Backed to the Future

Escher’s passion for science and the potential to help patients is as deeply ingrained in his DNA as his entrepreneurial spirit. It is no surprise that when he talks about his investments, he leads with the science and ends with the business. And in all the three startups he showcases, both go perfectly hand in hand.

Araris: The Hype Next Door

When Araris Biotech first came to Pureos’s attention, the antibody-drug conjugate (ADC) field was quiet. ADCs – cancer treatments that work by attaching a toxic payload to an antibody and directing it precisely at tumour cells – had been around for years, but the clinical results that would eventually send the entire sector into a frenzy hadn’t yet arrived. Escher and his partners looked at the platform, looked at the people, and looked at the linker technology Araris had developed as a spin-off from the Paul Scherrer Institute and ETH Zurich. “We got very excited,” he says. “They ticked many, many boxes.” Pureos led the seed round.

Shortly after they invested, everything changed. Results from other companies in the ADC field came out showing remarkable clinical efficacy across multiple cancer indications, and what had been a quiet area became something close to a gold rush. Billion-dollar collaborations and acquisitions started landing left and right. Pharma companies that hadn’t previously cared about ADC technology suddenly wanted platforms, wanted programs, wanted in. “It started almost a hype in that field,” Escher says.

And Araris just kept developing. Quietly. Methodically. Generating results. But not signing the deals.

It was a case where your competitors getting good results wasn’t a death sentence to your own company- unlike other deep tech verticals, positive biotech results often empower each other.

“We were a little bit under pressure,” Escher says. “Left and right there were these billion dollar deals which happened and everybody was saying: why is Araris not having these deals? Why does nobody want to buy Araris?” His answer, sitting on the board and watching it unfold, was to hold the line. “Sometimes it needs a little bit of time. Sometimes you also need to give the company some air to breathe.”

There was one change Pureos did make. The original CEO was a scientist of deep credibility but, as Escher puts it carefully, “wasn’t the person who could continue telling the story and start the excitement.” One of Pureos’ own venture partners, Dragan Grabulovski, had been serving as chairman of the board, knew the management well, and had spent years working alongside the team. The decision was made to move him into the CEO role. The former CEO stepped down to become Chief Scientific Officer – a position that, in a platform-based biotech, carries enormous weight. “That transition at the end was very smooth,” Escher says. “And at the end he could also see his chance to grow.”

What followed was the kind of accumulation that happens in biotech when the science is right and the patience holds. Chugai, part of the Roche group, signed a research collaboration worth up to USD 780 million. J&J expressed interest. Taiho Pharmaceutical, which had spent a year running its own tests with the Araris platform, saw the results and understood exactly what they meant – that if they didn’t move, someone else would. In March 2025, Taiho acquired Araris Biotech for USD 400 million upfront, with milestone payments of up to USD 740 million. The total potential value: USD 1.14 billion.

“It was a fantastic exit for all the founders and shareholders,” Escher says. “A very nice turn in the end.”

The Brake on the Nerve Cell

NovaGo Therapeutics, a spin-off from the University of Zurich, was Pureos’ very first investment – made in 2019, before the fund had deployed a single other franc. The science behind it goes back decades, to a discovery made by Professor Martin Schwab, who held positions at both the University of Zurich and ETH Zurich. “What Martin Schwab identified was the mechanism that explains one of biology’s more frustrating design features: why, in adults, nerve cells in the central nervous system simply stop growing. Unlike peripheral nerves, which can regenerate after injury, CNS neurons hit a ceiling.” The reason, it turned out, was a specific protein – Nogo-A – that functions as a molecular brake, telling nerve cells in the adult brain and spinal cord to stop extending. Schwab’s work, now standard textbook knowledge, showed that if you could release that brake, the nerve cells would start growing again.

“That’s exactly what you would need in spinal cord injury, in stroke, in other CNS-related diseases,” Escher says. NovaGo is pursuing an anti-Nogo-A antibody called NG004, currently in a Phase 1b clinical trial focused on acute spinal cord injury patients – a population that, to put it plainly, has very few treatment options and for whom even partial restoration of function can be life-changing. In January 2025, the first patient was dosed.

“Initial results are looking very promising,” Escher says. “We are very confident that we are on a very good path.” Pureos is now financing the company to expand into a broader Phase 2 trial.

The Muscle That Became a Factory

The third investment Escher chooses to talk about is the one he describes as closest to his heart – and anyone who has read part one of this series will understand why. PulseSight Therapeutics, based in Paris, is developing a gene therapy for dry age-related macular degeneration, also known as geographic atrophy. It is a blinding disease that predominantly affects the elderly. In Europe, there is not a single approved treatment for it.

“If you get diagnosed with dry AMD you can do nothing,” Escher says. “You just know: within a couple of years, I will be blind.”

PulseSight’s technology is, scientifically, genuinely unusual. The ciliary muscle – the small muscle inside the eye that controls the lens and allows you to focus – is not, at first glance, an obvious therapeutic delivery target. But it is accessible, it is local to the eye, and it is extraordinarily durable. PulseSight has developed a way to introduce DNA plasmids directly into ciliary muscle cells via a process called electro-transfection, turning the muscle into what Escher describes as a kind of “on-site biofactory”. Once the genetic payload is delivered, the muscle produces the therapeutic agent continuously – for a very long period of time. The lead candidate, PST-611, encodes transferrin, a protein that regulates iron levels in the retina. Dysregulated iron is increasingly understood to play a central role in the cell death that drives geographic atrophy.

“The treatment burden for these patients is very reduced compared to the classical intravitreal injections that other wet AMD patients often get,” Escher explains. The therapy is currently completing Phase I, with initial clinical data in dry AMD patients expected to be presented at the ARVO conference in May 2026.

Escher’s involvement in PulseSight is not limited to a board seat. He was deeply involved in the target selection process, drawing directly on his years in ophthalmology at ESBATech. He has been personally connecting the company with retina specialists – using the network built over nearly three decades in the field to open doors that would otherwise take years to reach. “I think it’s really much more than just providing capital,” he says simply.

Pureos is currently assembling a new financing round to take PulseSight into a broader patient population. And when asked what drives him to stay so operationally close to a company at this stage, in this disease area, Escher answers in a way that briefly bypasses the measured language of venture capital altogether. “The day I could shake hands with the patients that we could help,” he says, thinking back to ESBATech’s ophthalmic programs – “that was so satisfactory. For all the sleepless nights, for all the headaches, all the burden – that was totally compensated. And this is, ultimately, the drive.”

What it takes to build the kind of ecosystem that produces companies like these – and why Switzerland is still leaving money on the table – in the final piece: A Matter of Scale.