Rejuvenate Bio presents promising results of gene therapy in dogs

Pet longevity research advances with announcement of gene therapy data from pilot study in canines with myxomatous mitral valve disease.

The field of pet longevity research continues to accelerate, and this week saw some interesting results from a Rejuvenate Bio pilot study. Presented at the 26th Annual Meeting of the American Society of Gene and Cell Therapy (ASGCT) in Los Angeles, the study focuses on the use of gene therapy, specifically the gene therapy RJB-01, for the treatment of myxomatous mitral valve disease (MMVD) in canines.

Longevity.Technology: Myxomatous mitral valve disease (MMVD) is the most common, naturally acquired canine heart disease [1]. Not only is it caused by age-related changes to the valves of the heart, but the disease worsens with age and can lead to congestive heart failure and mortality. Mitral valve degeneration increases with age in both humans and dogs, bringing both species heartache in more ways than one.

As this rapidly-accelerating space is demonstrating, research into pet longevity – in this case canine MMVD – is often double bubble as it could not only improve the longevity of our faithful companions but translate into improved treatments for humans as well.

Rejuvenate Bio, a spinout from the Wyss Institute at Harvard, is looking to reverse aging and combat age-related diseases through gene therapy. The company employs proprietary targets, tools and gene delivery systems to develop therapies for cardiac and metabolic diseases. Backed by a Series A financing led by Kendall Capital Partners, Digitalis Ventures, KdT Ventures, and V Capital, Rejuvenate Bio is based in San Diego.

The focal point of Rejuvenate Bio’s study is RJB-01, a gene therapy that uses an adeno-associated virus (AAV) delivery system to upregulate the genes FGF21 and downregulate TGFß1. By targeting the treatment of heart failure in dogs with MMVD, RJB-01 aims to delay the progression of the disease.

The results reported at ASGCT were from a subset of the company’s pilot study of RJB-01 in Cavalier King Charles Spaniels (CKCS) for MMVD. Of all the dogs afflicted with MMVD, Cavalier King Charles Spaniels have one of the highest breed incidences, with rates approaching 80%. MMVD is easily diagnosable with a stethoscope as it initially presents as a heart murmur and is confirmed with an echocardiogram.

In the subset of the pilot study involving Cavalier King Charles Spaniels with MMVD, RJB-01 demonstrated encouraging results; traditionally, MMVD is managed symptomatically with pimobendan and ACE inhibitors, which only address the symptoms rather than tackling the disease. However, Rejuvenate Bio’s gene therapy, when administered alongside pimobendan, showcased substantial benefits in delaying disease progression.

“Mitral valve disease is often fatal for canines at the advanced stage, with no current treatments that can provide a cure. The disease is caused by a malfunction of the mitral valve, which causes congestive heart failure,” said Noah Davidsohn, PhD, Chief Scientific Officer, Rejuvenate Bio.

“The current standard of care is Vetmedin® (pimobendan), paired with ACE inhibitors, but this only treats symptoms and does not address the underlying disease. We’re excited to share these initial results from our pilot study at ASGCT 2023 and we will continue to provide updates as the study progresses [2].”

The administration of RJB-01 and pimobendan to twelve CKCSs yielded a delay in disease progression of over 1.5 years compared with the reported time to progression in all breeds treated with the standard of care alone. Comparatively, when compared to a historical control group treated solely with pimobendan, CKCS treated with RJB-01 and pimobendan experienced an increase in time to progression of approximately 600 days, surpassing 800 days when compared with a placebo [2].

Dogs with MMVD often experience an enlargement of the left atrium due to a malfunctioning mitral valve. Pimobendan managed to limit the increase in heart size, but Rejuvenate Bio’s gene therapy, in conjunction with pimobendan, achieved a reduction in left atrium size over a similar timeframe. Some dogs even reverted to an earlier stage of the disease, highlighting the potential of RJB-01 to reverse the effects of MMVD [2].

Rejuvenate Bio’s study on the efficacy of gene therapy in canines with MMVD brings new hope for the treatment of this condition, and it will be interesting to see whether this is translatable to humans, further exploring the interconnectedness of human and pet longevity research.