Intratumoral dispersion, retention, systemic biodistribution, and clearance of a small-size tumor necrosis factor-α-expressing MIDGE vector after nonviral in vivo jet-injection gene transfer

For nonviral applications of therapeutic DNA, highly efficient and safe vector systems are of crucial importance. In the majority of nonviral approaches plasmid vectors are in use. A novel minimalistic gene expression vector (MIDGE) has been developed to overcome the limitations of plasmid vectors. This small-size double-stranded linear DNA vector has shown improved transgene expression. However, only limited knowledge on uptake, biodistribution, and clearance of this vector exists. In this study we investigated the intratumoral and systemic biodistribution, clearance, and expression kinetics of the tumor necrosis factor (TNF)-α-carrying MIDGE-CMVhTNF vector in NMRI-nu/nu mice with subcutaneously xenotransplanted human A375 melanoma. Biodistribution was analyzed by quantitative real-time PCR in tumors, blood, and organs 0 to 60 min and 3 to 48 hr after intratumoral jet-injection of 50 μg of MIDGE-CMVhTNF. We examined TNF mRNA expression in tumor tissue and organs, using real-time RT-PCR and TNF-specific ELISA. High levels of MIDGE DNA in the tumor tissue demonstrated efficient gene transfer of the small-size vector, resulting in inhomogeneous DNA dispersion and efficient transgene expression. Intratumoral jet-injection of the vector DNA was accompanied by leakage into the blood circuit and appearance in peripheral organs within 5 min to 6 hr. However, this did not lead to TNF-α expression and was followed by rapid vector clearance resulting in the disappearance of MIDGE DNA 24 hr after gene transfer. These data provide important new information for the kinetics of intratumoral and systemic biodistribution and rapid clearance of the jet-injected small-size MIDGE vector.

A phase II-III clinical study with the immunomodulator MGN1703 in patients with advanced colorectal carcinoma: The IMPACT study

e14152

Background: Based on promising data from a phase 1 study of MGN1703 in patients with metastatic solid tumors including those with CRC, a phase 2-3 study was initiated in patients with advanced CRC having disease control after first-line therapy. MGN1703 is a synthetic DNA-based immunomodulator which acts as an agonist of toll-like receptor 9. The objective of the study is to assess efficacy and safety of treatment with MGN1703 in comparison to placebo. Methods: The IMPACT study is designed as an international, multicentric, randomized double-blind placebo-controlled phase 2-3 study. It is conducted in patients with advanced CRC showing disease control after 1st-line therapy with standard chemotherapy regimen. The study treatment is administered s.c. twice weekly (60 mg MGN1703 or placebo; ratio 2:1). The efficacy and safety of the study treatment will be evaluated based on extensive immunological tests, radiological assessment, safety laboratory results and assessments of the quality of life. The study treatment is continued until tumor progression, intolerable toxicity, exclusion criteria or withdrawal of consent. Results: Up to now, the patients received a maximum of 132 (mean: 32.1) treatment administrations, which equals 66 weeks. Drug-related adverse events (as assessed by the investigator) include mild fever, injection site itching, muscle aching, arthralgia, fatigue, paresthesia, rash, and moderate subfebril temperature and increased ANA in single patients. These represent only 16% of all adverse events reported in the study so far. Nine serious adverse events have been reported and only one was assessed as probably drug-related (“atypical pneumonia”). Local reactions reported in single patients include such symptoms as mild redness and swelling at injection site. Currently no laboratory or clinical signs of dose-limiting toxicities have been reported. Conclusions: The preliminary results of the ongoing clinical study in patients with advanced CRC show a good safety profile of the treatment with MGN1703 at the dosage of 60 mg. Most adverse events which were assessed as possibly drug-related belong to expected study drug reactions known for immune modulating drugs.

Efficacy and safety of cancer vaccine with 4-fold gene-modified allogeneic tumor cells: Results of the phase I/II ASET study in patients with advanced renal cell carcinoma

4636

Background: MGN1601 was tested in the first-in-man phase I-II clinical study in patients with advanced renal cell carcinoma (RCC) who failed several previous therapy lines and had no further standard therapy available. MGN1601 consists of two active pharmaceutical ingredients in fixed combination: fourfold gene-modified allogeneic tumor cells expressing IL-7, GM-CSF, CD80 and CD154 through MIDGE vectors and a TLR-9 agonist, the immunomodulator dSLIM. Methods: The ASET study is a multicentric, single-arm phase I-II clinical trial. Clinical response was evaluated using CT scans (RECIST 1.1 or immune related Response Criteria, irRC). Efficacy data were evaluated in terms of PFS and OS for the intended to treat and the treated per protocol (TPP) populations, clinical parameters and quality of life. Immune response was determined using DTH to MGN1601, LTT assay, frequency and activation of blood cells, and mRNA, chemokine and cytotoxic T cells analysis as well as tumor tissue evaluation. Results: Nine of 19 included patients completed the TPP, the others discontinued the study earlier due to PD. Median PFS in the TPP group was 12 wks (3 months) and OS (not reached yet) 46 wks (11 months). Three patients achieved disease control (1 PR, 2 SD) after 12 wks. Two patients are continuing treatment in the extension phase and are progression free since 37 and 46 wks, respectively. Re-evaluation of tumor response data using irRC revealed 1 additional patient with a delayed tumor response 4 wks after treatment stop. Herewith, 4 out of 9 TPP patients (45%) achieved disease control. Of 7 patients receiving targeted therapy upon stop of study treatment, 4 had substantial objective responses, providing evidence that the study drug is able to render their tumors more vulnerable to subsequent therapies. Immune analysis showed trends towards increases of T-, NKT-cell and pDC frequencies and other immune parameters in those patients with clinical responses, indicating anti-tumor immunity of study treatment. Conclusions: The therapeutic cancer vaccine MGN1601 shows promising efficacy in late stage mRCC patients. Results warrant further clinical studies with MGN1601.

Abstract LB-233: Immune-related efficacy data of the phase 1-2 study of an with fourfold gene-modified allogeneic tumor cell based vaccine in patients with advanced renal cell carcinoma

Background. The first-in-man phase 1-2 clinical study (ASET study) of the cell-based therapeutic cancer vaccine MGN1601 included patients with advanced renal cell carcinoma (RCC) who failed previous therapies and had no further standard therapy available. MGN1601 consists of two active pharmaceutical ingredients in fixed combination: fourfold gene-modified allogeneic tumor cells expressing IL-7, GM-CSF, CD80 and CD154 through MIDGE® vectors and a TLR-9 agonist, the DNA-based immunomodulator dSLIM®. Methods. The ASET study is conducted as a multicentric, open, single-arm Phase 1-2 clinical trial. Clinical response (PD, SD, PR, CR) was evaluated using CT scans according to RECIST 1.1 criteria and immune related Response Criteria (irRC). The efficacy data were evaluated in terms of progression-free survival (PFS) and overall survival (OS) for the intended to treat (ITT) and the treated per protocol (TPP) populations of patients.Immune response was determined by the following parameters: ELISA of serum cytokines and chemokines, DTH to MGN1601, LTT assay to standard antigens, frequency and activation of plasmacytoid dendritic cells (pDC), myeloid dendritic cells (mDC), monocytes, natural killer cells (NK), NKT-, B-, and T cells. Blood mRNA and frequency of cytotoxic T cells by ELISPOT as well as tumor tissue were analyzed in a patient subgroup. Results. Nineteen patients, who had advanced stage RCC and failed up to 7 previous therapy lines (median 3 lines), were included. Nine of these patients completed the treatment phase per protocol (TPP), the others discontinued the study earlier due to PD. Currently, one patient is still in treatment phase. Median PFS in the TPP group was 12 weeks (3 months) and OS (not reached yet) 45 weeks (11 months). Three patients achieved disease control (one PR and two SD) after 12 weeks according to RECIST 1.1 criteria. Two patients are continuing treatment in the extension phase and are progression free since 37 and 46 weeks, respectively. Re-evaluation of tumor response data using irRC revealed one additional patient, who had a delayed tumor response 4 weeks after stop of treatment. Herewith, 4 out of 9 TPP patients (45%) achieved disease control. Of six patients receiving a targeted therapy following progress, four had substantial objective responses, suggesting that the study drug rendered their tumors more vulnerable to subsequent therapies. Immune analysis of the cell populations after 12 weeks showed trends towards increases of T cell, NKT-cell and pDC frequencies in those patients with clinical responses to the therapy, indicating anti-tumor immunity due to the study treatment. Conclusions. The therapeutic cancer vaccine MGN1601 shows promising efficacy in late stage mRCC patients. Results warrant further clinical studies with MGN1601.

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 LB-233. doi:1538-7445.AM2012-LB-233

New safety and efficacy data of the ongoing phase I/II study (ASET Study) with an allogeneic tumor vaccine and adjuvant in patients with metastatic renal cell carcinoma

398

Background: The purpose of this first-in-man phase 1-2 study is to assess safety and efficacy of treatment with investigational drug MGN1601 in patients with advanced renal cell carcinoma. MGN1601 consists of two active ingredients: genetically modified allogeneic (human) cells transfected with four different MIDGE vectors encoding IL-7, GM-CSF, CD80 and CD154 and a synthetic DNA-based immunomodulator dSLIM-30L1, a TLR-9 agonist, acting as adjuvant.

Methods: The ASET study is conducted as multicenter, open, single-arm phase 1-2 study. The study therapy consists of 8 MGN1601 treatments administered as follows: the first 3 treatments are administered weekly, and the consecutive 5 treatments bi-weekly. Patients who achieve disease control are proposed to continue the therapy in an extension phase. Such patients receive 5 further applications up to week 120. In this study, safety and efficacy of the study treatment will be evaluated based on extensive clinical and laboratory assessments, monitoring of patients’ quality of life, immunological tests, and radiological investigations.

Results: Eighteen patients have been included into the study so far and received up to 9 treatments with MGN1601. Eight patients completed the 12 week treatment per protocol (TPP). Two of these patients (25% of TPP) achieved disease control (one PR and one SD) after 12 weeks and currently continue the treatment in the extension phase. 48 adverse events were reported during the treatment phase. Of them, 10% were judged as possibly related, 23% unlikely and 67% as not drug-related by the investigators. Possible adverse events include mild fever, edema of the ankle, exanthema crook of the arm, pruritus crook of the arm and arthralgia intermittent. The therapy is well tolerated – no treatment-limiting toxicities or grade 2–4 toxicities occurred in these patients.

Conclusions: The results of the clinical study in late stage RCC patients show promising efficacy and a favourable safety profile of the cell-based tumor vaccine consisting of genetically modified allogeneic transfected RCC cells and the immunomodulator.

IMPACT study: A phase II-III clinical study with the immunomodulator MGN1703 in patients with advanced colorectal carcincoma

633

Background: The synthetic DNA-based immunomodulator MGN1703 acts as an agonist of toll-like receptor 9. Based on promising data from a phase I study in patients with metastatic solid tumors including those with CRC, a phase II-III study was initiated in patients with advanced CRC having disease control after first-line therapy. The objective of the study is to assess efficacy and safety of the MGN1703 treatment in comparison to placebo.

Methods: The IMPACT study is designed as a randomized double-blind placebo-controlled phase II-III study, which is conducted in patients with advanced CRC showing disease control after first-line therapy with standard chemotherapy regimen. The treatment is administered subcutaneously twice weekly in a ratio 2:1 (60 mg MGN1703 or placebo). The study is conducted in Germany, Austria, France, UK, Czech Republic and Russia, and 129 patients will be recruited into the study. The efficacy and safety of the study treatment will be evaluated based on extensive immunological tests, radiological assessment, safety laboratory results and assessments of the quality of life. The study treatment will be continued until tumor progression, intolerable toxicity, exclusion criteria or withdrawal of consent.

Results: The majority of adverse events were assessed as not drug-related by the investigator. The remaining AEs include mild night sweat (not assessable), mild fever (at three occasions, possible related), and mild arthralgia (certain related) in one patient each. Three SAE have been reported so far of which one was assessed as probably drug-related – atypical pneumonia. Only in single patients local reactions such as mild redness and swelling at injection site were reported. No laboratory or clinical signs of autoimmunity or dose-limiting toxicities were reported, so far.

Conclusions: With these preliminary safety results of the ongoing clinical study in patients with advanced CRC it could be shown that ttreatment with MGN1703 at the dosage of 60 mg is well tolerated and safe. Reported adverse events assessed as possibly drug-related belong to expected study drug reactions known for immune modulating drugs. These events were not accompanied by any signs of autoimmunity.

The innate antiviral immune system of the cat: molecular tools for the measurement of its state of activation

The innate immune system plays a central role in host defence against viruses. While many studies portray mechanisms in early antiviral immune responses of humans and mice, much remains to be discovered about these mechanisms in the cat. With the objective of shedding light on early host-virus interactions in felids, we have developed 12 real-time TaqMan(®) qPCR systems for feline genes relevant to innate responses to viral infection, including those encoding for various IFNα and IFNω subtypes, IFNβ, intracellular antiviral factor Mx, NK cell stimulator IL-15 and effectors perforin and granzyme B, as well as Toll-like receptors (TLRs) 3 and 8. Using these newly developed assays and others previously described, we measured the relative expression of selected markers at early time points after viral infection in vitro and in vivo. Feline embryonic fibroblasts (FEA) inoculated with feline leukemia virus (FeLV) indicated peak levels of IFNα, IFNβ and Mx expression already 6h after infection. In contrast, Crandell-Rees feline kidney (CrFK) cells inoculated with feline herpes virus (FHV) responded to infection with high levels of IFNα and IFNβ only after 24h, and no induction of Mx could be detected. In feline PBMCs challenged in vitro with feline immunodeficiency virus (FIV), maximal expression levels of IFNα, β and ω subtype genes as well as IL-15 and TLRs 3, 7 and 8 were measured between 12 and 24h after infection, whereas expression levels of proinflammatory cytokine gene IL-6 were consistently downregulated until 48h post inoculation. A marginal upregulation of granzyme B was also observed within 3h after infection. In an in vivo experiment, cats challenged with FIV exhibited a 2.4-fold increase in IFNα expression in blood 1 week post infection. We furthermore demonstrate the possibility of stimulating feline immune cells in vitro with various immune response modifiers (IRMs) already known for their immunostimulatory properties in mice and humans, namely Poly IC, Resiquimod (R-848) and dSLIM™, a synthetic oligonucleotide containing several unmethylated CpG motifs. Stimulation of feline PBMCs with dSLIM™ and R-848 effectively enhanced expression of IFNα within 12h by factors of 6 and 12, respectively, and Poly IC induced an increase in Mx mRNA expression of 28-fold. Altogether, we describe new molecular tools and their successful use for the characterization of innate immune responses against viruses in the cat and provide evidence that feline cells can be stimulated by synthetic molecules to enhance their antiviral defence mechanisms.

Preliminary safety results of an ongoing phase I/II clinical study of MGN1601, a tumor vaccine comprising allogeneic, gene-modified, and irradiated tumor cells in combination with an immunomodulator in patients with metastatic renal cell carcinoma (ASET study)

392

Background: MGN1601 is a cell-based RCC tumor vaccine MGN1601 consisting of two active pharmaceutical ingredients: genetically modified allogeneic (human) cells transfected with four different MIDGE vectors encoding IL-7, GM-CSF, CD80 and CD154 and a synthetic DNA-based immunomodulator dSLIM-30L1, a TLR-9 agonist. The vaccine is being developed for treatment of patients with advanced RCC. Its prophylactic and therapeutic anti-tumor activity has been shown in several in-vivo models. A good safety profile of MGN1601 was shown in a wide program of acute and chronic toxicity studies. Based on these promising data, this phase 1/2 study was started in patients with advanced RCC.

Methods: This multicentric open clinical study for the assessment of safety and efficacy of MGN1601 in patients with advanced RCC was initiated in October 2010. A total of 24 patients have to be recruited into the study. The treatment consists of 8 MGN1601 treatments administered as follows: the first 3 treatments are administered on a weekly basis, and the consecutive 5 treatments on a bi-weekly basis. The treatment dose contains 107 transfected tumor cells and 5 mg dSLIM per administration, which has been proven to be safe with a high safety margin in repeated toxicity studies. The efficacy and safety of the study treatment will be evaluated based on extensive immunological tests, radiological assessment, safety laboratory results and assessments of the quality of life. Here, the first safety data are presented.

[Table: see text]

Preliminary results of an ongoing phase II/III clinical study of the TLR9 agonist MGN1703 in patients with advanced colorectal carcinoma with disease control after first-line induction therapy (IMPACT Study)

618

Background: MGN1703 is a synthetic DNA-based immunomodulator, which acts as an agonist of toll-like receptor 9. The antineoplastic activity of MGN1703 was previously shown in several in-vitro and in-vivo models. A good safety profile of MGN1703 was shown in regulatory required acute and chronic toxicity studies. A currently finished phase I study in patients with metastatic solid tumors including those with CRC provided evidence for a favorable safety profile of the investigational drug as well as demonstrated positive preliminary efficacy results. Based on these promising data, a phase II/III study was initiated in patients with advanced CRC.

Methods: This international multicentric randomized placebo-controlled phase II/III clinical study is being conducted in patients with advanced CRC with disease control after first-line induction therapy with standard chemotherapy regimen in combination with bevacizumab. One hundred and twenty nine patients have to be recruited to the study and randomized to be treated ether with MGN1703 or with placebo (with a ratio of 2:1), respectively. The recruited patients are treated twice a week with subcutaneous administration of 60 mg MGN1703. This dose has been proven to be safe in the phase I clinical study. The efficacy and safety of the study treatment will be evaluated based on extensive immunological tests, radiological assessment, safety laboratory results and assessments of the quality of life. The study treatment will be continued up to occurrence of tumor progression, intolerable toxicity, exclusion criteria, and withdrawal of consent or death.

[Table: see text]

Novel optical nanosensors for probing and imaging live cells

This review introduces multifunctional optical nanosensors based on surface-enhanced Raman scattering (SERS) and demonstrates their application in live cells. The novel nanosensors have the potential to improve our understanding of cellular processes on the molecular level. The hybrid sensor consists of gold or silver nanoparticles with an attached reporter species. The sensor can be detected and imaged based on the SERS signature of the reporter. This results in several advantages, such as high spectral specificity, multiplex capabilities, improved contrast, and photostability. SERS sensors not only highlight cellular structures, based on enhanced Raman spectra of intrinsic cellular molecules measured in the local optical fields of the gold nanoparticles, they also provide molecular structural information on their cellular environment. Moreover, the SERS signature of the reporter can deliver information on the local pH value inside a cell at subendosomal resolution. SERS sensors are suitable for one- and two-photon excitation.

FROM THE CLINICAL EDITOR

This review introduces multifunctional optical nanosensors based on surface enhanced Raman scattering (SERS) and demonstrates their application in live cells. These hybrid sensors consist of gold or silver nanoparticles with an attached reporter species. The sensor can be detected and imaged based on the SERS signature of the reporter. SERS sensors highlight cellular structures and provide molecular structural information on their cellular environment. They can also deliver information on the intracellular pH-value at subendosomal resolution.

TLR2-activated human langerhans cells promote Th17 polarization via IL-1beta, TGF-beta and IL-23

The cytokines IL-6, IL-1beta, TGF-beta, and IL-23 are considered to promote Th17 commitment. Langerhans cells (LC) represent DC in the outer skin layers of the epidermis, an environment extensively exposed to pathogenic attack. The question whether organ-resident DC like LC can evoke Th17 immune response is still open. Our results show that upon stimulation by bacterial agonists, epidermal LC and LC-like cells TLR2-dependently acquire the capacity to polarize Th17 cells. In Th17 cells, expression of retinoid orphan receptor gammabeta was detected. To clarify if IL-17(+)cells could arise per se by stimulated LC we did not repress Th1/Th2 driving pathways by antibodies inhibiting differentiation. In CD1c(+)/langerin(+) monocyte-derived LC-like cells (MoLC), macrophage-activating lipopeptide 2, and peptidoglycan (PGN) induced the release of the cytokines IL-6, IL-1beta, and IL-23. TGF-beta, a cytokine required for LC differentiation and survival, was found to be secreted constitutively. Anti-TLR2 inhibited secretion of IL-6, IL-1beta, and IL-23 by MoLC, while TGF-beta was unaffected. The amount of IL-17 and the ratio of IL-17 to IFN-gamma expression was higher in MoLC- than in monocyte-derived DC-cocultured Th cells. Anti-IL-1beta, -TGF-beta and -IL-23 decreased the induction of Th17 cells. Interestingly, blockage of TLR2 on PGN-stimulated MoLC prevented polarization of Th cells into Th17 cells. Thus, our findings indicate a role of TLR2 in eliciting Th17 immune responses in inflamed skin.

Superimpose: a 3D structural superposition server

The Superimposé webserver performs structural similarity searches with a preference towards 3D structure-based methods. Similarities can be detected between small molecules (e.g. drugs), parts of large structures (e.g. binding sites of proteins) and entire proteins. For this purpose, a number of algorithms were implemented and various databases are provided. Superimposé assists the user regarding the selection of a suitable combination of algorithm and database. After the computation on our server infrastructure, a visual assessment of the results is provided. The structure-based in silico screening for similar drug-like compounds enables the detection of scaffold-hoppers with putatively similar effects. The possibility to find similar binding sites can be of special interest in the functional analysis of proteins. The search for structurally similar proteins allows the detection of similar folds with different backbone topology. The Superimposé server is available at: http://bioinformatics.charite.de/superimpose.

SuperPred: drug classification and target prediction

The drug classification scheme of the World Health Organization (WHO) [Anatomical Therapeutic Chemical (ATC)-code] connects chemical classification and therapeutic approach. It is generally accepted that compounds with similar physicochemical properties exhibit similar biological activity. If this hypothesis holds true for drugs, then the ATC-code, the putative medical indication area and potentially the medical target should be predictable on the basis of structural similarity. We have validated that the prediction of the drug class is reliable for WHO-classified drugs. The reliability of the predicted medical effects of the compounds increases with a rising number of (physico-) chemical properties similar to a drug with known function. The web-server translates a user-defined molecule into a structural fingerprint that is compared to about 6300 drugs, which are enriched by 7300 links to molecular targets of the drugs, derived through text mining followed by manual curation. Links to the affected pathways are provided. The similarity to the medical compounds is expressed by the Tanimoto coefficient that gives the structural similarity of two compounds. A similarity score higher than 0.85 results in correct ATC prediction for 81% of all cases. As the biological effect is well predictable, if the structural similarity is sufficient, the web-server allows prognoses about the medical indication area of novel compounds and to find new leads for known targets.

Availability: the system is freely accessible at http://bioinformatics.charite.de/superpred. SuperPred can be obtained via a Creative Commons Attribution Noncommercial-Share Alike 3.0 License.

One- and two-photon excited optical ph probing for cells using surface-enhanced Raman and hyper-Raman nanosensors

We demonstrate spatially resolved probing and imaging of pH in live cells by mobile and biocompatible nanosensors using surface-enhanced Raman scattering (SERS) of 4-mercaptobenzoic acid (pMBA) on gold nanoaggregates. Moreover, we also show that this concept of pH nanosensors can be extended to two-photon excitation by using surface-enhanced hyper-Raman scattering (SEHRS). In addition to the advantages of two-photon excitation, the SEHRS sensor enables measurements over a wide pH range without the use of multiple probes.