OSWG Recommended Approaches to the Nonclinical Pharmacokinetic (ADME) Characterization of Therapeutic Oligonucleotides

This white paper summarizes the recommendations of the absorption, distribution, metabolism, and excretion (ADME) Subcommittee of the Oligonucleotide Safety Working Group for the characterization of absorption, distribution, metabolism, and excretion of oligonucleotide (ON) therapeutics in nonclinical studies. In general, the recommended approach is similar to that for small molecule drugs. However, some differences in timing and/or scope may be warranted due to the greater consistency of results across ON classes as compared with the diversity among small molecule classes. For some types of studies, a platform-based approach may be appropriate; once sufficient data are available for the platform, presentation of these data should be sufficient to support development of additional ONs of the same platform. These recommendations can serve as a starting point for nonclinical study design and foundation for discussions with regulatory agencies.

Long-term patency rate of the translocated autologous saphenous vein versus prosthetic material in vascular access surgery for haemodialysis and parenteral nutrition

OBJECTIVE

To evaluate the long-term patency rate of the arteriovenous angioaccess (AVA) with interposition of either autologous or prosthetic material as a last option for vascular access in the upper extremity.

METHODS

This is a retrospective chart review study of all patients who received an AVA with autologous saphenous vein (SV Group, n = 38) or prosthetic material (PTFE Group, n = 25) as a conduit from the year 1996 to 2020 in the Radboud University Medical Center (Radboudumc). Data were retrospectively extracted from two prospectively updated local databases for vascular access, one for haemodialysis (HD) and one for parenteral nutrition (PN). When required, the medical records of each patient were used. Data were eventually collected anonymously and analysed in SPSS 25. Kaplan-Meier life-tables were used for the statistical analysis.

RESULTS

Primary patency at 12 and 48 months was 30% and 20% in the SV group and 45% and 14% in the PTFE group. No significant difference was shown in the median primary patency rate (p = 0.715). Secondary patency at 12 and 48 months was 63% and 39% in the SV group and 55% and 19% in the PTFE group. This was considered a significant difference in median secondary patency in favour of the SV with 41.16 ± 17.67 months against 13.77 ± 10.22 months for PTFE (p = 0.032). The incidence of infection was significantly lower in the SV group (p = 0.0002). A Kaplan-Meier curve could not detect a significant difference in secondary patency between the access for haemodialysis and the access for parenteral nutrition. The secondary patency of the SV in parenteral nutrition access, was significantly higher when compared with PTFE (p = 0.004).

CONCLUSION

The SV can be preferred over PTFE when conduit material is needed for long-term vascular access for HD or PN treatment due to its higher secondary patency and lower infection risk.

Translating pharmacology models effectively to predict therapeutic benefit

Many in vitro and in vivo models are used in pharmacological research to evaluate the role of targeted proteins in a disease. Understanding the translational relevance and limitation of these models for analyzing the disposition, pharmacokinetic/pharmacodynamic (PK/PD) profile, mechanism, and efficacy of a drug, is essential when selecting the most appropriate model of the disease of interest and predicting clinically efficacious doses of the investigational drug. Here, we review selected animal models used in ophthalmology, infectious diseases, oncology, autoimmune diseases, and neuroscience. Each area has specific challenges around translatability and determination of an efficacious dose: new patient-specific dosing methods could help overcome these limitations.

Challenges of non-clinical safety testing for biologics: A Report of the 9th BioSafe European Annual General Membership Meeting

New challenges and other topics in non-clinical safety testing of biotherapeutics were presented and discussed at the nineth European BioSafe Annual General Membership meeting in November 2019. The session topics were selected by European BioSafe organization committee members based on recent company achievements, agency interactions and new data obtained in the non-clinical safety testing of biotherapeutics, for which data sharing would be of interest and considered as valuable information. The presented session topics ranged from strategies of in vitro testing, immunogenicity prediction, bioimaging, and developmental and reproductive toxicology (DART) assessments to first-in-human (FIH) dose prediction and bioanalytical challenges, reflecting the entire space of different areas of expertise and different molecular modalities. During the 9th meeting of the European BioSafe members, the following topics were presented and discussed in 6 main sessions (with 3 or 4 presentations per session) and in three small group breakout sessions: 1) DART assessment with biotherapeutics: what did we learn and where to go?; 2) Non-animal testing strategies; 3) Seeing is believing: new frontiers in imaging; 4) Predicting immunogenicity during early drug development: hope or despair?; 5) Challenges in FIH dose projections; and 6) Non-canonical biologics formats: challenges in bioanalytics, PKPD and biotransformation for complex biologics formats. Small group breakout sessions were organized for team discussion about 3 specific topics: 1) Testing of cellular immune function in vitro and in vivo; 2) MABEL approach (toxicology and pharmacokinetic perspective); and 3) mRNA treatments. This workshop report presents the sessions and discussions at the meeting.

Abstract 6135: Tumor-bearing non-human primates: An unrivaled model for translational cancer immunology research

The translatability of mouse models for the clinical development of cancer immunotherapies remains limited because of substantial differences between the murine and the human immune systems, as well as dissimilarities in the tumor biology. Non-human primates (NHPs) display good homologies towards the human immune system, based on the development of vaccines to several human pathogens. Tumor-bearing monkeys (TBMs) are NHPs that spontaneously developed cancer with progression patterns similar to humans, potentially bridging the experimental gap between early preclinical models and cancer patients treated with immunotherapeutic agents.

TBMs are prevalently rhesus macaques (Macaca mulata) and the most common cancer types are of gastrointestinal, urogenital and endocrine origin. Rhesus macaques are genetically similar to humans and share many characteristics of aging. In both, humans and rhesus macaques, cancer incidence increases with age with the greatest incidence in those over 60 years of age and 20 years, respectively.

TBMs were recently employed to assess the tumor targeting and the pharmacodynamics of the FAP-expressing tumor stroma-targeted immunocytokine FAP-IL2v (Evers et al, AACR 2014, Abstract 2592) and costimulatory agonist FAP-4-1BBL (Claus et al, Science translational Medicine, 2019). In the latter study, we could show targeting of FAP-4-1BBL to FAP-expressing tumor stroma and lymph nodes in a colorectal cancer-bearing rhesus monkey. These data were the basis to investigate tumor targeting of FAP-4-1BBL in an on-going clinical imaging study.

In the present work, we validated further TBMs as translational models for cancer immunotherapy, by performing an imaging/biomarker study in animals exposed to a second FAP-targeted TNFRSF agonist. Two breast cancer-bearing rhesus monkeys (one triple-negative and one Luminal A) were first pre-immunized with a diphtheria/pertussis/tetanus (DTP) vaccine, and then exposed to a single injection of the TNFRSF agonist. In both animals, we could measure a strong systemic immune activation, induction of the TNFRSF agonist in T cells and also tumor regression. These observations validated the applied pre-immunization strategy to induce the TNFRSF protein expression, and confirmed the target to be pursued in the clinical setting.

In conclusion, we consider TBMs as valuable translational animal models to generate proof-of-mechanism evidence in small “signal-seeking” preclinical studies. Tumor targeting, biodistribution, peripheral and intra-tumoral pharmacodynamic activity, pharmacokinetics, immunogenicity, intra-tumoral metabolic activity and tumor regression can all be assessed in TBMs. Because of the similar tumor stroma biology shared between humans and rhesus macaques, TBMs are particularly well suited to test FAP-targeting agents. We anticipate that testing cancer immunotherapy compounds in TBMs could be of high predictability for clinical behavior.

Citation Format: Maurizio Ceppi, Michael Hettich, Volker Teichgräber, Wouter Driessen, Dietrich Tuerck, Estelle Marrer-Berger, Stefan Evers, Flavio Crameri, Bruno Gomes, Jürgen Bachl, Christian Klein, Christina Claus, Maria Amann, Oliver Krieter, Greg Dugan, David Caudell, Jason Grayson, Sai Kumar Solingapuram Kiran, Mark Cline. Tumor-bearing non-human primates: An unrivaled model for translational cancer immunology research [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6135.

Tumor-targeted 4-1BB agonists for combination with T cell bispecific antibodies as off-the-shelf therapy

Endogenous costimulatory molecules on T cells such as 4-1BB (CD137) can be leveraged for cancer immunotherapy. Systemic administration of agonistic anti-4-1BB antibodies, although effective preclinically, has not advanced to phase 3 trials because they have been hampered by both dependency on Fcγ receptor-mediated hyperclustering and hepatotoxicity. To overcome these issues, we engineered proteins simultaneously targeting 4-1BB and a tumor stroma or tumor antigen: FAP-4-1BBL (RG7826) and CD19-4-1BBL. In the presence of a T cell receptor signal, they provide potent T cell costimulation strictly dependent on tumor antigen-mediated hyperclustering without systemic activation by FcγR binding. We could show targeting of FAP-4-1BBL to FAP-expressing tumor stroma and lymph nodes in a colorectal cancer-bearing rhesus monkey. Combination of FAP-4-1BBL with tumor antigen-targeted T cell bispecific (TCB) molecules in human tumor samples led to increased IFN-γ and granzyme B secretion. Further, combination of FAP- or CD19-4-1BBL with CEA-TCB (RG7802) or CD20-TCB (RG6026), respectively, resulted in tumor remission in mouse models, accompanied by intratumoral accumulation of activated effector CD8⁺ T cells. FAP- and CD19-4-1BBL thus represent an off-the-shelf combination immunotherapy without requiring genetic modification of effector cells for the treatment of solid and hematological malignancies.

Optical mesoscopy without the scatter: broadband multispectral optoacoustic mesoscopy

Optical mesoscopy extends the capabilities of biological visualization beyond the limited penetration depth achieved by microscopy. However, imaging of opaque organisms or tissues larger than a few hundred micrometers requires invasive tissue sectioning or chemical treatment of the specimen for clearing photon scattering, an invasive process that is regardless limited with depth. We developed previously unreported broadband optoacoustic mesoscopy as a tomographic modality to enable imaging of optical contrast through several millimeters of tissue, without the need for chemical treatment of tissues. We show that the unique combination of three-dimensional projections over a broad 500 kHz-40 MHz frequency range combined with multi-wavelength illumination is necessary to render broadband multispectral optoacoustic mesoscopy (2B-MSOM) superior to previous optical or optoacoustic mesoscopy implementations.

Phthalocyanine photosensitizers as contrast agents for in vivo photoacoustic tumor imaging

There is a need for contrast agents for non-invasive diagnostic imaging of tumors. Herein, Multispectral Optoacoustic Tomography (MSOT) was employed to evaluate phthalocyanines commonly used in photodynamic therapy as photoacoustic contrast agents. We studied the photoacoustic activity of three water-soluble phthalocyanine photosensitizers: phthalocyanine tetrasulfonic acid (PcS4), Zn(II) phthalocyanine tetrasulfonic acid (ZnPcS4) and Al(III) phthalocyanine chloride tetrasulfonic acid (AlPcS4) in phantom and in tumor-bearing mice to investigate the biodistribution and fate of the phthalocyanines in the biological tissues. PcS4 was observed to grant good contrast between the different reticuloendothelial organs and accumulate in the tumor within an hour of post-administration. ZnPcS4 and AlPcS4 offered little contrast in photoacoustic signals between the organs. PcS4 is a promising photoacoustic contrast agent and can be exploited as a photodiagnostic agent.

Molecular photoacoustic imaging of breast cancer using an actively targeted conjugated polymer

Conjugated polymers (CPs) are upcoming optical contrast agents in view of their unique optical properties and versatile synthetic chemistry. Biofunctionalization of these polymer-based nanoparticles enables molecular imaging of biological processes. In this work, we propose the concept of using a biofunctionalized CP for noninvasive photoacoustic (PA) molecular imaging of breast cancer. In particular, after verifying the PA activity of a CP nanoparticle (CP dots) in phantoms and the targeting efficacy of a folate-functionalized version of the same (folate-CP dots) in vitro, we systemically administered the probe into a folate receptor-positive (FR+ve) MCF-7 breast cancer xenograft model to demonstrate the possible application of folate-CP dots for imaging FR+ve breast cancers in comparison to CP dots with no folate moieties. We observed a strong PA signal at the tumor site of folate-CP dots-administered mice as early as 1 hour after administration as a result of the active targeting of the folate-CP dots to the FR+ve tumor cells but a weak PA signal at the tumor site of CP-dots-administered mice as a result of the passive accumulation of the probe by enhanced permeability and retention effect. We also observed that folate-CP dots produced ~4-fold enhancement in the PA signal in the tumor, when compared to CP dots. These observations demonstrate the great potential of this active-targeting CP to be used as a contrast agent for molecular PA diagnostic imaging in various biomedical applications.

Comprehensive studies of pharmacokinetics and biodistribution of indocyanine green and liposomal indocyanine green by multispectral optoacoustic tomography

A real-time and continuous study of the pharmacokinetics and biodistribution of ICG and Lipo-ICG are performed by multispectral optoacoustic tomography.

Multifunctional photosensitizer-based contrast agents for photoacoustic imaging

Photoacoustic imaging is a novel hybrid imaging modality combining the high spatial resolution of optical imaging with the high penetration depth of ultrasound imaging. Here, for the first time, we evaluate the efficacy of various photosensitizers that are widely used as photodynamic therapeutic (PDT) agents as photoacoustic contrast agents. Photoacoustic imaging of photosensitizers exhibits advantages over fluorescence imaging, which is prone to photobleaching and autofluorescence interference. In this work, we examined the photoacoustic activity of 5 photosensitizers: zinc phthalocyanine, protoporphyrin IX, 2,4-bis [4-(N,N-dibenzylamino)-2,6-dihydroxyphenyl] squaraine, chlorin e6 and methylene blue in phantoms, among which zinc phthalocyanine showed the highest photoacoustic activity. Subsequently, we evaluated its tumor localization efficiency and biodistribution at multiple time points in a murine model using photoacoustic imaging. We observed that the probe localized at the tumor within 10 minutes post injection, reaching peak accumulation around 1 hour and was cleared within 24 hours, thus, demonstrating the potential of photosensitizers as photoacoustic imaging contrast agents in vivo. This means that the known advantages of photosensitizers such as preferential tumor uptake and PDT efficacy can be combined with photoacoustic imaging capabilities to achieve longitudinal monitoring of cancer progression and therapy in vivo.

Abstract 58: Comparative determination of compound delivery to orthotopic and subcutaneous tumors by non-invasive imaging

Cancer is fundamentally a disease of aberrant tissue growth and determining accurate progression in malignancies is of significant importance for the understanding of the heterogeneous growth patterns, and irregular nature of malignant tumors. Here we used two different imaging modalities to detect tumor progression, and highlight the inherent challenges with accurate determination of growth characteristics. The main focus in this study was to examine the differences in compound deposition and uptake into orthotopically and subcutaneously implanted tumors. Several perfusion studies with Indocyanine green (ICG) were performed and compound kinetics and distribution within the tumors were determined by MSOT and FMT-XCT. Multi-Spectral Optoacoustic Tomography (MSOT) is a powerful novel imaging modality that decomposes the spectral responses of endogenous and exogenous chromophores in vivo, with high resolution and at depths ranging from several millimeters to centimeters. Therefore, it can simultaneously detect and separate the signal of endogenous chromophores such as (oxy)hemoglobin and extrinsically administered photo-absorbing agents such as ICG and nanoparticles. FMT-XCT is an imaging system that integrates X-ray computed tomography (XCT) and fluorescence molecular tomography (FMT), enabling quantitative, volumetric detection of fluorescent agents with co-registration of anatomical features. For the subcutaneous model, HT29 human colon adenocarcinoma cells (∼106) were injected subcutaneously in the hind limb of CD1 nude mice (Charles River Laboratories, Germany). For the syngeneic, orthotopic model, Balb/c mice (Charles River Laboratories, Germany) were injected with 4T1 mouse mammary tumor cells (∼0.5x106) into the mammary fat pad. With MSOT imaging after ICG injection (50µg) we were able to show that the vascular perfusion of subcutaneous tumors was limited to the outer edges of the tumor, caused by necrosis within these tumors. The orthotopically implanted tumors were much better perfused and compound delivery throughout the entire tumor was achieved. A major advantage of MSOT imaging compared to FMT-XCT is that contrast agents and oxygenated vs. deoxygenated hemoglobin can be visualized non-invasively at the tumor site simultaneously with high spatial resolution, in real time, and throughout the entire period of tumor growth. Using FMT-XCT we were able to assess further information about the three-dimensional distribution of ICG within the entire animal. These findings show that the heterogeneity of tumors can be visualized non-invasively using MSOT and FMT-XCT. MSOT has the added advantage that endogenous chromophores such as hemoglobin can be resolved simultaneously. These imaging strategies are of critical importance to monitor tumor progression in order to evaluate appropriate treatment regimens and/ or stratify tumors based on oxygenation status.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 58. doi:1538-7445.AM2012-58

Upgrading of sewage treatment plant by sustainable and cost-effective separate treatment of industrial wastewater

The Olburgen sewage treatment plant has been upgraded to improve the effluent quality by implementing a separate and dedicated treatment for industrial (potato) wastewater and reject water. The separate industrial treatment has been realized within a beneficial public-private partnership. The separate treatment of the concentrated flows of industrial wastewater and sludge treatment effluent proved to be more cost-efficient and area and energy efficient than a combined traditional treatment process. The industrial wastewater was first treated in a UASB reactor for biogas production. The UASB reactor effluent was combined with the reject water and treated in a struvite reactor (Phospaq process) followed by a one stage granular sludge nitritation/anammox process. For the first time both reactors where demonstrated on full scale and have been operated stable over a period of 3 years. The recovered struvite has been tested as a suitable substitute for commercial fertilizers. Prolonged exposure of granular anammox biomass to nitrite levels up to 30 mg/l did not result in inhibition of the anammox bacteria in this reactor configuration. The chosen option required a 17 times smaller reactorvolume (20,000 m(3) less volume) and saves electric power by approximately 1.5 GWh per year.

Effect of acid suppression on efficacy of treatment for Helicobacter pylori infection

Eradication of Helicobacter pylori from the stomach by triple therapy with bismuth, tetracycline, and metronidazole cures peptic ulcer disease. We investigated whether concomitant acid inhibition with omeprazole would improve the results of triple therapy. 108 consecutive patients with peptic-ulcer disease and biopsy-proven H pylori infection were randomised to 7 days of triple therapy with or without omeprazole 20 mg twice daily. Patients in the omeprazole-treated group were pretreated with 3 days of omeprazole. Eradication of H pylori was assessed by 10 endoscopic biopsies for urease test, histology, and culture 4-6 weeks after treatment. 53 of 54 (98.1%) patients treated with omeprazole were cured compared with 45 of 54 (83.3%) of those not treated (p = 0.02), a difference in efficacy of 14.8% (95% Cl 4.2-25.4%). Most side effects were mild and did not interfere with compliance; 105 patients (97.2%) finished treatment. Gastro-intestinal side effects were significantly fewer in the omeprazole group. We conclude that the addition of omeprazole to triple therapy improves efficacy, lessens side effects, and is sufficiently efficacious to obviate the need for a diagnostic test of cure in compliant patients.

Role of the intestinal microflora in the formation of DNA and haemoglobin adducts in rats treated with 2-nitrofluorene and 2-aminofluorene by gavage

The role of the intestinal microflora in the metabolic activation of nitroarenes and arylamines was studied in female Wistar rats that received a dose of 1 mmol/kg 2-aminofluorene (2-AF) in sunflower oil by gavage. Another group received the same dose of 2-nitrofluorene (2-NF). A third group of animals was used as controls. Germfree (GF) rats, GF rats with a rat microflora (RM) and GF rats with a human microflora (HM) were treated. After treatment with 2-AF significant differences were observed in the formation of haemoglobin (Hb) adducts and DNA adducts. The 2-AF-Hb adduct level (mean +/- SD) observed in GF rats (0.57 +/- 0.13 mumol/g Hb) was considerably lower than that observed in RM rats (5.1 +/- 0.6) and in HM rats (6.2 +/- 1.3). DNA adduct levels showed the opposite pattern: levels of adducts co-migrating with deoxyguanosin-8-yl-aminofluorene (dG-C8-AF) in liver tissue were higher in GF rats (4.6 +/- 1.4 fmol/micrograms DNA) as compared to RM rats (2.6 +/- 0.04) or HM rats (2.0 +/- 0.7). In lung tissue and white blood cells a similar influence of the intestinal microflora on DNA adduct levels was observed. These results suggest that the intestinal microflora cleaves conjugates of 2-AF or N-hydroxy-2-AF, thus facilitating enterohepatic recirculation of these compounds and enhancing the formation of reactive intermediates binding to Hb. The latter is not observed for DNA adduct formation, indicating that most of these adducts have been formed after a single passage through the liver. After treatment with 2-NF, Hb and DNA adduct levels were much lower. An adduct spot was observed that was not present in rats that received 2-AF. In GF animals only very low levels of DNA adducts co-migrating with dG-C8-AF or deoxyguanosin-8-yl-acetyl-aminofluorene and no Hb adducts were observed, indicating that the metabolic activity of the microflora is an essential step in both Hb and DNA adduct formation.

Effect of organic substrates on biological sulphide oxidation

Neither acetate nor higher fatty acids and glucose have a significant effect on the biotechnological process for sulphide removal at 20 degrees C, in which sulphide is oxidized to sulphur using oxygen. The oxidation of acetate and propionate with oxygen is mainly dependent on the sulphide and oxygen concentrations in the reactor. The occurrence of Thiothrix filaments in sulphide-removing waste-water treatment systems has been investigated using a fixer-film upflow reactor. The influent of this reactor consisted of anaerobically treated paper-mill waste-water, with a sulphide concentration of 140 mg/l. It was found that sulphide loading rate is the decisive parameter as to whether or not Thiothrix will develop in a sulphide-removing reactor.