Our Mission
To advance the field of stem cell medicine,
and bring its life-changing treatments
to pets everywhere.

The Gallant Team

  • Aaron Hirschhorn

    Founder and CEO
    As the founder of Gallant, Aaron Hirschhorn brings 20 years of experience operating, advising, and investing in technology companies. Inspired by the impact of regenerative medicine on his own life, Aaron founded Gallant in mid-2018. Previously, Aaron was the Founder and CEO of DogVacay, a consumer marketplace app for dog sitting and dog walking. DogVacay raised $47m from investors including Benchmark Capital and Andreessen Horowitz. The business merged with Rover (Rover.com) in April 2017 to create what is now a $1B pet services company.

    Outside of Gallant, Aaron is a Venture Partner at Bold Capital and has served as a venture investor with Upfront Ventures. Prior to this, he worked at Monitor Group and Kayne Anderson Capital. He is on several private company boards, a member of YPO, an active angel investor, and was a 2016 finalist for E&Y entrepreneur of the year.
  • Davis Brimer

    Co-founder, President and COO
    Davis Brimer has more than 13 years of experience creating new products and markets in the life sciences, human and veterinary medicine industries. Previous to joining Gallant, Davis was the founding CEO and operations lead at Active Life Scientific, where he recruited and collaborated with regenerative medicine experts worldwide, from biotech, big pharma and academia. He has built teams of leading scientists and engineers and led the creation of strategies for the FDA approval of first-to-market products. He is the co-author of seminal, peer-reviewed articles in musculoskeletal medicine and is an expert in identifying opportunities for revenue, marketing, and partnerships in new markets. Davis joined Aaron at Gallant as Co-Founder & COO in 2018 and leads the day-to-day operations of the company, while raising his amazing Dalmation pup Davos.
  • Dr. Linda Black, DVM, PhD

    Chief Scientific Officer
    Dr. Black brings more than 15 years of experience in regenerative medicine with extensive experience in development and commercialization of stem cell therapies for pets. From 2016 to 2019, she served as President and Chief Scientific Officer at Medicus Biosciences, a preclinical biotech firm focused on using polymer technologies for localized drug and stem cell delivery. Prior to Medicus, she served as the VP of Product Development for VetStem Biopharma, the first veterinary stem cell company to provide regenerative therapies to horses, dogs and cats. She authored the first peer reviewed publications describing the safety and efficacy of primary adipose derived stem cells in osteoarthritis and muscle injury in dogs. This culminated with starting and leading a product development team to work on the first off-the-shelf stem cell therapies for dogs with osteoarthritis. She was the founder and CEO of SciStem Therapeutics, which focused on delivering off-the-shelf genetically modified stem cells for bone healing in animals and people. Prior to those roles, Dr. Black consulted exclusively for Merial, Ltd supporting aspects of R&D, marketing, and sales divisions. She is a member of the scientific advisory boards of Medicus Biosciences and Zander Therapeutics. Dr. Black holds a DVM from University of Wisconsin-Madison, a PhD in Cell and Molecular Biology from University of Pennsylvania and completed her post-doctoral fellowship at SmithKline Beecham (GlaxoSmithKline).
  • Jen Rapp

    Chief Marketing Officer
    Jen Rapp has over 18 years of brand building and marketing experience for the world’s most notable brands, including Patagonia, DoorDash, TOMS and Arc’teryx. As Gallant’s CMO she leads growth, brand, PR and creative direction. Prior to joining Gallant, Rapp served as VP of marketing at DoorDash where the company grew from a $650M startup to a $4B+ unicorn during her tenure. She led the rebranding of the company, the launch of Project DASH, the company’s social impact program, and the company’s first national advertising campaign. Previous to DoorDash, Rapp honed her brand building skills, serving as Global Director of Communications at Patagonia for a decade - and as the VP of Communications at TOMS Shoes. She has led both US-based and international teams to launch, evolve, grow these consumer brands into household names and served as the youngest member of Patagonia and TOMS’ leadership teams. Rapp is an untraditional executive. Outside of the office, she is an avid rock climber, skydiver, BASE jumper and pilot. She has spoken publicly about how the experience she’s gained in the mountains can grow businesses, guide decision-making and build risk-management skills. She is also a pet parent to three pups - one of which is the world’s only BASE-jumping dog.
  • Kevin Hicok, MS

    Senior Director of R&D
    Kevin brings 25 years of research and development experience in the fields of stem cell therapeutics. Before joining Gallant as Director of R&D, he held prominent roles in pioneering stem cell companies such as Osiris Therapeutics, Cytori Therapeutics, and VetStem Biopharma. He is an expert in stem cell characterization, identity, potency, and preclinical safety and efficacy study design, and validation of bone marrow and fat derived cell drugs and primary adipose derived cells and tissue products. Kevin has 20 years of experience managing applied research, applying GLP, GTP and cGMP quality standards to research and development practice and significant experience in late stage product development, phase I/phase II clinical trial support. Kevin earned his Bachelor of Science degree at Gustavus Adolphus (St. Peter, MN) and his Masters of Science in Cell and Developmental Biology at the University of Minnesota (Minneapolis, MN).
  • Dr. Jeff Schaffer, DVM

    VP of Business Development
    Dr. Schaffer is a veterinarian with more than 20 years of experience in the field of regenerative medicine. His career roles have spanned the disciplines of clinical veterinary medicine, research scientist and academician. Prior to joining Gallant, Dr. Schaffer was Vice President of sales and marketing and Professional Services for VetStem Biopharma. He is the former Director of Animal Health of PALL Life Sciences, where he oversaw product distribution with more than 100 sales representatives, and the lead scientist in the development, marketing and launch of the Pall V-PET platelet therapy system (PRP). Dr. Schaffer has practiced veterinary medicine at Nassau- Suffolk Vet Hospital, several emergency veterinary hospitals and animal shelters and also worked as a professor in medical and biological subjects at numerous colleges and universities in New York. He is the author of a range of published studies and has established relationships with key opinion leaders in medical, veterinary research and clinical practices. Dr. Schaffer obtained his Doctor of Veterinary Medicine at the University of Perugia.
  • Darryl Rawlings

    Board Member
    Darryl Rawlings has established himself as a leader in medical insurance for cats and dogs. As founder and chief executive officer of Trupanion and founder and member of NAPHIA, Rawlings is setting high standards for a growing industry, expanding public awareness of medical insurance for cats and dogs, and expanding the market across North America.

    His passion for pet health runs deep. When he was 14, his family dog needed surgery that could have lengthened her life for another 12 years. The cost was beyond his parents’ means and they left the veterinary hospital without her. He vowed that someday pets would have even better medical insurance than people do. And Trupanion has fulfilled that promise with medical insurance for cats and dogs that is remarkably better than most human health insurance.

    Trupanion covered its first pet in Canada in 2000 and expanded to the United States in 2008. Since expanding to the U.S., Trupanion has established itself as a market leader and now provides medical insurance for cats and dogs in the United States, Canada, and Puerto Rico. In July 2014, Darryl took this a step further, and lead the company through an IPO. Trupanion is publicly traded on NASDAQ.

    Under his leadership, the company continues to experience consistent growth, with revenue growth in excess of 25% in each of the past 39 quarters. Trupanion now covers more than 500,000 pets.

    Rawlings is a graduate of the British Columbia Institute of Technology. His family includes his wife Caroline, two sons Sam and Bennett, bulldogs Tristen and Priscilla, cat Halle and bird Q.
  • Art Antin

    Arthur J. Antin is the co-founder of VCA, Inc., the largest family of animal care providers nationwide. Since its establishment in 1986, VCA has expanded its operations to include 923 hospitals in 46 U.S. states and five Canadian provinces. It also provides diagnostic services to more than 17,000 independent hospitals, supplies high-tech imaging, and now offers doggy day care and boarding at over 168 locations. Antin has served as VCA’s Chief Operating Officer, Senior Vice President, Secretary and Director. While the company was sold to Mars, Inc. in 2017, Antin continues with VCA as a Senior Advisor working on the company’s expansion into emerging markets in Brazil and Japan.

    Prior to VCA, Mr. Antin worked as an educator for eight years in Yonkers, NY. He then served as Director of Marketing/Investor Relations of AlternaCare Corporation, where he developed and implemented marketing strategies for a network of publicly traded outpatient surgical centers.

    Antin received his AA from Bronx Community College in 1967, BA from City College in 1969, MA in Community Health from New York University in 1973 and Certificate in Computer Programming from Columbia University in 1982.

    Today, Antin serves on the Board of Directors of the Boys and Girls Club of Santa Monica and Western University in Pomona, CA. He lives with his wife, Pat, in Santa Monica, CA, where he enjoys playing golf and cycling.
  • Dr. David Haworth DVM, PhD

    David Haworth is former President of PetSmart Charities in the US and Canada. An independent non-profit, strategic grant-making organization, PetSmart Charities seeks to end pet homelessness by supporting partner organizations and programs that help find loving homes for all pets and celebrates the bond between people and animals. Dr. Haworth was formerly President & CEO at Morris Animal Foundation, Director of Global Alliances within the Business Development group at Pfizer Animal Health (now Zoetis, Inc.), and before that a Director in Pfizer Animal Health's Research & Development division. Prior to joining Pfizer Animal Health, he was an associate veterinarian at a small animal and emergency clinic in Washington State. Dr. Haworth received his bachelor of science in biology from the College of William & Mary and his doctor of veterinary medicine and doctorate of philosophy from Colorado State University. He also completed a postdoctoral fellowship at Colorado State University's Flint Animal Cancer Center.