Cancer immunotherapy has transformed blood cancer treatment, but solid tumors remain difficult to treat. Existing CAR-T therapies remain expensive for patients and complex to manufacture, while their limited effectiveness against solid tumors restricts their clinical use.
Additionally, the need for more effective treatments is particularly urgent in ovarian cancer. The disease caused approximately 204,000 deaths worldwide in 2024, according to IARC’s GLOBOCAN estimates.
Australian biotech startup Cartherics is developing genetically engineered natural killer (NK) cells to tackle these challenges. The startup produces treatments from stem cells rather than individual patients’ immune cells. This approach reduces manufacturing costs to below $10,000 per dose. Its initial focus is ovarian cancer, with plans to expand into other diseases, including endometriosis.
GreyB spoke with Cartherics CEO Dr. Ian Nisbet to understand how the technology works, why NK cells could offer advantages over CAR-T therapies, and what it will take to make these treatments more affordable.
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This interview is part of our exclusive Scouted by GreyB series, where we explore emerging startups and the technologies they are developing to address major industry challenges.
“By using natural killer cells, we have that safety profile, we have more modes of killing.”
— Ian Nisbet
Dr. Ian Nisbet is the CEO and co-founder of Cartherics, with over 40 years of experience in pharmaceutical research, biotechnology, and drug development. He holds a bachelor’s degree in microbiology and biochemistry from the University of Melbourne and a PhD in molecular biology from Monash University. He also completed the Advanced Management Program at Melbourne Business School.
Before joining Cartherics, Dr. Nisbet held senior positions at CSL, Millennium Pharmaceuticals, and ChemGenex Pharmaceuticals. He led development teams responsible for two FDA-approved cancer drugs, Velcade and Synribo. His experience bringing cancer treatments from research into clinical use now guides Cartherics’ efforts to develop more accessible cell therapies.
Cartherics Is Developing Off-the-Shelf Immune Cell Therapies for Solid Tumors
Cartherics is an Australian biotechnology company developing genetically engineered immune cell treatments for cancer and other diseases. Its technology combines induced pluripotent stem cells (iPSCs), CRISPR-based gene editing, and chimeric antigen receptors (CARs) to produce natural killer cells designed to recognize and attack abnormal tissue.
Unlike conventional patient-specific CAR-T therapies, Cartherics’ platform is designed to manufacture large quantities of standardized immune cells from a renewable stem cell source. Its lead product targets TAG-72, a marker commonly found on ovarian cancer cells. A second program targets tissue factor, which the company is investigating for both cancer and endometriosis applications.
CAR-T therapies have already transformed blood cancer treatment. Why did you choose natural killer cells instead of T cells?
CAR-T cells have proven incredibly effective in certain blood cancers, particularly for patients who have exhausted other treatment options. However, T cells can be extremely aggressive. Their activity can trigger severe immune reactions, and some patients have experienced life-threatening side effects.
Natural killer cells offer a different balance. They are generally less aggressive and have shown encouraging safety profiles in clinical studies. What makes them particularly interesting is that they can naturally identify and destroy abnormal cells through several different mechanisms.
We enhance that ability by introducing a chimeric antigen receptor, or CAR, which helps the cells recognize a specific cancer marker. Unlike CAR-T cells, which rely heavily on their engineered receptor, CAR-NK cells retain their natural killing mechanisms. This means that even if cancer cells stop expressing the targeted marker, our NK cells may still be able to attack them through other pathways.
Solid tumors can suppress immune cells before they destroy the cancer. How are you engineering your NK cells to overcome this?
One of the biggest differences between blood cancers and solid tumors is the environment surrounding the cancer cells. Solid tumors, such as those found in the lungs, pancreas, or ovaries, create conditions that make it difficult for immune cells to remain active.
Cancer cells release signals that effectively switch off the immune cells trying to attack them. We are using genetic engineering to modify our natural killer cells so that they can resist some of these signals. We introduce those modifications at the stem cell stage, before converting the cells into natural killer cells.
The idea is to create immune cells that are more resistant to the tumor’s defenses than the cells naturally present in the body. If we can deliver large numbers of these enhanced cells into patients, we believe they could remain active and attack tumors more effectively. That is what we want to demonstrate in clinical studies.
Ovarian cancer and endometriosis are very different conditions. What made you select them as targets for the same technology?
We selected ovarian cancer first because it has a significant unmet medical need. Many patients are diagnosed at stage three or four, when treatment options are limited and survival rates are relatively low. We also identified a promising target called TAG-72, which our research indicates is expressed in approximately 90% of late-stage ovarian cancer cases.
Our interest in endometriosis developed from the similarities we observed between the two conditions. In ovarian cancer, we plan to deliver our NK cells into the peritoneal cavity, where cancerous tissue can develop. Endometriosis also involves abnormal tissue growth in this region, although it is not cancer. That suggested we might be able to apply a similar treatment approach.
We subsequently identified tissue factor as another promising target. It is widely expressed in endometriosis tissue and the blood vessels supporting its growth. Our plan is to establish safety in cancer patients first, where the acceptable risk is different, before considering trials in women with endometriosis.
Many women with endometriosis have already undergone hormonal treatments. Could those treatments affect the markers your therapy targets?
That’s an important question, and there isn’t enough research available to give a definitive answer yet. We know that tissue factor is strongly expressed in endometriosis, and we believe its expression is linked to the underlying biology of the disease. This suggests that the marker may remain present after other treatments, although that still needs to be confirmed.
We have also observed that TAG-72 is expressed in certain forms of advanced endometriosis. It may potentially increase as the disease progresses, but we are not currently developing our lead TAG-72 product specifically for this indication. Tissue factor remains our preferred target for endometriosis.
One of the broader challenges is that endometriosis remains poorly understood. There has been relatively little drug development focused on the condition, and many questions about its underlying biology remain unanswered. We hope our research will contribute to that knowledge, even as we investigate the possibility of a new treatment.
Your CAR-NK cells have shown promising results in laboratory studies. What evidence do you have that they will work in patients?
We have generated a substantial amount of data from laboratory experiments and animal models. These studies demonstrate that our engineered natural killer cells can effectively kill ovarian cancer cells and cells from other cancer types.
However, our specific products had not yet entered human testing at the time of our conversation. We therefore cannot say how they will behave in patients. What gives us additional confidence is research from other groups showing that unmodified natural killer cells can produce responses in ovarian cancer patients.
Our approach builds on that foundation by adding a receptor that targets TAG-72, along with genetic modifications intended to improve cell activity inside tumors. We believe those changes could improve the responses seen with ordinary NK cells, but the clinical trials will determine whether that expectation is correct.
CAR-T therapies are notoriously expensive. How much could your stem cell-based manufacturing approach reduce treatment costs?
Cost reduction was one of the fundamental reasons we developed this platform. Traditional CAR-T treatments require manufacturers to collect cells from each individual patient, modify them, grow them, and return them to that same patient. This is a complicated and expensive process.
We start with stem cells that can be grown continuously in the laboratory. From these, we can produce billions of genetically modified natural killer cells that could potentially treat multiple patients. Even at our initial clinical manufacturing scale, we estimate that our production costs are at least ten times lower than those of conventional patient-specific CAR-T cells.
Our longer-term target is to bring the manufacturing cost below approximately $10,000 per dose, compared with the 200,000–250,000 manufacturing cost estimates we discussed for conventional autologous CAR-T treatments. There are still significant expenses involved. A batch takes around 35 days to manufacture, and specialized facilities, equipment, and materials are costly. But we see opportunities to reduce those costs further as manufacturing improves.
The final selling price will depend on several factors beyond production costs. Nevertheless, we believe that making the cells much more affordably should ultimately allow us to offer treatments at a lower price and reach a broader patient population.
Developing a completely new cell therapy involves significant uncertainty. How do you approach the risk of clinical failure?
Drug development is inherently risky. It takes a long time, requires substantial investment, and many promising treatments ultimately fail. When you’re developing something that has never been tested in humans, you have to accept that the results may not match your expectations.
My experience has also shown me why taking those risks matters. I was fortunate to work on two drugs that eventually received approval, including Velcade for multiple myeloma. Having a patient tell you that a medicine you helped develop saved their life is an extraordinary experience. It reminds you why the difficult years of research are worthwhile.
For me, perseverance is one of the most important qualities in drug development. If a treatment fails, you need to understand what went wrong, learn from it, and decide what to do next. We believe cell therapies have an important place in treating cancer and other diseases, but finding the right modifications, targets, and applications will take time.
Even when a particular development program doesn’t succeed, the scientific knowledge gained can help advance the field. That is why we continue working on these technologies despite the uncertainty. The possibility of developing a treatment that changes patients’ lives makes the effort worthwhile.
Meet our Interviewer – Shabaz Khan, Marketing Manager at GreyB
Shabaz Khan, Marketing Manager
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