Reverb Therapeutics is a next-generation biotechnology company on a mission to harness the body’s own immune signals — cytokines — to develop safer, more precise treatments for cancer and autoimmune diseases. Founded in 2022 by biotech veterans David de Graaf and Surjit Dixit, the company is built on a deceptively simple but scientifically ambitious premise: endogenous cytokines, which naturally orchestrate immune responses, can be captured, stabilized, and redirected using bispecific antibodies to amplify their therapeutic impact without systemic side effects.
Reverb’s scientific foundations are rooted in an insight de Graaf had more than a decade ago. Earlier in his career, he led a team at Pfizer that supported a range of preclinical and clinical programs. One of those programs produced a puzzling result. A drug that was designed to inhibit a specific cytokine actually appeared to increase its activity in vivo. “We made a drug that was supposed to stop something, but instead it made it worse,” says de Graaf. “The more of the drug we used, the more biological activity we observed — the exact opposite of what we were expecting.”
Initially baffled, de Graaf soon realized that the drug’s behavior could be explained by the relative half-lives of cytokines and antibodies. Cytokines typically degrade in minutes, while antibodies persist in the body for weeks. When the cytokine and the antibody his team was working on bound together, the complex stabilized, resulting in prolonged and elevated activity instead of suppression. This paradoxical effect had been noted anecdotally in scientific literature for years, but had rarely been explored as a therapeutic mechanism. “I spent the next 12 years thinking about how we could use that piece of biology to make a drug,” says de Graaf.
De Graaf’s idea started to gain traction when the team at Amplitude Ventures introduced him to Surjit Dixit in 2022. Amplitude’s approach to precision medicine and their aptitude for company building was a good fit for both people and they recognized the synergy of bringing together a scientist with deep expertise in bispecific antibody engineering with De Graaf’s strong entrepreneurial experience. Dixit had been exploring whether antibodies could be used to relocate cytokines to specific sites in the body, so the idea took off quickly. “We put our two ideas together and founded Reverb,” says de Graaf. Today, Reverb’s AmplifyR™ platform uses bispecific antibodies to selectively bind to naturally occurring cytokines and direct them to targeted immune cells or diseased tissues — all without altering the cytokines themselves or flooding the entire system.
Unlike traditional biologics, which often require molecular engineering and can be difficult to manufacture, Reverb’s approach has key advantages: low immunogenicity, reduced systemic toxicity, and high manufacturability. “Most companies try to mutate the cytokine or fuse it with other molecules, which can create complex, unstable drugs,” explains de Graaf. “We’re using what the body already makes, which means our drugs are easier to produce and less likely to provoke an unwanted immune response.”
A foundational partnership
Amplitude Ventures didn’t just bring Reverb’s founders together, it helped catalyze the business and played a formative role in shaping it. “Without Amplitude, Reverb wouldn’t have come together,” says de Graaf. “Even before they backed us, they introduced me to my co-founder, pushed our thinking scientifically, and opened doors to top-tier investors and board members. They have a unique understanding of how to motivate scientists and build teams that has been incredibly valuable.”
That support was crucial in Reverb’s early days. At the time of their initial conversations with Amplitude in early 2023, the company didn’t have a lab or data — just a hypothesis and a pitch deck. “They had to trust us,” said de Graaf. “We explained why we thought we were right, and they agreed to fund us before we had a single data point.” That leap of faith enabled the team to generate preclinical evidence showing that their platform could successfully stabilize and redirect cytokines in vitro and in animal models.
Amplitude’s enthusiasm for Reverb and willingness to back the young company stemmed from the founders’ scientific vision and proven leadership. “We saw a huge opportunity to change the way cytokine therapies are delivered,” said Dion Madsen, Managing Partner at Amplitude Ventures. “With Reverb, we are essentially turning up the volume of the body's own immune messengers in a highly targeted way. It’s an entirely new way of thinking about cytokine biology and we are excited about the work David and Surjit are doing to potentially unlock cytokines as powerful therapies without the side effects that have limited them in the past.”
Amplitude ultimately led Reverb’s US$12 million seed round in early 2024. For de Graaf, however, the value that Amplitude provides goes well beyond capital. “They are true partners and, unlike some firms that take a combative stance with their portfolio companies, Amplitude is collaborative,” he says. “They challenge us, but always do so in a constructive manner that helps us think through the hard problems and get to a better place.”
From concept to clinic
Since first launching just a few years ago, Reverb has seen steady growth. The company now employs eight full-time team members and works with several key consultants, including a part-time Chief Medical Officer and specialists in computational pharmacology. Reverb is also preparing for its Series A raise to support the clinical development of its lead program, AMP01.
In just a short time, Reverb’s scientific platform, AmplifyR™, has evolved from a theoretical framework to a validated, preclinical-stage program. The company’s lead asset, AMP01, is advancing toward IND-enabling studies with the goal of entering human trials by the end of 2026 and demonstrating clinical proof-of-concept by 2028. If successful, it would represent a major advancement in cytokine-based medicine — one that avoids many of the drawbacks that have historically hampered this drug class.
What began as a counterintuitive observation has now become a robust and differentiated therapeutic platform. By combining scientific ingenuity, veteran leadership, and a genuinely collaborative venture partner, Reverb Therapeutics is redefining what’s possible in immune modulation and signaling a promising new era in immunotherapy.
