Single Equivalent Dose Research Articles

A double-blind, randomised cross-over study to evaluate the absorption of a commercially available Ginkgo biloba extract compared to the liposomal extract Ginkgosome

BackgroundGinkgo biloba extracts (GBE) have been used in traditional medicines for centuries. GBE has been shown to deliver protective effects against symptoms of age-related cognitive decline. Despite there being standardised extractions for GBE, there is still variability in the absorption and efficacy of different extracts. Following the development of a liposomal GBE (Ginkgosome™), the aim of this study is to investigate the absorption of the liposomal formulation compared to a comparator formulation of equal dose.MethodsThirteen healthy male and female volunteers completed this single equivalent dose, randomised, double-blind crossover study. Plasma concentrations were determined at baseline and at regular intervals over a 24-h period following ingestion of 120 mg of either a liposomal or comparator formulation. ResultsThe liposomal formulation was able to increase plasma concentration of ginkgolide B and C by 1.9 and 2.2-fold compared to the comparator formulation.ConclusionThe novel liposomal formulation is safe in humans and demonstrates superior absorption for the supply of GBE constituents compared to a comparator standardised formulation.

Abstract 1753: IKS014, a HER2-targeting antibody drug conjugate incorporating novel bioconjugation and tumor-selective linker technology with improved in vivo efficacy and tolerability

Abstract HER2 has long been a target of high interest for antibody and antibody drug conjugate (ADC) therapeutics due to its well-documented overexpression in breast, gastric and lung cancer. While trastuzumab and ado-trastuzumab emtansine (T-DM1) have become an integral part of treatment paradigms for HER2-positive cancer, the more recent approvals of the fam-trastuzumab deruxtecan (DS-8201) ADC and the Fc-engineered margetuximab antibody have highlighted the potential for continued improvement over existing HER2-targeting therapies. IKS014 is a HER2-directed ADC that incorporates site-directed conjugation and tumor-selective glucuronide-trigger linker technology to reduce systemic off-target toxicity while maximizing efficient intracellular lysosomal payload release, thus holding the promise of a wider therapeutic index. IKS014 was generated by site-specific conjugation via a proprietary beta-glucuronide linker to the microtubule agent MMAF with a drug-to-antibody ratio (DAR) 2. In vitro and in vivo activity was evaluated in HER2-positive preclinical models with varying HER2 expression levels in comparison to benchmark ADCs. Pharmacokinetics (PK) and tolerability studies were conducted in rodent and cynomolgus monkey. IKS014 conjugation resulted in a homogeneous ADC with defined DAR and good physio-chemical properties. In vitro, IKS014 demonstrated dose dependent specific cytotoxicity against Her2-positive cell lines. In JIMT-1 breast cancer xenografts with moderate HER2-expression (HER2 IHC 2+), IKS014 causes complete regressions at a single dose of 5 mg/kg and partial regressions at 1 mg/kg, while T-DM1 results in only tumor growth inhibition even at 15 mg/kg. Anti-tumor efficacy of IKS014 in NCI-N87 (HER2 3+) gastric xenografts is comparable to DS-8201 but superior to T-DM1 at equivalent single doses ranging from 1 to 5 mg/kg. In a HER2-positive patient-derived gastric cancer model (HER2 2+), IKS014 was highly active at 5mg/kg Q2W x2, while T-DM1 was inactive at the same dosing schedule. IKS014 demonstrated stable PK with a terminal half-life of 8.7 days in rat and 4.6 days in monkey, and DAR 2 was maintained for up to 4 weeks. In cynomolgus monkeys, IKS014 was tolerated at 12 mg/kg single dose and 5 mg/kg repeat dose without ocular or lung toxicity findings. IKS014 was highly efficacious against HER2-positive tumor xenografts in vivo, including models with moderate target expression, and compared favorably to clinically validated benchmark ADCs. This improved preclinical efficacy combined with stable PK and good tolerability profile warrants further development of this novel ADC for HER2-positive cancers. Citation Format: Jutta Deckert, Jenny Thirlway, Yun-Hee Park, Ho Young Song, Chul-Woong Chung, Xuesong Wang, Zhenshan Zhang, Robert J. Lutz. IKS014, a HER2-targeting antibody drug conjugate incorporating novel bioconjugation and tumor-selective linker technology with improved in vivo efficacy and tolerability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1753.

0411 Once-Nightly Sodium Oxybate Dose Titration and Tolerability: Interim Data From RESTORE

Abstract Introduction Extended-release, once-nightly sodium oxybate (ON-SXB; FT218) is under FDA review for the treatment of adults with narcolepsy. RESTORE, an ongoing, open-label extension/switch study (NCT04451668), evaluates long-term ON-SXB safety and tolerability. This interim analysis assessed dosing titration, tolerability, and study continuation. Methods RESTORE enrolls adults with narcolepsy in 1 of 3 groups: those with prior REST-ON participation but no current oxybate use (Group A), those who switched from twice-nightly oxybates (Group B), and oxybate-naïve patients (Group C). No patients rolled directly from REST-ON to RESTORE. Initial dose for Groups A/C was 4.5 g/night. Group B switched to ON-SXB from stable doses of twice-nightly oxybate to the nearest equivalent single dose. Investigators could increase or decrease dose by 1.5-g increments weekly as needed. Descriptive statistics were used to analyze dose titration and discontinuations. Results At an interim data cutoff date of November 14, 2021, 99 participants were enrolled and had received ≥1 dose of ON-SXB (not currently taking oxybate, n=24; switch, n=75). For Groups A/C, 5 (21%) participants continued the 4.5-g dose, 8 (33%) increased to 6 g, 8 (33%) increased to 7.5 g, and 3 (13%) increased to 9 g by this data cutoff. Most Group B participants received initial ON-SXB doses of either 9 g (n=27) or 7.5 g (n=24). For Group B participants with >1 visit, 41 maintained their initial dose, 20 increased the dose, and 8 increased the dose but then later decreased it. All but 2 Group B participants with initial 9-g doses of ON-SXB maintained this dose. Twenty participants (20%) discontinued study treatment since the first patient enrolled in July 2020; the primary reason was withdrawal of consent (n=3; 3%). Two (2%) discontinued due to adverse reactions: vivid dreams/anxiety/lightheadedness and lack of efficacy (7.5 g); and difficulty breathing (6 g). Two discontinued due to taste/texture (2%); the remainder for miscellaneous reasons (eg, withdrew consent, could not adhere to schedule, left the country, caring for sick parent/child, wanted to get pregnant, using cannabis). Conclusion These interim data indicate that the majority of participants in all groups titrated to therapeutic and tolerable doses of ON-SXB. Support (If Any) Avadel Pharmaceuticals

Efficacy and immunogenicity of different BCG doses in BALB/c and CB6F1 mice when challenged with H37Rv or Beijing HN878

Two strains of mice (BALB/c and CB6F1) were vaccinated with a range of Bacille Calmette-Guérin (BCG) Danish doses from 3 × 105 to 30 CFU/mouse, followed by aerosol infection with Mtb (H37Rv or West-Beijing HN878 strain). The results indicated that both strains of mice when infected with HN878 exhibited significant protection in their lungs with BCG doses at 3 × 105—3000 CFU (BALB/c) and 3 × 105—300 CFU (CB6F1). Whereas, a significant protection was seen in both strains of mice with BCG doses at 3 × 105—300 CFU when infected with H37Rv. A significant increase in the frequencies of BCG-specific IFNγ+ IL2+ TNFα+ CD4 T cells in the BCG doses at 3 × 105—3000 CFU (BALB/c) and 3 × 105—300 CFU (CB6F1) was seen. The IFNγ+ IL2+ TNFα+ CD4 T cells correlated with the Mtb burden in the lungs of HN878 infected mice (BALB/c and CB6F1) whereas, IFNγ+ TNFα+ CD4 T cells correlated with the BALB/c mice infected with H37Rv or HN878. The BCG dose at 3000 CFU (an equivalent single human dose in the mice by body weight) is protective in both strains of mice infected with H37Rv or HN878 and may serve an interesting dose to test new TB vaccine in a preclinical animal model.

OGG1 co-inhibition antagonizes the tumor-inhibitory effects of targeting MTH1

Cancer cells develop protective adaptations against oxidative DNA damage, providing a strong rationale for targeting DNA repair proteins. There has been a high degree of recent interest in inhibiting the mammalian Nudix pyrophosphatase MutT Homolog 1 (MTH1). MTH1 degrades 8-oxo-dGTP, thus limiting its incorporation into genomic DNA. MTH1 inhibition has variously been shown to induce genomic 8-oxo-dG elevation, genotoxic strand breaks in p53-functional cells, and tumor-inhibitory outcomes. Genomically incorporated 8-oxo-dG is excised by the base excision repair enzyme, 8-oxo-dG glycosylase 1 (OGG1). Thus, OGG1 inhibitors have been developed with the idea that their combination with MTH1 inhibitors will have anti-tumor effects by increasing genomic oxidative DNA damage. However, contradictory to this idea, we found that human lung adenocarcinoma with low OGG1 and MTH1 were robustly represented in patient datasets. Furthermore, OGG1 co-depletion mitigated the extent of DNA strand breaks and cellular senescence in MTH1-depleted p53-wildtype lung adenocarcinoma cells. Similarly, shMTH1-transduced cells were less sensitive to the OGG1 inhibitor, SU0268, than shGFP-transduced counterparts. Although the dual OGG1/MTH1 inhibitor, SU0383, induced greater cytotoxicity than equivalent combined or single doses of its parent scaffold MTH1 and OGG1 inhibitors, IACS-4759 and SU0268, this effect was only observed at the highest concentration assessed. Collectively, using both genetic depletion as well as small molecule inhibitors, our findings suggest that OGG1/MTH1 co-inhibition is unlikely to yield significant tumor-suppressive benefit. Instead such co-inhibition may exert tumor-protective effects by preventing base excision repair-induced DNA nicks and p53 induction, thus potentially conferring a survival advantage to the treated tumors.

Benefit of dosimetry distribution for patients with multiple brain metastases from non-small cell lung cancer by a Cyberknife stereotactic radiosurgery (SRS) system

BackgroundIn order to obtain a high dose conformal index of tumor and steep dose fall-off in healthy tissues for brain metastasis stereotactic radiosurgery (SRS), the aim of this study was to investigate SRS planning optimization by comparing one multiple-lesions plan (MLP) with multiple single-lesion plans (SLPs) for patients with multiple brain metastases using the Cyberknife (CK) system.MethodsFifty non-small cell lung cancer (NSCLC) patients (28 males and 22 females) with 2–4 brain metastases, inter-tumour distances less than 3 cm, were retrospectively replanned with the original prescription dose (12–32 Gy) in the original fractions (1–3). Two different clinical CK SRS plans (SLPs and MLP) were generated for the same patients with the same collimator and prescription isodose line (62–68%) by the CK Multiplan System. Both SLPs and MLP were able to achieve > 95% PTV volume covered prescription dose and met the Timmerman 2011 organs at risk (brainstem, optic nerve and pituitary) constraints.ResultsCompared with those in the SLPs, the maximum dose (Dmax) and mean dose (Dmean) of brainstem in the MLP were reduced 0.22–3.13% (2.62%) and 2.71–12.56% (5.57%), respectively, all P < 0.05. Meanwhile, the volumes of the whole brain minus the tumors that received a single dose equivalent of 8–16 Gy (V8Gy-V16Gy) were effectively reduced in the MLP. The treatment time parameters, the total number of beams and monitor units, of the MLP were reduced by 3.31 and 1.47% (P < 0.05), respectively. Although there were a few differences in the conformity index (CI) and homogeneity index (HI) between the two treatment plans, the differences were not statistically significant (P = 2.94 and 1.08 > 0.05).ConclusionOne multiple-lesions plan for brain metastases could achieve higher precision in the target and lower doses in healthy tissue while shortening the treatment time and improving the treatment efficiency over multiple single-lesion plans.

The influence of the α/β ratio on treatment time iso-effect relationships in the central nervous system

Purpose: To investigate the influence of changes in α/β ratio (range 1.5–3 Gy) on iso-effective doses, with varying treatment time, in spinal cord and central nervous system tissues with comparable radio-sensitivity. It is important to establish if an α/β ratio of 2 Gy, the accepted norm for neuro-oncology iso-effect estimations, can be used.Methods: The rat spinal cord irradiation data of Pop et al. provided ED50 values for radiation myelopathy for treatment times that varied from minutes to ∼6 days. Analysis using biphasic repair kinetics, allowing for variable dose-rates, provided the best fit with repair half-times of 0.19 and 2.16 hr, each providing ∼50% of overall repair; with an α/β ratio 2.47 Gy (CI 1.5–3.95 Gy). Using the above data set, graphical methods were used to investigate changes in the repair parameters for differing fixed α/β ratios between 1.5 and 3.0 Gy. Two different intermittent dose delivery equations were used to evaluate the implications in a radiosurgery setting.Results: Changes in the α/β ratio (1.5–3.0 Gy) have a minor effect on equivalent doses for radiation myelopathy for treatment durations of a few hours. Changing the α/β value from 2 Gy to 2.47 Gy, modified equivalent single doses by < 1% when overall treatment times ranged from 0.1 to 5.0 hr. Significant changes were only found for treatment times longer than 5–10 hr. These two α/β ratios were also compared in a practical radiosurgery situation, using two different models for estimating BED, again there was no significant loss of accuracy.Conclusions: It is reasonable to use an α/β ratio of 2 Gy for CNS tissue, with the same repair half-times as published in the original publication by Pop et al., in situations where the assessment of the BED in radiosurgery is used with other form of radiotherapy. In radiosurgery, the variation in BED with treatment duration (for a fixed physical dose) is very similar, but absolute BED values depend on the α/β value. In radiosurgery, clinical recommendations obtained using BED calculations using the originally proposed α/β ratio of 2.47 Gy are still appropriate. For calculations involving a combination of radiosurgery and other modalities, such as fractionated radiotherapy, it would be appropriate in all cases to apply a value of 2 Gy, the accepted norm in neuro-oncology, without significant loss of accuracy in the radio-surgical component. This may have important applications in retreatment situations.

Toxicology and Pharmacokinetic Studies in Mice and Nonhuman Primates of the Nontoxic, Efficient, Targeted Hexameric FasL: CTLA4-FasL.

Cytotoxic T-lymphocyte antigen 4 (CTLA4)-FasL, a homo-hexameric signal converter protein, is capable of inducing robust apoptosis in malignant cells of the B-cell lineage expressing its cognate B7 and Fas targets, while sparing nonmalignant ones. This fusion protein's striking proapoptotic efficacy stems from its complementary abilities to coordinately activate apoptotic signals and abrogate antiapoptotic ones. A limiting factor in translating FasL or Fas receptor agonists into the clinic has been lethal hepatotoxicity. Here, we establish CTLA4-FasL's in vivo efficacy in multiple murine and xenograft models, for both systemic and subcutaneous tumors. Significantly, good laboratory practice (GLP) toxicology studies in mice indicate that CTLA4-FasL given repeatedly at doses up to five times the effective dose was well-tolerated and resulted in no significant adverse events. An equivalent single dose of CTLA4-FasL administered to nonhuman primates was also well-tolerated, albeit with a moderate dose-dependent leukopenia that was completely reversible. Interestingly, monkey peripheral blood mononuclear cells were more sensitive to CTLA4-FasL-induced apoptosis when tested in vitro. In both species, there was short-term elevation in serum levels of IL6, IL2, and IFNγ, although this was not associated with clinical signs of proinflammatory cytokine release, and further, this cytokine elevation could be completely prevented by dexamethasone premedication. Liver toxicity was not observed in either species, as confirmed by serum liver enzyme levels and histopathologic assessment. In conclusion, CTLA4-FasL emerges from animal model studies as an effective and safe agent for targeted FasL-mediated treatment of B7-expressing aggressive B-cell lymphomas.

Effectiveness of Almagate in gastroesophageal reflux disease: a post-hoc analysis of a randomized cross-over double-blind study

Almagate (aluminium-magnesium hydroxycarbonate hydrate) is a widely used antacid in Spain as an over-the-counter formulation. However, data on the control of acidity in patients with gastroesophageal reflux disease (GERD) are scarce. Herein we report a post-hoc analysis of a randomized crossover double-blind trial (ALR-006; data on file), in which equivalent single oral doses (1.5 g) of two formulations of almagate (AlmaxRetard® and Almax®, Laboratorios Almirall, Barcelona, Spain) were both effective for reflux esophagitis.

Improving stereotactic radiotherapy (SRT) planning process for brain metastases by Cyberknife system: reducing dose distribution in healthy tissues.

Purpose: To pursue high precision dose in lesions and steeper dose fall-off in healthy tissues of brain metastases stereotactic radiotherapy (SRT), this study investigated an opitimized planning by comparison different prescription dose line in the treatment of brain metastases using Cyberknife (CK) Robotic Radiosurgery System.Methods: 77 patients (92 lesions) brain metastases patients CK SRT plans were replanned with 50%-80% (5% internal) prescription dose line to cover more than 95% of the planned target volume (PTV), under the same collimator by Multiplan System. Under the precondition of guaranteeing plans all meet the clinical requirements, the plan evaluation paraments (conformal index (CI) and homogeneity index (HI)), plan treatment time parameters (the total number of beams and monitor units (MU)) and dose distribution of organs at risk (OAR) and healthy brain tissues adjacent to the PTV were analyzed respectively.Resluts: Compared with 70% plans, 65% plans had: 1) average dose (Dmean) and maximum dose (Dmax) of healthy brain tissue outside of the PTV reduced 11.83% and 5.97% markedly; 2) Dmean and Dmax of brainstem decreased 11.43% and 2.86%; 3) the volumes of whole brain minus the tumors received a single dose equivalence of 12 Gy/14 Gy (V12Gy/V14Gy) had marked decline. The dose fall-off was considerably faster in the 60%-65% plans around the PTV and the maximum dose of healthy tissue was prominently lower. While the difference in CI and HI between different plans was not obvious, the plan treatment time was a little higher in 60%-65% plans than 70%-80% plans.Conclusions: Choosing a relatively lower isodose as the prescription dose line for brain metastases CK SRT planing could improve the dosimetry index of target and immensely reduce high dose in healthy brain tissue and OAR.

53BP1/RIF1 signaling promotes cell survival after multifractionated radiotherapy

Multifractionated irradiation is the mainstay of radiation treatment in cancer therapy. Yet, little is known about the cellular DNA repair processes that take place between radiation fractions, even though understanding the molecular mechanisms promoting cancer cell recovery and survival could improve patient outcome and identify new avenues for targeted intervention. To address this knowledge gap, we systematically characterized how cells respond differentially to multifractionated and single-dose radiotherapy, using a combination of genetics-based and functional approaches. We found that both cancer cells and normal fibroblasts exhibited enhanced survival after multifractionated irradiation compared with an equivalent single dose of irradiation, and this effect was entirely dependent on 53BP1-mediated NHEJ. Furthermore, we identified RIF1 as the critical effector of 53BP1. Inhibiting 53BP1 recruitment to damaged chromatin completely abolished the survival advantage after multifractionated irradiation and could not be reversed by suppressing excessive end resection. Analysis of the TCGA database revealed lower expression of 53BP1 pathway genes in prostate cancer, suggesting that multifractionated radiotherapy might be a favorable option for radio-oncologic treatment in this tumor type. We propose that elucidation of DNA repair mechanisms elicited by different irradiation dosing regimens could improve radiotherapy selection for the individual patient and maximize the efficacy of radiotherapy.

Dietary Intake of Vitamin B12 is Better for Restoring a Low B12 Status Than a Daily High-Dose Vitamin Pill: An Experimental Study in Rats.

Vitamin B12 (B12) is present in foods of animal origin, and vegans are encouraged to take supplements with synthetic B12 in order to ensure a sufficient uptake. Recent rat studies suggest that natural (hydroxo-B12, HO-B12) and synthetic (cyano-B12, CN-B12) B12 behave differently in the body. Here, we test if a daily vitamin pill matches dietary B12 in ability to restore a low B12 status in rats. B12-depleted male Wistar rats (n = 60) were divided into five groups (n = 12 in each) and subjected to two weeks intervention with various schemes of B12 supplementation. Two “dietary” groups received a low-B12 chow that was fortified with either HO-B12 or CN-B12 providing a continuous supply. Two “pill” groups received a single daily dose of CN-B12, where the vitamin content either matched or exceeded by factor four the provisions for the “dietary” groups. A control group received the low-B12 chow without B12 fortification. B12 was measured in plasma and tissues. Dietary B12 provides 35% more B12 to the tissues than an equivalent single daily dose (p < 0.0001). Natural B12 delivers 25% more B12 to the liver than synthetic B12 (p = 0.0007). A fourfold increase in B12, supplemented as a single daily dose, does not provide any extra B12 to the tissues (p = 0.45). We conclude that dietary B12 is better at rescuing a low B12 status than a daily vitamin pill.

Acute toxicity and biodistribution of different sized copper nano-particles in rats after oral administration

In order to compare the detailed toxicity of nano‑copper and CuCl2·2H2O (Cu ions) in vivo, the oral toxicity of four differently sized Cu particles (30 nm, 50 nm, 80 nm and 1 μm) on rats was investigated compared with CuCl2·2H2O in acute exposure scenarios. We compared the acute LD50 values and evaluated the kinetics of Cu following a single equivalent dose (200 mg/kg) of five Cu materials. Continuous gavage of nano‑copper for 7 days, the mortality rates, relative organ weights, and hematological, biochemical, and histopathologic characteristics of rats were examined. The results showed that the LD50 values of Cu ions, 30 nm, 50 nm, 80 nm, and 1 μm copper particles were 359.6, 1022, 1750, 2075, and >5000 mg/kg, respectively. Physiological and biochemical indexes indicated that 80 nm nano‑copper (Cu NPs) produced the highest degrees of toxicity in short term. The liver and kidneys were the major organs most affected by Cu NPs, and also the target organs for Cu accumulation. The toxic effects of Cu ions are similar to those of nano‑copper, but they were not the same. Therefore, the toxic effect of nano‑copper is likely to be the result of the dual action of nano‑copper particles and copper ions. Collectively, the acute toxic effects produced by Cu NPs were highly correlated with particle size. Moreover, the toxic effects produced by repeated dosing differed from those produced by a single dose, and this may be due to organ targeting effects that are dependent on the size of the nano-particles.

Increased bioavailability of curcumin using a novel dispersion technology system (LipiSperse®).

Curcumin has been shown to deliver protective effects against numerous degenerative conditions associated with high levels of inflammation and oxidative stress. Owing to its poor bioavailability when delivered orally, it is difficult to deliver a high concentration therapeutic dose. LipiSperse® is a novel delivery system that uses dispersion technology to enhance bioavailability of hydrophobic agents. In this study, we investigated the pharmacokinetics of a commercially available curcumin extract, with or without the curcumin-LipiSperse® delivery complex. Eighteen healthy male and female volunteers participated in this single equivalent dose, randomised, double-blinded study. Seven of those volunteers further participated in the crossover phase of the trial. Plasma concentrations were determined at baseline and at regular intervals over a 24-h period following 750mg of curcuminoid ingestion. In both the parallel and crossover trial, Curcumin with LipiSperse® delivered significantly higher plasma curcuminoid concentrations compared to the raw curcumin product (807 vs 318ng/mL in the crossover trial). The novel delivery system LipiSperse® is safe in humans, and demonstrates superior bioavailability for the supply of curcumin when compared to a standard curcumin extract.

Fractionation enhances acute oligodendrocyte progenitor cell radiation sensitivity and leads to long term depletion.

Ionizing radiation (IR) is commonly used to treat central nervous system (CNS) cancers and metastases. While IR promotes remission, frequent side effects including impaired cognition and white matter loss occur following treatment. Fractionation is used to minimize these CNS late side effects, as it reduces IR effects in differentiated normal tissue, but not rapidly proliferating normal or tumor tissue. However, side effects occur even with the use of fractionated paradigms. Oligodendrocyte progenitor cells (OPCs) are a proliferative population within the CNS affected by radiation. We hypothesized that fractionated radiation would lead to OPC loss, which could contribute to the delayed white matter loss seen after radiation exposure. We found that fractionated IR induced a greater early loss of OPCs than an equivalent single dose exposure. Furthermore, OPC recovery was impaired following fractionated IR. Finally, reduced OPC differentiation and mature oligodendrocyte numbers occurred in single dose and fractionated IR paradigms. This work demonstrates that fractionation does not spare normal brain tissue and, importantly, highlights the sensitivity of OPCs to fractionated IR, suggesting that fractionated schedules may promote white matter dysfunction, a point that should be considered in radiotherapy.

Fullerenol-Based Intracellular Delivery of Methotrexate: A Water-Soluble Nanoconjugate for Enhanced Cytotoxicity and Improved Pharmacokinetics.

Derivatization of fullerenes to polyhydroxylated fullerenes, i.e., fullerenols (FLU), dramatically decreases their toxicity and has been reported to enhance the solubility as well as cellular permeability. In this paper, we report synthesis of FLU as nanocarrier and subsequent chemical conjugation of Methotrexate (MTX) to FLU with a serum-stable and intracellularly hydrolysable ester bond between FLU and MTX. The conjugate was characterized for physiochemical attributes, micromeritics, drug-loading, and drug-release and evaluated for cancer cell-toxicity, cellular-uptake, hemocompatibility, protein binding, and pharmacokinetics. The developed hemocompatible FL-MTX offered lower protein binding vis-à-vis naïve drug and substantially higher drug loading. The conjugate offered pH-dependent release of 38.20 ± 1.19% at systemic pH and 85.67 ± 3.39% at the cancer cell pH. FLU-MTX-treated cells showed significant reduction in IC50 value vis-à-vis the cells treated with pure MTX. Analogously, the results from confocal scanning laser microscopy also confirmed the easy access of the dye-tagged FLU-MTX conjugate to the cell interiors. In pharmacokinetics, the AUC of MTX was enhanced by approx. 6.15 times and plasma half-life was enhanced by 2.45 times, after parenteral administration of single equivalent dose in rodents. FLU-MTX offered enhanced availability of drug to the biological system, meanwhile improved the cancer-cell cytotoxicity, sustained the effective plasma drug concentrations, and offered substantial compatibility to erythrocytes.

Preclinical Metabolism, Pharmacokinetics and In Vivo Analysis of New Blood-Brain-Barrier Penetrant Fingolimod Analogues: FTY720-C2 and FTY720-Mitoxy.

Parkinson’s disease (PD) is a neurodegenerative aging disorder in which postmortem PD brain exhibits neuroinflammation, as well as synucleinopathy-associated protein phosphatase 2A (PP2A) enzymatic activity loss. Based on our translational research, we began evaluating the PD-repurposing-potential of an anti-inflammatory, neuroprotective, and PP2A stimulatory oral drug that is FDA-approved for multiple sclerosis, FTY720 (fingolimod, Gilenya®). We also designed two new FTY720 analogues, FTY720-C2 and FTY720-Mitoxy, with modifications that affect drug potency and mitochondrial localization, respectively. Herein, we describe the metabolic stability and metabolic profiling of FTY720-C2 and FTY720-Mitoxy in liver microsomes and hepatocytes. Using mouse, rat, dog, monkey, and human liver microsomes the intrinsic clearance of FTY720-C2 was 22.5, 79.5, 6.0, 20.2 and 18.3 μL/min/mg; and for FTY720-Mitoxy was 1.8, 7.8, 1.4, 135.0 and 17.5 μL/min/mg, respectively. In hepatocytes, both FTY720-C2 and FTY720-Mitoxy were metabolized from the octyl side chain, generating a series of carboxylic acids similar to the parent FTY720, but without phosphorylated metabolites. To assess absorption and distribution, we gave equivalent single intravenous (IV) or oral doses of FTY720-C2 or FTY720-Mitoxy to C57BL/6 mice, with two mice per time point evaluated. After IV delivery, both FTY720-C2 and FTY720-Mitoxy were rapidly detected in plasma and brain; and reached peak concentrations at the first sampling time points. After oral dosing, FTY720-C2 was present in plasma and brain, although FTY720-Mitoxy was not orally bioavailable. Brain-to-plasma ratio of both compounds increased time-dependently, suggesting a preferential partitioning to the brain. PP2A activity in mouse adrenal gland increased ~2-fold after FTY720-C2 or FTY720-Mitoxy, as compared to untreated controls. In summary, FTY720-C2 and FTY720-Mitoxy both (i) crossed the blood-brain-barrier; (ii) produced metabolites similar to FTY720, except without phosphorylated species that cause S1P1-mediated-immunosuppression; and (iii) stimulated in vivo PP2A activity, all of which encourage additional preclinical assessment.

Abstract CT315: IG-002 Phase 3 data: Absence of correlation between unbound paclitaxel and response in MBC

Abstract Study Purpose: Nab-paclitaxel is a Cremophor-free formulation of paclitaxel with increased systemic level of unbound paclitaxel. It has been suggested that increased exposure to unbound paclitaxel accounted for the increased response rate observed for nab-paclitaxel. This hypothesis was challenged by examining the phase 3 data of IG-002 Paclitaxel (formerly Tocosol-Paclitaxel), where unbound paclitaxel levels were 4X higher than Cremophor-EL Paclitaxel (Taxol®) at Cmax. Methods: PK Clinical Study: The primary objective of this clinical pharmacology study was to compare the pharmacokinetics of unbound (“free”) paclitaxel in plasma ultrafiltrates of patients receiving equivalent paclitaxel doses administered as IG-002 Paclitaxeland as Cremophor-EL Paclitaxel. Eligible patients were required to have an advanced non-hematological malignancy for which there was no curative therapy and for which treatment with a single agent taxane was appropriate. Efficacy Clinical Study: One thousand fifty MBC patients were screened for the study and a total of 821 were randomized to receive either IG-002 (100 mg/m2 weekly, IV) or Cremophor-EL Paclitaxel (80 mg/m2 weekly, IV) until disease progression. Results: A single 175 mg/m² dose of IG-002 Paclitaxel produces a mean 67% higher exposure to unbound paclitaxel, and a mean 108% higher exposure to total paclitaxel, than an equivalent single dose of Cremophor-EL Paclitaxel. A single 175 mg/m² dose of IG-002 Paclitaxel results in greater myelosuppression than an equivalent single dose of Cremophor-EL Paclitaxel, assessed by duration of ANC &amp;lt;1500, &amp;lt;1000 or &amp;lt;500 cells/mm³. Similar neutropenia was observed in the phase 3 trial, where free paclitaxel was expected to be 84% higher. There was significantly more neutropenia (p&amp;lt;0.001) and shift towards higher grades of neutropenia (p&amp;lt;0.001) for IG-002 Paclitaxel compared to Cremophor-EL Paclitaxel. These differences were also seen with leucopenia (p &amp;lt;0.002). However, the primary endpoint of adjudicated overall response rate (ORR) demonstrated an ORR of 44.7% for Cremophor-EL Paclitaxel and 37.4 % for IG-002 Paclitaxel. The hypothesis of non-inferiority of IG-002 Paclitaxel compared to Cremophor-EL Paclitaxel was not statistically significant (1-sided p-value of 0.085). Conclusions: Reexamination of phase 3 data of IG-002 Paclitaxel versus Cremophor-EL Paclitaxel revealed that higher systemic exposure to free paclitaxel resulted in greater bone marrow suppression manifested as neutropenia without concomitant increase in tumor response. The deeper tissue penetration required for tumor response involving albumin-mediated transport of paclitaxel would explain why free paclitaxel was not a predictor of tumor response. Citation Format: Monica Choi, Jeff Hsu, Vuong Trieu. IG-002 Phase 3 data: Absence of correlation between unbound paclitaxel and response in MBC. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT315. doi:10.1158/1538-7445.AM2014-CT315

P08.22 * THE ROLE OF CYBERKNIFE FOR PITUITARY METASTASES

BACKGROUND: Pituitary metastases are found in 1.0-26.7% of cancer patients at autopsy. But clinically very rare. We evaluate the efficacy and safety of CyberKnife treatment in the management of metastatic cancer to the pituitary grand. PATIENTS 13 pituitary metastases (male 6, female 7). Age 47y-69y (median 53y). KPS ≧70. No previous irradiation. METHODS: Treatment system: CyberKnife (G3 or G4), Planning system: On target, Multiplan (Accuray), Calculation model: Ray tracing, Inverse algorithm, Immobilaization: thermoplastic mask, Image: CECT 1mm in thickness + MRI Gd T1WI 1-3mm in thickness, PTV = CTV = GTV, Verification: TLS (Target locating system), 6 axis correction. TREATMENT PROTOCOL: Marginal dose: D95PTV ≧ 95%, iso-dose line 80% (goal), Fractions: tumor size, adjacent to OAR (organs at risk), Tolerable dose of optic appratus: 12Gy (SRS), 21Gy (3fr.), 25Gy (5fr.), 28Gy (7fr.). Tumor volume (PTV): 0.5-18.2 cc (median 2.8 cc), Primary origin: Breast 5, Lung 2, Others 6. Clinical symptom: visual disturbance 11 (85%), diabetes insipidus 5 (38%), diplopia 1 (7.7%), asymptomatic 1 (7.7%). Marginal dose: 18-35 Gy (median 23Gy). RESULTS: Follow up periods 4-31months. Progression free survival: 81.8% (@6m), 63.6% (@12m), 54.5% (@24m). Overall survival: 92.3% (@3m), 84.6% (@6m), 67.3% (@12m), 25.6% (@24m). Maximum dose for optic apparatus BED2 (Gy): 84-229 Gy (median 98.3Gy). Only 1 case became entirely blind 12 months after CyberKnife for 6 months until her death, despite tumor reduction. In this case, maximum dose for optic apparatus BED2 (Gy) was 229 Gy (highest). CONCLUSION: These preliminary results seem to indicate that CyberKnife SRT is a safe, effective and palliative treatment for most patients with pituitary metastasis. To prevent radiation induced optic neuropathy, maximum dose for optic apparatus BED2 (Gy) is under 126 Gy (single dose equivalent: 15Gy). Its safety and efficacy remain to be observed in long-term follow up.

THU0143 Pharmacokinetics, Bioavailability and Safety of A Modified Release Once Daily Formulation of Tofacitinib in Healthy Volunteers

BackgroundTofacitinib is a novel, oral Janus kinase (JAK) inhibitor for the treatment of rheumatoid arthritis (RA). The efficacy and safety of an immediate-release (IR) formulation of tofacitinib, dosed twice daily...