The Comparative Immunotherapy Program at the University of Pennsylvania is redefining how we approach cancer treatment by leveraging a comparative medicine model. Its mission is to accelerate the development of innovative immunotherapies for both human and canine patients by studying naturally occurring cancers in dogs—such as osteosarcoma (OS)—to uncover novel treatment strategies.
Born from the need for immune-competent, spontaneous models to evaluate cutting-edge therapies, the program uniquely integrates veterinary and human oncology, fostering cross-disciplinary collaboration. Their groundbreaking work includes an NCI-funded clinical trial investigating engineered invariant Natural Killer T (iNKT) cells as a potential game-changing therapy for metastatic osteosarcoma in dogs, with plans to translate this approach to pediatric OS patients.
Through strategic collaborations, advanced molecular profiling, and patient-centered research, UPenn’s Comparative Immunotherapy Program is bringing hope to the osteosarcoma community—one breakthrough at a time. We asked Nicola Mason, BVetMed, PhD, MRCVS, Director of the Comparative Immunotherapy Program at UPenn to tell us more about this new program.
Can you share the mission of the Comparative Immunotherapy Program at UPenn, what inspired it, and what makes it unique?
The mission of the Comparative Immunotherapy Program is to leverage a comparative approach to understand immune mechanisms of disease and create innovative immunotherapies in areas of unmet need. Through comparative medicine, we look to improve the lives of both animals and humans alike.
There is an increasing need for immune-competent, spontaneous animal “models” to evaluate the safety, tolerability, and efficacy of novel therapies, especially immunotherapies, to accelerate the translation of the most promising approaches into the human clinic. The Comparative Immunotherapy Program was borne out of this need and the recognition that many disease processes that occur in humans also occur spontaneously in companion animals. Cancer and autoimmunity are two such examples. Companion animals suffering from certain cancers and from autoimmunity can serve as a relevant parallel population for the evaluation of novel immunotherapies with the added goal of bringing safer, more effective therapies forward for the good of both humans and dogs. By studying the similarities and differences amongst species, we can learn more about immunobiology, disease pathogenesis, and response to immune modulation. Thus, the vision of the Comparative Immunotherapy Program at UPenn is to foster cross-disciplinary collaborations and facilitate translational research in comparative immunology across departments, schools, and institutions, ultimately to accelerate the implementation of cutting-edge immunotherapies that improve the outcome for humans and companion animals.
The biomedical research community and translational immunologists are increasingly receptive to this concept but oftentimes, researchers do not know how to get started, where to access companion animal tissues, what reagents are available to interrogate, for example, the tumor microenvironment of dogs with spontaneous tumors, or how to perform a clinical trial in companion animals with the disease of interest. The CIP provides information, expertise, and resources that can help researchers explore whether the use of a parallel patient population can help to accelerate their research and their ability to bring novel therapeutics into the clinic in an expedited manner and improve outcomes for human and veterinary patients.
What are some of the most exciting immunotherapy strategies you are currently exploring for osteosarcoma?
We have just begun an NCI-funded clinical trial to investigate the use of genetically engineered, off-the-shelf, immune cells known as invariant Natural Killer T cells (iNKT) to treat dogs with metastatic osteosarcoma (OS). iNKT cells are a rare subset of T cells that have potent cytotoxic and immunomodulatory capabilities and can be transferred from a healthy individual into an unmatched recipient without the need for advanced editing and without causing graft versus host disease (GVHD). Most cellular immunotherapies being explored for the treatment of solid tumors such as OS focus on the adoptive transfer of patient-derived (autologous), engineered T cells or natural killer (NK) cells, and unfortunately, neither approach has resulted in significant improvements in outcome. The use of iNKT cells from a healthy donor dog that are genetically engineered with a chimeric antigen receptor (CAR) to treat spontaneous metastatic OS in dogs is unique. Dr. Rotolo, the Director of Effector Cell Therapies within CIP has spearheaded this approach and has developed a methodology to select donors based on the molecular profile of their iNKT cells. We are extremely excited to bring this off-the-shelf, allogeneic, engineered approach to dogs with metastatic OS who have very few other alternatives, and it is our intention, if successful, to take this approach into children with metastatic OS in a future pediatric clinical trial.
We are also looking at whether LRRC15, an exciting new immune target of an antibody-drug conjugate, is expressed in canine OS, and we are looking to generate fully canine-targeted antibodies against the canine form. This will lead to the generation of a biosimilar antibody-drug conjugate (ADC) and an LRRC15-targeted CAR-T for use alone or in rational combination with other immunotherapies in canine OS patients and could inform future human combination approaches.
Finally, we now have both anti-CTLA4 and anti-PD1 monoclonal antibodies – checkpoint inhibitors - for use in the dog, opening new possibilities to explore the safety and efficacy of checkpoint inhibition in combination with radiotherapy, radiopharmaceuticals, cellular therapies and novel strategies including histotripsy in collaboration with Dr. Tuohy at the College of Veterinary Medicine, Virginia Tech, in canine osteosarcoma patients.
How do canine clinical trials accelerate progress in developing effective treatments for both canine and human osteosarcoma patients?
A major challenge to advancing safe and effective treatments into the human oncology clinic is the lack of pre-clinical models that accurately recapitulate tumor heterogeneity, metastatic behavior, the tumor microenvironment, patient immune competence, and the effects of prior cytotoxic therapies. Immune-competent pet dogs develop spontaneous OS that recapitulates many aspects of OS in humans, and the disease occurs at a much higher incidence in dogs compared to humans (15,000 canine patients versus 800 pediatric/AYA patients per year). As such, more clinical trials can be performed at a faster rate in canine OS patients (particularly when performed through a consortium such as the COTC), and answers can be obtained over a compressed time course in the dog. Furthermore, identifying correlative biomarkers of response can be achieved through serial sampling in canine studies, which enables a greater understanding of the mechanism of action of the trial agent and an iterative process to improve response in subsequent studies. We now have the ability to interrogate primary and metastatic canine tumors through advanced molecular techniques, including whole exome sequencing (WES), scRNA sequencing, digital spatial profiling, DNA methylation analysis, etc., and immunological analysis through immunophenotyping, gene expression profiling, TCR and BCR sequencing, and functional testing. We believe that this will lead to the discovery of correlative biomarkers of response and clinical outcomes that will inform the use of novel therapies, for example, patient stratification, in the pediatric/AYA space. Canine studies are also highly valuable in providing information on safety as well as trial agent dosing and schedule. Since there is no official standard of care in canine OS patients, trial agents can be given in the neo-adjuvant setting, perhaps when patients are more able to respond immunologically. Combination therapies can be explored more readily in dogs and small pilot studies that enable clinicians to identify the most effective treatment to advance into larger studies can be rapidly performed. This is particularly relevant when dealing with OS, where we can leverage the higher incidence of the disease in dogs to rapidly identify the most promising approaches to bring to children.
Can you share a recent breakthrough or promising study from your program that gives hope to patients and families affected by osteosarcoma?
For over 100 years, clinical observations have indicated that the immune system plays a role in controlling OS. This has led to different immunotherapeutic strategies aimed at boosting a patient’s immune response against tumor-associated antigens and/or exploring the use of immune modulators to alter the tumor microenvironment to enable a more effective immune response against metastatic lesions. In collaboration with the COTC at the NIH and 11 academic institutions in the US and Canada, we performed a clinical trial evaluating a highly attenuated HER2 expressing Listeria vector as adjuvant therapy in dogs with appendicular OS following standard of care. The aim was to determine safety and tolerability and identify correlative biomarkers of response. We have recently published this work in a paper: Immunological responses and clinical outcomes in dogs with osteosarcoma receiving standard therapy and a Listeria vaccine expressing HER2. Although this regimen that included 3 doses of the vaccine after carboplatin chemotherapy didn’t prolong disease-free interval or overall survival in the dogs, it revealed that long-term survivors had robust immunological responses to the Listeria vaccine, whereas short-term survivors were unable to respond immunologically to the first dose of vaccine. Interestingly, however, the ability of the short-term survivors to respond to the vaccine improved with the second and third vaccine, raising the question of whether repeat immunizations could restore immune function and lead to improved clinical outcomes. In the recent COG study, pediatric and AYA OS patients received the same vaccine every 3 weeks for 48 weeks - a regimen that the results of our canine study would support. We are now interested in understanding why some canine patients have robust immunological responses to a potent immune stimulus (the listeria vaccine) while others do not and how this influences clinical outcome. We believe that understanding the immune status or “immune fitness” of patients may allow patient stratification into clinical trials using immunotherapies. Understanding what contributes to immune dysfunction and an inability to respond to immunotherapies may also enable us to reverse or improve immune dysfunction and ideally turn non-responders into responders.
What role does collaboration play in your research, and how do you work with other institutions or organizations?
The community of researchers and clinician-scientists engaged in comparative oncology is small, and as such, collaboration amongst individuals in the field is very important. I lead the pre-medical cancer immunotherapy network for canine trials (PRECINCT) – a network and data coordinating center supported by a U24 award from the National Cancer Institute. The network is comprised of basic, translational, and clinician scientists, all with a shared interest in comparative oncology and the performance of clinical immunotherapy trials in pet dogs with spontaneous cancers that can be leveraged to advance human clinical advances. We have organized working groups in areas of correlative biomarkers, and bioinformatics and a recently formed immune checkpoint inhibitor task force. Academic institutions work collaboratively both within this network and outside of the network with important examples being the sharing of reagents, clinical samples, and optimized protocols. Furthermore, to accelerate the performance of clinical trials, it is not uncommon for canine trials to be performed at multiple academic or private referral sites. In these instances, experts in veterinary oncology are invited to participate in a particular study and at the earliest stage, they are brought in to provide feedback on protocol development and performance so the best approach will be implemented to move forward. The Comparative Immunotherapy Program has also initiated community outreach programs to assist in biological sample collections. OS is a problem for human and canine patients, for canine owners, for doctors and veterinarians and researchers alike and it will take a village to solve it. Engaging the community is important to accelerate our work. One such outreach program is a collaboration with the Greyhound Health Initiative (GHI) to procure primary OS tumor samples from Greyhounds and other breeds undergoing standard-of-care amputation for the treatment of the disease. With full owner consent, a portion of the removed tumor is sent to my lab at Penn to accelerate our investigations of analyzing and developing tumor infiltrating lymphocytes (TILs) and genetically engineered TIL therapy for patients in the future. This has been highly rewarding for both the advancement of research and for the owners who contact us directly requesting their dog’s sample be donated to research, as they can contribute to efforts to help combat this disease.
How can patient advocates and families contribute to or support the work that you are doing?
There are two main ways in which patient advocates and families can contribute to our work – firstly, Communication and Engagement and secondly, Funding. Raising awareness of the importance of research to address the undisputed need for better, safer, and gentler treatments for OS is incredibly important. We need therapies to prevent relapse, and we desperately need therapies to effectively treat metastatic disease. Engaging with the community and reaching outside of the community to communicate this need is essential. Research is expensive, and the performance of clinical trials is particularly costly, albeit significantly cheaper in canine patients versus human patients. Furthermore, the advanced techniques now available (such as scRNAseq and spatial transcriptomics) to evaluate immunological responses and identify correlative biomarkers after treatment are expensive and yet so important if we are to advance our understanding of how the immune system can be manipulated to effectively combat this disease. We have been very fortunate in acquiring funding from both federal and private foundation grants to support our comparative research and clinical trial work in OS and we are hopeful that our work will lead to improvements in canine and human OS patients.
Of all the conferences I attend, the MIB FACTOR conference is my favorite as it drives home the importance of the work we and others are doing every day. Interactions with the incredible OS patients and their families inspire my team and me to continue our work as there is much to do, and we hope that in some way, our work will play a part in making it better for children (and dogs!) with OS.
