.0; tumor responses were assessed by response evaluation criteria in solid tumors.

Results

Eighteen patients were enrolled. Eleven (61%) received ≥3 prior therapies. Dose-limiting toxicities were Grade 3 ALT increase (0.10 mg/kg linifanib) and Grade 1 T-wave inversion (0.25 mg/kg linifanib) requiring dose interruption for >7 days and discontinuation on day 29. The most common linifanib-related AE was hypertension. Other significant treatment-related AEs included proteinuria, fatigue, and palmar-plantar erythrodysaesthesia. Linifanib pharmacokinetics were dose-proportional across 0.10–0.25 mg/kg. Two patients (11.1%) had confirmed partial responses, 12 had a best response of stable disease (11 had stable disease for ≥12 weeks), and four patients were not evaluable due to incomplete data. Four patients (lung cancer, breast cancer, thymic cancer, sarcoma) have continued linifanib for ≥48 weeks (range, 48–96+ weeks).

Conclusion

Linifanib was well tolerated with promising preliminary clinical activity in Japanese patients. Later-phase global studies examining linifanib efficacy will include Japanese patients.

Enzyme replacement therapy prevents dental defects in a model of hypophosphatasia

Hypophosphatasia (HPP) occurs from loss-of-function mutation in the tissue-non-specific alkaline phosphatase (TNALP) gene, resulting in extracellular pyrophosphate accumulation that inhibits skeletal and dental mineralization. TNALP-null mice (Akp2(-/-)) phenocopy human infantile hypophosphatasia; they develop rickets at 1 week of age, and die before being weaned, having severe skeletal and dental hypomineralization and episodes of apnea and vitamin B(6)-responsive seizures. Delay and defects in dentin mineralization, together with a deficiency in acellular cementum, are characteristic. We report the prevention of these dental abnormalities in Akp2(-/-) mice receiving treatment from birth with daily injections of a mineral-targeting, human TNALP (sALP-FcD(10)). sALP-FcD(10) prevented hypomineralization of alveolar bone, dentin, and cementum as assessed by micro-computed tomography and histology. Osteopontin--a marker of acellular cementum--was immuno-localized along root surfaces, confirming that acellular cementum, typically missing or reduced in Akp2(-/-) mice, formed normally. Our findings provide insight concerning how acellular cementum is formed on tooth surfaces to effect periodontal ligament attachment to retain teeth in their osseous alveolar sockets. Furthermore, they provide evidence that this enzyme-replacement therapy, applied early in post-natal life--where the majority of tooth root development occurs, including acellular cementum formation--could prevent the accelerated tooth loss seen in individuals with HPP.

Melanoma-associated antigen expression in lymphangioleiomyomatosis renders tumor cells susceptible to cytotoxic T cells

The antibody HMB45 is used to diagnose lymphangioleiomyomatosis, a hyperproliferative disorder of lung smooth muscle cells with mutations in both alleles of either TSC1 or TSC2. A subset of these tumor cells expresses the melanoma-associated antigens gp100 and melanoma antigen recognized by T cells (MART-1). To explore the feasibility of targeting tumors in lymphangioleiomyomatosis by melanoma immunotherapy, we therefore assessed melanoma target antigen expression and existing immune infiltration of affected tissue compared with normal lung and melanoma as well as the susceptibility of cultured lymphangioleiomyomatosis cells to melanoma reactive cytotoxic T lymphocytes in vitro. Tumors expressed tyrosinase-related proteins 1 and 2 but not tyrosinase, in addition to gp100 and MART-1, and were densely infiltrated by macrophages, but not dendritic cells or T cell subsets. Although CD8(+) lymphocytes were sparse compared with melanoma, cells cultured from lymphangioleiomyomatosis tissue were susceptible to cytotoxic, gp100 reactive, and major histocompatibility complex class I restricted CD8(+) T cells in functional assays. Responder T cells selectively clustered and secreted interferon-gamma in response to HLA-matched melanocytes and cultured lymphangioleiomyomatosis cells. This reactivity exceeded that based on detectable gp100 expression; thus, tumor cells in lymphangioleiomyomatosis may process melanosomal antigens different from melanocytic cells. Therefore, boosting immune responses to gp100 in lymphangioleiomyomatosis may offer a highly desirable treatment option for this condition.