Abstract OT1-06-01: Lymfactin, an investigational adenoviral gene therapy expressing VEGF-C, is currently studied in a double-blind, randomized, placebo-controlled, multicenter, phase 2 clinical study in patients suffering from breast cancer associated secondary lymphedema (BCAL)

Background: Over 15,000 new breast cancer associated secondary lymphedema (BCAL) cases are diagnosed annually in the US. For advanced stage secondary lymphedema, the only current treatment options include conservative therapy and surgical interventions. There is no curative treatment available. Lymfactin is a novel adenovirus type 5-based gene therapy expressing human growth factor VEGF-C, which is highly specific for lymphangiogenesis. Lymfactin is administered directly in the tissue with the compromised lymph flow. By promoting the growth of lymphatic vessels, the aim is to restore a functional lymphatic network and flow.

In a previous first in human Phase 1 clinical study in 15 patients, a single dose of Lymfactin was administered as an adjunct to lymph node transplantation surgery in BCAL patients. Lymfactin was safe and well tolerated, and no dose limiting toxicities were observed. Data at 12 months showed that the volume difference of the affected arm compared to the normal arm decreased >50% in at least half of the patient population. Improvements in the function of the lymphatic system were also observed by quantitative lymphoscintigraphy and quality of life.

We are now investigating the efficacy of Lymfactin in a randomized clinical setting.

Trial design:

We are currently conducting a double-blind, randomized, placebo-controlled, Phase 2 clinical study with Lymfactin in BCAL patients. This multi-center study is enrolling patients in Finland and in Sweden scheduled for lymph node transplantation surgery. In this study a single dose of Lymfactin or placebo (saline) is administered ex vivo in the lymph node transplant during the surgery. A total of 40 patients will be randomized 1:1 to this study.

Main eligibility criteria:

1. Female or male patients with secondary lymphedema associated with the treatment of breast cancer and

a. Has undergone sentinel lymph node biopsies and/or lymph node resection in the axilla on the affected side of their breast cancer with initial N1-N2a staging and lymph node metastasis in ≤ 9 axillary lymph nodes.

b. Requires garment use as a compression treatment for the lymphedema in the affected arm.

c. Has the volume of the affected arm at least 10% greater than the unaffected arm following 7 days without a compression garment.

d. Has the presence of pitting edema in the affected arm without compression garment.

e. Has had lymphedema for less than 5 years.

2. No evidence of recurrent or active breast cancer for at least 2 years after the breast cancer surgery and/or the end of chemotherapy and/or radiotherapy (excluding endocrine treatment).

Specific Aims: Evaluation of the effects of the Lymfactin treatment on the signs and symptoms of lymphedema by comparing the effects of the active study treatment Lymfactin to corresponding placebo up to 24 months post-treatment by measuring the change in the volume of the affected arm, quantitative lymphoscintigraphy, and patient lympedema specific quality of life assessment.

Statistical methods: All efficacy analyses will be performed on the intent-to-treat and per protocol analysis sets. The efficacy data parameters will be summarized using descriptive statistics by treatment group and time point, as appropriate. Due to the nature of the study, there are no set formal statistical hypotheses for the efficacy endpoints, but suitable inferential statistics can be used when feasible.

Present accrual and target accrual: A total of 40 patients are planned to be included in the clinical study. By the end of June 2019, 15 patients have been enrolled.

Contact:

Outi Lahdenperä, MD

CMO

Herantis Pharma Plc

E-mail: outi.lahdenpera@herantis.com

Tel: +358 40 511 3194

Citation Format: Pauliina Hartiala, Outi Lahdenperä, Antti Vuolanto, Anne Saarikko. Lymfactin, an investigational adenoviral gene therapy expressing VEGF-C, is currently studied in a double-blind, randomized, placebo-controlled, multicenter, phase 2 clinical study in patients suffering from breast cancer associated secondary lymphedema (BCAL) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT1-06-01.

Toxicological and bio-distribution profile of a GM-CSF-expressing, double-targeted, chimeric oncolytic adenovirus ONCOS-102 - Support for clinical studies on advanced cancer treatment

The purpose of this work was to carry out preclinical toxicity and bio-distribution studies required for regulatory approval of a clinical trial application for Phase I clinical studies of ONCOS-102 (Ad5/3-D24-GM-CSF) for therapy of advanced cancers (NCT01598129). The study design, route of administration and dosage differs from the clinical protocol and in more detail, investigate bio-distribution and toxicological profile of ONCOS-102 treatment in animal model. The study was carried out in 300 hamsters divided into nine test groups-three bio-distribution groups and six groups for analysis of toxicity. Hamsters received ONCOS-102 by intracardial, intraperitoneal or subcutaneous injections. Additionally, one group was administered twice a week with intraperitoneal injections of Cyclophosphamide. The control animals were administered with NaCl solution without ONCOS-102 in the same volume and the same way. No adverse effects of repeated administration of ONCOS-102 including body weight, food consumption, hematology and clinical chemistry parameters, histopathology and bio-accumulation were observed in the course of 6-month administration and following 3- month recovery period. All obtained findings indicate the treatment clinically safe.

Phase I study with ONCOS-102 for the treatment of solid tumors - an evaluation of clinical response and exploratory analyses of immune markers

Background

We conducted a phase I study with a granulocyte macrophage colony stimulating factor (GMCSF)-expressing oncolytic adenovirus, ONCOS-102, in patients with solid tumors refractory to available treatments. The objectives of the study were to determine the optimal dose for further use and to assess the safety, tolerability and adverse event (AE) profile of ONCOS-102. Further, the response rate and overall survival were evaluated as well as preliminary evidence of disease control. As an exploratory endpoint, the effect of ONCOS 102 on biological correlates was examined.

Methods

The study was conducted using a classic 3 + 3 dose escalation study design involving 12 patients. Patients were repeatedly treated intratumorally with ONCOS-102 plus daily low-dose oral cyclophosphamide (CPO). Tumor response was evaluated with diagnostic positron emission tomography (PET) and computed tomography (CT). Tumor biopsies were collected at baseline and after treatment initiation for analysis of immunological correlates. Peripheral blood mononuclear cells (PBMCs) were collected at baseline and during the study to assess antigen specificity of CD8+ T cells by interferon gamma (IFNγ) enzyme linked immunospot assay (ELISPOT).

Results

No dose limiting toxicity (DLT) or maximum tolerated dose (MTD) was identified for ONCOS-102. Four out of ten (40 %) evaluable patients had disease control based on PET/CT scan at 3 months and median overall survival was 9.3 months. A short-term increase in systemic pro-inflammatory cytokines and a prominent infiltration of TILs to tumors was seen post-treatment in 11 out of 12 patients. Two patients showed marked infiltration of CD8+ T cells to tumors and concomitant systemic induction of tumor-specific CD8+ T cells. Interestingly, high expression levels of genes associated with activated T_H1 cells and T_H1 type immune profile were observed in the post-treatment biopsies of these two patients.

Conclusions

ONCOS-102 is safe and well tolerated at the tested doses. All three examined doses may be used in further development. There was evidence of antitumor immunity and signals of clinical efficacy. Importantly, treatment resulted in infiltration of CD8+ T cells to tumors and up-regulation of PD-L1, highlighting the potential of ONCOS-102 as an immunosensitizing agent for combinatory therapies with checkpoint inhibitors.

Trial registration

NCT01598129. Registered 19/04/2012

Repeated intratumoral administration of ONCOS-102 leads to systemic antitumor CD8+ T-cell response and robust cellular and transcriptional immune activation at tumor site in a patient with ovarian cancer

Adenoviruses are excellent immunotherapeutic agents with a unique ability to prime and boost immune responses. Recombinant adenoviruses cause immunogenic cancer cell death and subsequent release of tumor antigens for antigen presenting cells, resulting in the priming of potent tumor-specific immunity. This effect may be further enhanced by immune-stimulating transgenes expressed by the virus. We report a case of a 38-year-old female with Stage 3 metastatic micropapillary serous carcinoma of the ovary. She was treated in a Phase I study with a granulocyte-macrophage colony stimulating factor (GMCSF)-expressing oncolytic adenovirus, Ad5/3-D24-GMCSF (ONCOS-102). The treatment resulted in progressive infiltration of CD8⁺ lymphocytes into the tumor and concomitant systemic induction of several tumor-specific CD8⁺ T-cell populations. The patient was alive at the latest follow up more than 20 months after initiation of the study.

Local treatment of a pleural mesothelioma tumor with ONCOS-102 induces a systemic antitumor CD8+ T-cell response, prominent infiltration of CD8+ lymphocytes and Th1 type polarization

Late stage cancer is often associated with reduced immune recognition and a highly immunosuppressive tumor microenvironment. The presence of tumor infiltrating lymphocytes (TILs) and specific gene-signatures prior to treatment are linked to good prognosis, while the opposite is true for extensive immunosuppression. The use of adenoviruses as cancer vaccines is a form of active immunotherapy to initialise a tumor-specific immune response that targets the patient's unique tumor antigen repertoire. We report a case of a 68-year-old male with asbestos-related malignant pleural mesothelioma who was treated in a Phase I study with a granulocyte-macrophage colony‑stimulating factor (GM-CSF)-expressing oncolytic adenovirus, Ad5/3-D24-GMCSF (ONCOS-102). The treatment resulted in prominent infiltration of CD8⁺ lymphocytes to tumor, marked induction of systemic antitumor CD8⁺ T-cells and induction of Th1-type polarization in the tumor. These results indicate that ONCOS-102 treatment sensitizes tumors to other immunotherapies by inducing a T-cell positive phenotype to an initially T-cell negative tumor.

Bioreactor for solid-state cultivation of Phlebiopsis gigantea

Phlebiopsis gigantea fungus used in biological control of root rot is currently cultivated commercially in disposable, sterilizable plastic bags. A novel packed bed bioreactor was designed for cultivating P. gigantea and compared to the plastic bag method and to a tray bioreactor. The spore viability of 5.4 x 10(6) c.f.u./g obtained with the packed bed bioreactor was of the same order of magnitude as the viabilities obtained with the other cultivation methods. Furthermore, the packed bed bioreactor was less time and space consuming and easier to operate than the tray bioreactor.

Enhanced Glucose to Fructose Conversion in Acetone with Xylose Isomerase Stabilized by Crystallization and Cross-Linking

The effects of acetone and ethanol on glucose to fructose conversion catalyzed by soluble and cross-linked crystalline (CLXIC) xylose isomerase were studied. Relative to pure buffer solvent, the fructose production rate was more than doubled in 50% acetone. The same kind of increase in the isomerization rate was not seen with ethanol. Increase both in acetone and in ethanol concentration in the reaction solvent enhanced the production of fructose. At 50 degrees C in pure buffer solvent the reaction mixture contained 49% fructose in equilibrium and in 90% acetone the fructose equilibrium content was 64%. Furthermore, CLXIC was relatively stable in the presence of high concentration of acetone: 70-80% of activity was left after incubation for 24 h at 50 degrees C in buffer solutions (pH 7.2) containing 10-90% acetone. In buffer containing 50% ethanol only 2% of the initial activity of CLXIC was retained after 24 h at 50 degrees C. Soluble xylose isomerase was considerably less stable than CLXIC in both acetone- and ethanol-containing solutions. These results show that the addition of acetone enhances the production of fructose from glucose by enhancing the reaction rate and shifting the equilibrium toward fructose. However, xylose isomerase must be in the form of cross-linked crystals for maximal activity and stability.

Enantioselective Affinity Chromatography of a Chiral Drug by Crystalline and Carrier-Bound Antibody Fab Fragment

An antibody Fab fragment, ENA5His, capable of enantioselective affinity chromatographic separation of a chiral drug, finrozole, was stabilized against organic solvents by chemical cross-linking. High concentration of methanol is needed to release the bound drug from the antibody fragment. However, in native form the antibody fragment is unstable at these conditions. We used cross-linked protein crystal technology to stabilize the antibody fragment molecule. Glutaraldehyde cross-linked ENA5His crystals (CLAC) packed in a column separated pure enantiomers from the racemic mixture of the drug. CLAC was totally stable at the elution conditions, enabling reuse of the immunoaffinity column packed with CLAC. However, the specific drug enantiomer binding capacity of CLAC was only 50% of the corresponding capacity of immobilized ENA5His. We were also able to cross-link immobilized ENA5His by glutaraldehyde. This method produced a protein matrix with high activity and stability in the elution conditions.