Welcome to Partnology’s Biotech Leader Spotlight Series, where we highlight the remarkable accomplishments and visionary leadership of biotech industry pioneers. This series is about showcasing the groundbreaking strides made by exceptional leaders who have transformed scientific possibilities into tangible realities. Through insightful interviews, we invite you to join us in following the inspiring journeys of these executives who continue to shape the landscape of the biotech industry. This week we are recognizing:
Nathalie Dubois-Stringfellow, Ph.D. has served as Chief Development Officer of Sangamo Therapeutics, Inc. since August 2022 and is responsible for overseeing the strategy and execution of all development programs which integrate Clinical Science and Operations, Regulatory Affairs, Development Sciences and Program and Portfolio Management for Sangamo’s wholly owned and partnered programs. She has over 30 years of experience implementing and managing preclinical and clinical development of biologic therapies in oncology, as well as immune, infectious and genetic diseases. More recently she has led teams developing gene and cell therapy products for hemophilia, hemoglobinopathies, HIV, lysosomal diseases, neurodegenerative diseases and renal transplant. Dr. Dubois-Stringfellow joined Sangamo in January 2011 as Senior Director, Project Management and later served as our Vice President, Product Development and Management from January 2016 to September 2019 and as our Senior Vice President, Product Development and Management from September 2019 to August 2022. Prior to joining Sangamo, she worked in Discovery Research, Preclinical Research, Project Leadership, Clinical Development and Portfolio Management at Chiron Corp., Bayer Corp., Signature Biosciences, Inc. and XOMA LLC. Dr. Dubois-Stringfellow received her M.S. in Genetics and Immunology and her Ph.D. in Human Genetics from the Université Pierre et Marie Curie in Paris, France.
You’ve been at Sangamo for over a decade, rising through multiple leadership roles across discovery, preclinical, clinical, and portfolio management. How has your approach to development strategy evolved over that time?
I think one of the most important things early on is choosing our projects carefully. There may be exciting science, but does it translate into a real product? That’s the key.
We work closely with research to ensure the product profile is aligned with both the company’s mission and a true unmet medical need. It’s also critical to evaluate parallel activities across departments to accelerate development timelines. From the start, we need to ensure that all functions are working in concert—not in silos.
When it comes to selecting programs in gene and cell therapy, there are many areas of unmet need and many ways we can apply our technology. But as a small biotech, we need to be very thoughtful about which programs offer the greatest value—whether for partnering or for advancing internally—to ultimately reach patients as quickly as possible.
Sangamo’s work spans a broad range of therapeutic areas—from hemophilia and HIV to neurodegenerative diseases. How do you prioritize programs and allocate resources across such a diverse pipeline?
The company has really evolved over the past few years, driven both by advances in our own technology and broader progress in the cell and gene therapy field. We’ve had to stay constantly on top of competitive intelligence and find new ways to accelerate our programs.
A good example is our Fabry program. Our Phase 1/2 trial delivered some truly impactful results. We saw the potential for a rapid path to approval, so we approached the regulators to ask if our data might support an accelerated approval pathway—and they agreed. That was a major milestone. It highlights how important it is in biotech to understand not just the value of a program, but the speed at which it can move forward. We’re operating with limited resources and funds, so we have to focus on what will be most impactful and efficient.
We also had to refocus the company in the past few years, particularly around the most promising and groundbreaking discoveries. The biotech sector has been through a difficult period—many companies have had to downsize, pivot, or even shut down. We also went through a reduction in force, and that process pushed us to prioritize the most compelling assets in our pipeline.
In addition to Fabry, we made the strategic decision to focus heavily on neurology. We had made a significant discovery—a best-in-class, blood-brain barrier–penetrant capsid that enables us to deliver therapeutics directly to the brain. Given the high unmet need in neurology, this was a clear direction for us.
We also have a strong advantage with our zinc finger protein-based epigenetic regulators, which give us a powerful tool to address a wide range of neurological diseases.
Finally, partnerships remain a key part of our strategy. We’re always evaluating which programs can be partnered to bring in external funding or accelerate development through collaboration with larger companies that have more resources. At the same time, we’re committed to advancing a pipeline that remains innovative and tightly focused—leveraging the unique tools and expertise we’ve built here at Sangamo.
Which therapeutic area or program in Sangamo’s pipeline do you find most technically or strategically exciting right now—and why?
Our Fabry program is incredibly exciting right now as we prepare to file a Biologics License Application (BLA) for accelerated approval. Fabry is a devastating disease with a wide range of symptoms, and current treatment options are limited. The standard of care—enzyme replacement therapy—is extremely burdensome. It requires IV infusions every two weeks, often lasting several hours, and even then, it doesn’t address all the symptoms patients experience.
In contrast, our gene therapy results have been very promising. For the first time at Sangamo, we’re preparing to file a BLA, and as a drug developer, this is what you work toward—bringing a therapy all the way to patients. It’s a significant and thrilling milestone for us.
The other area we’re deeply excited about is our neurology pipeline. In our preclinical models, we’ve demonstrated that we can successfully deliver genes to the brain—to the neurons themselves—to potentially treat a variety of neurological diseases. This includes more common conditions like Parkinson’s and Alzheimer’s, but also rare and severe disorders like prion disease.
You may be familiar with prion disease—it’s often associated with “Mad Cow” disease—but there are also sporadic human cases. Tragically, once diagnosed, patients typically have a life expectancy of only six months to a year. There are currently no treatment options. So the possibility that our platform could offer a therapeutic solution is incredibly meaningful.
What makes our approach especially powerful is the combination of our delivery technology—a best-in-class blood-brain barrier–penetrant capsid—and our zinc finger protein-based gene regulators, which allow us to modulate gene expression precisely. This pairing gives us a unique opportunity to address a broad range of neurological diseases. In many ways, the sky’s the limit.
Of course, we need to be strategic. We can’t do everything. So we’re carefully selecting programs based on speed to clinical proof of concept, which delivers the greatest value for the company—and more importantly, can accelerate therapies to patients who need them most.
How do you approach “go/no-go” decisions for programs at critical development inflection points? What data or frameworks do you rely on most?
First and foremost, we have to design the product—starting with the design of the zinc finger protein (ZFP). This design needs to be incredibly specific, because in cell and gene therapy, we’re often talking about a one-time treatment. Once it’s delivered, it’s not something you can take back. The vector remains active for a long time—potentially permanently—so the product must be exquisitely and exclusively targeted.
That specificity is established during the research phase, and I have to say, our technology at Sangamo is truly impressive in that regard. After selecting the right candidate ZFP, we then incorporate our delivery system—which we believe we’ve optimized—and move into preclinical proof-of-concept studies.
At that stage, we want to confirm whether the ZFP’s expression achieves the desired efficacy, and whether it aligns with what we would expect to see in humans. And, of course, we assess the safety profile. So I would say the key go/no-go decision points include:
- Selecting the right ZFP with the best possible specificity and therapeutic potential.
- Demonstrating efficacy and safety in preclinical models.
If we see off-target effects, we have to pause and reassess. That might mean terminating the program—though that’s extremely rare with our platform—or going back to the drawing board to design a new candidate. Similarly, if the efficacy isn’t there in disease models, we have to question whether the hypothesis is valid or whether we need a new ZFP altogether.
We also need to see a clean safety profile, typically tested in two species (usually rodents and non-human primates), although the species may vary depending on the program.
Another critical factor in the go/no-go decision is the competitive landscape. We regularly review competitive intelligence to determine:
- Are there new entrants addressing the same indication?
- Do we still have a clear advantage?
- Can we differentiate our approach?
Because in cell and gene therapy, you’re talking about a high-cost, one-time intervention, and you have to ensure you’re truly addressing an unmet need—one that’s compelling enough to justify payer and insurance reimbursement.
What’s one area in early-stage development where companies often underestimate complexity or risk—and how do you tackle that at Sangamo?
You can have many ideas, right? But you really have to choose your programs with the end goal in mind. There are always technical challenges. For us, we had great zinc finger proteins—but initially, we didn’t have a way to deliver them to the brain. That was a major hurdle. It took us several years to develop our blood-brain barrier–penetrant capsid, and overcoming that challenge was key.
Sometimes, you simply don’t have all the tools at the outset to reach your destination. That means you have to make a decision—invest in building those tools, or pivot to a different program that may be more feasible in the near term.
Another important lesson is that perfection can be the enemy of progress. We have incredibly passionate and talented researchers who are always thinking about how to optimize—how to make something even better. And that’s great—but there’s a time and place for that. Improvements can be made in second-generation programs. But for a first-in-class therapy, we need to move quickly toward in vivo proof of concept.
Ultimately, in our field, the key inflection point is clinical proof of concept. That’s what creates real value—not just for the company, but for patients. So while it’s essential to understand the complexity and technical challenges of your work, it’s equally important to keep your focus on the goal: delivering transformational therapies that address unmet medical needs.
What advice would you give to scientists or program leaders hoping to advance into strategic executive roles in biotech?
I think what’s critical is having a deep understanding of all aspects of drug development—not working in silos. At Sangamo, we have program leads who act as “mini-CEOs” of their programs. That means they’re responsible and accountable for the overall program strategy and for leading their cross-functional teams as one cohesive unit. It’s not about research doing their part, development doing theirs, and tech ops doing theirs—it’s about everyone working together toward a shared goal: delivering a product that benefits patients.
What’s also important for leaders is to keep pushing their teams to be creative and innovative in how they accelerate development. As you know, the cell and gene therapy field evolves rapidly—every day there’s new science, emerging tools, or novel regulatory approaches. It’s not yet a fully mature field, which means there’s still a lot of opportunity to learn, adapt, and optimize.
So, staying on top of the latest developments, being open to alternative or parallel development paths, and thinking about ways to shorten timelines without compromising quality are essential. Program leads need to understand the entirety of drug development and be empowered to make or escalate key decisions. Of course, many decisions can be made within the team, but those that significantly impact timelines or budgets must be brought to executive leadership—with clear recommendations and rationale.
My advice is: don’t work in silos. Learn and appreciate the full drug development lifecycle. No one can develop a drug alone—it requires collaboration across research, nonclinical, clinical, regulatory, technical operations, and even general functions like IP, competitive intelligence, and business development. Being multifaceted and cross-functional is essential.
What trends in biotech R&D do you think will most impact how companies like Sangamo operate over the next decade?
There are several important aspects to consider. In the field of cell and gene therapy—often driven by small biotech companies—one of the biggest priorities is understanding how to reach clinical proof of concept as quickly as possible. One growing trend is the use of biomarkers to evaluate efficacy. We’ve seen several therapies receive accelerated approval based on biomarkers that are strongly linked to disease progression. In fact, regulatory agencies have recently accepted certain biomarkers as valid endpoints in specific diseases, which is a significant advancement.
This is critical because, in many cases, it can take years to demonstrate meaningful clinical outcomes. Yet patients are in urgent need—we can’t wait a decade to get a drug approved. Biomarkers can help us move much faster. In that context, the accelerated approval pathway is incredibly important. Having early and proactive discussions with regulators—whether it’s the FDA, EMA, MHRA, or other agencies—is essential. These agencies can be collaborative partners, and early engagement allows you to make agreements, present arguments, and even help shape the regulatory framework for your specific indication.
On the operational side, we’ve all seen how the field has been under pressure in recent years. It’s more important than ever to regularly assess your pipeline, focus on the most promising programs, and prioritize those with transformative potential. Cell and gene therapies are expensive to develop, and since they’re typically one-time treatments, the revenue model is very different from chronic therapies. You’re not generating recurring revenue over years—you rely on a single payment per patient.
This brings us to one of the biggest challenges facing the field today: reimbursement. The current system, especially in the U.S., is still not well equipped to handle high-impact, one-time therapies. Our reimbursement and insurance frameworks are outdated for this model, and meaningful change is needed at both the state and federal levels to support the continued innovation and accessibility of cell and gene therapies.
I strongly believe this field represents the future of medicine. The results we’ve seen across the industry have already been transformative for many patients, and it’s critical that we continue to encourage innovation. I truly believe cell and gene therapies have the potential to deliver cures—not only for rare diseases, but also for devastating conditions with high unmet medical needs.
This is why I’m so passionate about this work—and why I’m at Sangamo. The impact we can make on patients’ lives is profound, and I’m excited to be part of shaping what’s next.
