lorukafusp alfa (APN301)

This study advances CAHA detection strategies and reports the kinetics of CAHA following IT-IC in dogs with spontaneous melanoma.

P1/2, N=8, Active, not recruiting, University of Wisconsin, Madison | Suspended --> Active, not recruiting | N=61 --> 8

Normal canine sera did not mediate binding inhibition. This study advances CAHA detection strategies and reports the kinetics of CAHA following IT-IC in dogs with spontaneous melanoma.

P1/2, N=61, Suspended, University of Wisconsin, Madison | Trial completion date: Aug 2025 --> Aug 2026 | Trial primary completion date: Aug 2024 --> Aug 2025

First, we demonstrate that 9464D-GD2 is nonresponsive to a preferred salvage regimen: anti-GD2 with temozolomide and irinotecan. Second, we have previously shown that adding agonist anti-CD40 mAb and CpG to a regimen of radiotherapy, anti-GD2/IL2 immunocytokine and anti-CTLA-4, cured a substantial fraction of mice bearing small 9464D-GD2 tumors; here, we further characterize this regimen by showing that radiotherapy and hu14.18-IL2 are necessary components, while anti-CTLA-4, anti-CD40, or CpG can individually be removed, and CpG and anti-CTLA-4 can be removed together, while maintaining efficacy. We have developed and characterized a regimen that can cure mice of a high-risk neuroblastoma that is refractory to the current clinical regimen for relapsed/refractory disease. Ongoing preclinical work is directed towards ways to potentially translate these findings to a regimen appropriate for clinical testing.

In a phase I clinical trial, administration of 3xTx (with an immunocytokine fusion of tumor-specific antibody and IL-2, hu14.18-IL2) to subjects with metastatic melanoma increases peripheral CD8 T cell effector polyfunctionality...NK cell depletion increases T infiltration, diminishing CD8 T cell-dependent antitumor response. These findings demonstrate that NK cells sustain and propagate CD8 T cell immunity following 3xTx.

We have previously shown that an intratumoral (IT) injection of the hu14.18-IL2 immunocytokine (IC), an anti-GD2 antibody linked to interleukin 2, can serve as an in situ vaccine and synergize with local radiotherapy (RT) to induce T cell-mediated antitumor effects. Cured mice developed immunological memory as they were able to reject B78 tumor rechallenge. Taken together, these preclinical results show that CY can augment the antitumor efficacy of IT- IC, given alone or in combination with local RT, suggesting potential benefit in clinical testing of these combinations.

Using an in situ vaccine (ISV) regimen that includes a combination therapy of radiation (given at D0) with hu14.18-IL2 immunocytokine [anti-GD2 linked to IL2, (Anyxis Immuno-Oncology GmbH (Austria)); given at D5-D9], we can cure mice of large B78 melanoma tumors (B78s)...MHCII expression on tumors can directly engage CD4 cytotoxic T cells, suggesting an important role in the response to immunotherapy for CD4 T cells in melanoma tumors that express MHCII. Understanding the cellular and molecular mechanisms involved in the ISV-induced immune recognition and destruction of B78 may guide future improvements of this clinically-relevant immunotherapy regimen.

This therapy includes external beam radiation, intratumoral hu14.18-IL2 immunocytokine (anti-GD2 mAb fused to IL2, provided by Anyxis Immuno-Oncology GmbH of Vienna, Austria), and intraperitoneal anti-CTLA-4 leading to in situ vaccination and cure of GD2+ murine tumors... These results show that in vivo metabolic imaging enables single cell quantification of metabolic changes in tumor and immune cells during therapy. Combined with other traditional assays, we can elucidate key immune cell populations and the crucial timepoints during therapy where changes are occurring. With continued efforts, this imaging platform may be leveraged to develop new combinations of immunotherapies.

Additionally, we have illustrated that NK cells exhibited enhanced cytotoxicity toward NB cells (14% reduction of NB cells over 90 minutes) when given a combination treatment of our inhibitor and the immunocytokine ch14.18-IL2. Herein we describe the synthesis and biological evaluation of small molecule CD38 inhibitors and demonstrate their potential utility as a novel approach to NB immunotherapy. These compounds represent the first examples of small molecules that stimulate immune function for the treatment of cancer.

We report a novel use for low-dose RT, not as a direct antitumor modality but as an immunomodulator capable of driving and expanding antitumor immunity against metastatic tumor sites following ISV.

A 9-marker multi-color immunophenotyping panel for flow cytometry (CD3, CD5, CD4, CD8, CD14, CD21, CD25, FoxP3, and PD-1) was optimized using cryopreserved healthy canine PBMC and will be used to assay PBMC from pre and post-treatment timepoints for the protocol treatment dogs. Conclusions IT-IC in combination with local RT in canine melanoma is safe and has antitumor activity with potential to inform clinical development of IT-IC in melanoma patients.