CD205 x Tubulin

Adenoid cystic carcinoma (AdCC) is a rare salivary gland malignant tumor that accounts for approximately 1-3% of all head and neck cancers. AdCC is often charaterised by a long natural history with a propensity for indolent but relentless growth and dissemination. Local recurrences and late distant metastases are common findings in about 35% of the patients and associated with a poor prognosis1. AdCC is among the most lethal salivary gland tumors2 with no proven therapy for metastatic disease. Little is known about endogenous immune response directed against AdCC. However, in a relatively large series of 28 AdCC tumor, the immune profiling has shown in most tumors high and frequent programmed death ligand 2 (PD-L2) expression and PD-L1 was generally not expressed on tumor and infiltrating cells3.
The Antibody Drug Conjugates (ADCs) are emerging as a novel therapeutic option in cancer treatment that looks promising for solid tumors. An experimental CD205/Ly75-directed ADC, OBT076 induce potent cytotoxic and antitumor activity. Recently, the combination of immunohistochemistry (IHC) and tissue micro array (TMA) was performed in a series of 46 AdCC, showing a unique profile with both frequent and high expression of CD205/Ly75, much higher than for other solid tumors. In a phase I study, OBT076 demonstrated promising results for 3 patients with 2 partial responses and 1 complete response for a gastric cancer4. In this last patient, analysis showed an increase in PD1+, CD4+ and CD8+ cells suggesting that OBT076 activates the patient's immune response against the tumor, especially PD-1 targeted therapies4.
Based on this rational and on the high level of expression of CD205/Ly75 in AdCC, the hypothesis tested in this study is that OBT076 could be a potential effective treatment for R/M AdCC, which is an orphan lethal disease. The efficacy of OBT076 will be tested either alone or followed by an anti PD-1 inhibitor (Balstilimab) with the hypothesis that OBT076 will induce immune infiltrate that could restore sentivity to PD-1 targeting.

The purpose of this study is to evaluate OBT076, which is a drug that combines an antibody with an anti-cancer drug. This class of drugs are called Antibody-Drug Conjugates (ADC). Antibodies are normally produced in the human body by the immune system to fight infections but can be designed to target cancer cells and deliver an anti-cancer drug. OBT076 is composed of an antibody that targets the CD205 protein on cancer cells and delivers an anti-cancer drug which can kill them. OBT076 is an "Investigational Drug", which means that it is still being studied and has not yet been approved by the US Food and Drug Administration (FDA), the European Medicines Agency (EMA) or any other regulatory authorities to be prescribed by doctors for the treatment of metastatic or recurrent solid tumors. The use of OBT076 in this study is investigational.
This is a Phase I research study designed to look at several dose levels of the study drug to find the highest dose level that is safe and well-tolerated (does not cause unacceptable side effects), and to examine the effects of the study drug in a small group of research participants. The study will also look at the effectiveness of OBT076 as an anti-cancer therapy. Once the optimal dose is determined and safety is assessed, additional research participants will be treated at the optimal dose level to further evaluate safety and effectiveness.