During the first year that the project has been active, we have made progress toward our objectives. The project goals have not been modified.
Our overall objective is to determine a clinically optimal dose and estimate the efficacy of propranolol in dogs with hemangiosarcoma when given as an adjunct to chemotherapy.
Specifically:Objective 1: We will confirm the tolerability and estimate the clinical benefit of propranolol in combination with doxorubicin.
Objective 2: We will assess the circulating drug levels of propranolol after long-term administration to dogs with hemangiosarcoma to determine if there is a correlation between plasma drug concentration and treatment effect. We will also determine if propranolol alters the plasma levels (exposure) of doxorubicin in dogs receiving propranolol and compare these levels to those found in the published literature for dogs receiving doxorubicin. Collection of these data will allow us to better understand how these drugs may be working together.
We opened the trial on July 1, 2019. As of June 23, 2020, we enrolled six dogs in the study. Importantly, we were able to enroll dogs in all three dose cohorts (0.8 1.0, 1.3 mg/kg), and no dose limiting toxicities were noted in any of the dogs enrolled.
Propranolol and doxorubicin levels in the plasma from four of the dogs has been analyzed, and analysis of samples from the fifth and sixth dogs are pending.
The study has been delayed by approximately four months due to the COVID-19 pandemic. Enrollment was halted at all three study sites (University of Minnesota, University of Pennsylvania, Purdue University) in early to mid-March. Enrollment has now resumed at the University of Minnesota as of June 22, 2020; enrollment is expected to resume at the University of Pennsylvania and Purdue University in July.
Our plans are to continue to screen and enroll dogs into the study with the goal of enrolling another 8-10 dogs within the next 6 months. We also plan to complete the initial analysis of drug levels in the plasma samples during this time.