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Pharmacokinetics, biodistribution and cell uptake of antisense oligonucleotides.

Pharmacokinetic properties of oligonucleotides are largely driven by chemistry of the backbone and thus are sequence independent within a chemical class. Tissue bioavailability (% of administered dose) is assisted by plasma protein binding that limits glomerular filtration and ultimate urinary excretion of oligonucleotides. The substitution of one non-bridging oxygen with the more hydrophobic sulfur atom (phosphorothioate) increases both plasma stability and plasma protein binding and thus, ultimately, tissue bioavailability. Additional modifications of the sugar at the 2′ position, increase RNA binding affinity and significantly increase potency, tissue half-life and prolong RNA inhibitory activity. Oligonucleotides modified in this manner consistently exhibit the highest tissue bioavailability (&gt;90%). Systemic biodistribution is broad, and organs typically with highest concentrations are liver and kidney followed by bone marrow, adipocytes, and lymph nodes. Cell uptake is predominantly mediated by endocytosis. Both size and charge for most oligonucleotides prevents distribution across the blood brain barrier. However, modified single-strand oligonucleotides administered by intrathecal injection into the CSF distribute broadly in the CNS. The majority of intracellular oligonucleotide distribution following systemic or local administration occurs rapidly in just a few hours following administration and is facilitated by rapid endocytotic uptake mechanisms. Further understanding of the intracellular trafficking of oligonucleotides may provide further enhancements in design and ultimate potency of antisense oligonucleotides in the future.
Copyright © 2015. Published by Elsevier B.V.

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Novel tricyclics (e.g., GSK945237) as potent inhibitors of bacterial type IIA topoisomerases.

During the course of our research on the lead optimisation of the NBTI (Novel Bacterial Type II Topoisomerase Inhibitors) class of antibacterials, we discovered a series of tricyclic compounds that showed good Gram-positive and Gram-negative potency. Herein we will discuss the various subunits that were investigated in this series and report advanced studies on compound 1 (GSK945237) which demonstrates good PK and in vivo efficacy properties.
Copyright © 2016. Published by Elsevier Ltd.

Immune-mediated liver injury of the cancer therapeutic antibody catumaxomab targeting EpCAM, CD3 and Fcγ receptors.

The immunotherapeutic catumaxomab targets EpCAM positive cancers and is approved for the treatment of peritoneal carcinomatosis. To assess the safety of intravenous applications a phase 1 clinical trial was initiated. Treatment of EpCAM positive tumor patients with catumaxomab caused dose dependent hepatitis as evidenced by significant elevations in serum alanine- and aspartate aminotransferases, bilirubin, γGT and induction of the acute phase C-reactive protein (CRP) and the cytokines IL6 and IL8. The first patient receiving 10μg catumaxomab experienced fatal acute liver failure which led to the termination of the study. Immmunopathology revealed catumaxomab to bind via its Fc-fragment to FcγR-positive Kupffer cells to stimulate CRP, chemokine and cytokine release. The observed CD3+T-cell margination at activated hepatic macrophages exacerbated T-cell mediated cytotoxicity. Strikingly, the combined Kupffer/T-cell responses against liver cells did not require hepatocytes to be EpCAM-positive. Catumaxomab’s off-target activity involved T-cell mediated lysis of the granzyme B cell death pathway and the molecular interaction of hepatic sinusoidal macrophages with T-cells induced cytolytic hepatitis. Although the bile ducts were surrounded by densely packed lymphocytes these rarely infiltrated the ducts to suggest an intrahepatic cholestasis as the cause of hyperbilirubinaemia. Lastly, evidence for the programming of memory T-cells was observed with one patient that succumbed to his cancer six weeks after the last catumaxomab infusion. In conclusion, our study exemplifies off-target hepatotoxicity with molecularly targeted therapy and highlights the complexities in the clinical development of immunotherapeutic antibodies.

Differential effects of lenalidomide during plasma cell differentiation.

Thalidomide, lenalidomide and pomalidomide have greatly improved the outcome of patients with multiple myeloma. However, their effects on plasma cells, the healthy counterpart of myeloma cells, are unknown. Here, we investigated lenalidomide effects on normal human plasma cell generation using an in vitro model. Lenalidomide inhibited the generation of pre-plasmablasts and early plasma cells, while it moderately affected plasmablast production. It also reduced the expression level of Ikaros, Aiolos, and IRF4 transcription factors, in plasmablasts and early plasma cells. This suggests that their differential sensitivity to lenalidomide is not due to a difference in Ikaros or Aiolos degradation. Lenalidomide also inhibited long-lived plasma cell generation, but did not impair their long-term survival once generated. This last observation is in agreement with the finding that lenalidomide treatment for 3-18 months did not affect the bone marrow healthy plasma cell count in allografted patients with multiple myeloma. Our findings should prompt to investigate whether lenalidomide resistance in patients with multiple myeloma could be associated with the emergence of malignant plasmablasts or long-lived plasma cells that are less sensitive to lenalidomide.

Lost Labor Productivity Costs of Prostate Cancer to Patients and Their Spouses: Evidence From US National Survey Data.

The aim of the study is to estimate lost labor productivity costs of prostate cancer (PC) to patients and their spouses.
This study used a nationally representative database from the United States, the Medical Expenditure Panel Survey, to estimate lost productivity costs attributable to PC for patients and their spouses. We used multivariate methods that controlled for sociodemographic factors and comorbid diseases. Sensitivity analyses were used to mitigate the tendency for prevalence rates to be underreported in surveys.
PC patients had an aggregate national annual lost productivity cost of $5.4 billion ($3601 per individual), whereas their spouses had an aggregate annual lost productivity cost of $3.0 billion ($4013 per individual).
These results enhance our knowledge of lost labor productivity costs of PC morbidity and may inform the management and treatment of PC from an employer’s perspective.