LIVE from the 2026 SITC Annual Meeting, ft. Dr. Ryan Sullivan

Dr. Patrick Hwu welcomes Dr. Ryan Sullivan, a medical oncologist at Massachusetts General Hospital, associate professor of medicine at Harvard Medical School and chair of the Society for Immunotherapy of Cancer’s (SITC) Annual Meeting Program Committee. A leading melanoma researcher, Dr. Sullivan discusses the latest advances in cancer immunotherapy and the emerging treatments offering new hope for patients.

Recorded at the 2026 SITC Annual Meeting in Phoenix, this special bonus episode explores some of the most promising research presented at the conference. Drs. Hwu and Sullivan discuss breakthroughs in personalized cancer vaccines, innovative bispecific therapies and advances in cell therapy, including approaches that could allow CAR T cells to be engineered directly inside the body. They also examine new strategies to reduce the toxicity of tumor-infiltrating lymphocyte (TIL) therapy and the potential of oncolytic viruses to stimulate immune responses against brain tumors.

Dr. Sullivan also reflects on his journey into immunology and how once-theoretical approaches are becoming increasingly viable treatment options. From cancer vaccines to next-generation cellular therapies, the conversation highlights the diversity of approaches shaping the future of immunotherapy and the potential to bring more effective treatments to patients.

Podcast Transcript

PATRICK HWU:

Welcome to ImmunoVerse, a podcast that brings the ever-expanding universe of immunotherapy to life through the voices of those advancing this groundbreaking field.

I’m Dr. Patrick Hwu, president and CEO of Moffitt Cancer Center. In each episode, I sit down with the pioneering experts who have shaped the past, present, and future of immunotherapy, uncovering breakthroughs, challenges, and the science driving this lifesaving innovation.

Today, we’re bringing you a special bonus episode, Best of SITC, from the Society for Immunotherapy of Cancer’s Annual Meeting in Phoenix.

With the conference still underway, we’re taking a closer look at some of the research being shared and what it could mean for the future of cancer treatment.

I’m pleased to welcome Dr. Ryan Sullivan, a medical oncologist at Massachusetts General Hospital and an associate professor of medicine at Harvard Medical School.

He serves as chair of SITC’s Annual Meeting Program Committee and a member of its Board of Directors, giving him a broad perspective on the science coming together at this year’s meeting.

Dr. Sullivan’s research focuses on developing new treatments for melanoma, bringing promising discoveries into clinical trials, and identifying biomarkers that help predict treatment response.

Today, he’ll help us explore some of the meeting’s notable findings, put early results into context, and discuss the questions these studies raise for the field.

Welcome to ImmunoVerse, Dr. Sullivan.

RYAN SULLIVAN:

Great. Thanks, Dr. Hwu. It’s a pleasure to be here.

PATRICK HWU:

That’s great. Well, tell me, how did you get into science in the first place?

RYAN SULLIVAN:

It just always seemed to be part of my life. My father was a physician, and I always was excited about the concept of applying science to patient care.

I think in a few summer programs, I loved astronomy, loved dinosaurs, and learning everything about the stars or the dead animals that are now fossils seemed like a really cool thing.

And then in school, science just popped. And so that’s how I got into science.

How I got into immunology is, I was sitting in our first year of medical school classes, and I was like, “I love this.”

We’re learning about the whole armamentarium that the body has to fight off invaders. We’ve got something for viruses, we’ve got something for worms, we’ve got something for bacteria, we’ve got something for all kinds of foreign invaders.

And then you start learning about, holy cow, our body can fight off cancer, too. And it just stuck.

PATRICK HWU:

Yeah. Thank God for our immune system, right? There are so many organisms attacking.

RYAN SULLIVAN:

Amazing. Yeah, totally amazing.

So that blew my mind. And I said, “I have to do that.”

In between my first and second year of medical school, I worked in a tumor vaccine lab at the University of Connecticut with a guy named B.J. Mukherjee.

I learned in a much more detailed way about the immune system and cytokines, the crosstalk between immune cells, and how that might lead to a better antitumor response.

And it was just amazing.

PATRICK HWU:

Well, thank you for being here today. And thank you for all you’re doing for SITC, both on the Board of Directors and really programming this large meeting with over 3,000 people and many abstracts.

It’s exciting what tumor immunology is bringing to cancer therapeutics. Now we’re saving more patients than ever.

So tell us, what’s most exciting this year?

RYAN SULLIVAN:

Yeah. You know, when we were planning the meeting this year, we were trying to figure out what we wanted to highlight.

And we knew that there was going to be some breaking news prior to the meeting about vaccines. We didn’t know what it was going to show.

And so I think we were really intentional about front-loading the meeting with both the Smalley, MD Memorial Award and Lectureship and Cathy Wu, who’s done pioneering work in tumor vaccines and personalized cancer vaccines.

And then for the Waldmann Plenary Session, we wanted to focus on cancer vaccines.

We were able to recruit this amazing group of people, including Vinod Balachandran from Memorial Sloan Kettering, who’s done really pioneering work with mRNA vaccination and pancreatic cancer.

Darryl Irvine from Scripps, who’s this amazing engineer who’s able to do all kinds of crazy things that help the immune system recognize cancer better.

So we were just ready to go.

And then when the data came out with intismeran, which is an mRNA vaccine that’s personalized, built from analyzing tumor DNA and the inherited DNA from patients, and then looking at which of the differences, the mutations, are expressed in the tumor, putting it through a black box that also includes the HLA of the patient, and then coming up with a product that you can use to augment adjuvant anti-PD-1 therapy for patients with melanoma.

That data was press-released, I think, in August, and was presented a couple of weeks ago at ESMO. It showed a positive study in a phase 3 trial with a tumor vaccine.

And we’re hoping that these sessions also continue to create a lot of excitement in the field and get people really excited about the fact that one of the oldest immunotherapies, vaccination, maybe the oldest, actually can help patients with cancer and prevent relapse in a setting where they were highly likely to relapse.

PATRICK HWU:

So cancer vaccines are the big news of this meeting, including the melanoma data.

We’re both melanoma doctors. So where do you see this being used now in your practice, in my practice, in the future, in the next year or two?

RYAN SULLIVAN:

Yeah, I think the data is really good.

The data was in patients with stage II melanoma and stage III melanoma, and some patients with stage IV melanoma who had their tumors resected.

I think anybody that’s had completed surgery for their melanoma and is at high risk of recurrence, that would be somebody I would use this approach with.

And that would include anybody with stage II melanoma, most people with stage III melanoma.

So I think there are a lot of people who can benefit from this.

There’s a lot of chatter about, well, it’s about as good as anti-PD-1 therapy if you give it in the neoadjuvant setting.

But most patients don’t have a neoadjuvant option.

They have surgery for a high-risk melanoma, and their lymph nodes are positive microscopically. They were never a candidate for that.

And so I think there are a lot of patients who can benefit from this.

And I think the plan would be, if available, we would seek to give this to as many people who are eligible for it.

PATRICK HWU:

So melanoma, a cancer of the skin which we treat, that’s caused in large part by mutations from the UV rays of the sun, sunburn, can then spread to the lymph nodes of the body.

And so when it spreads to the lymph nodes and there’s large lymph nodes, we will give immunotherapy right off the bat, even before the surgery.

But if it doesn’t look like it’s spread to the lymph nodes, and it’s in the skin, and you take out the skin area of malignancy, the primary site, we call it, and if there are microscopic tumor cells in the lymph nodes, at that point there’s a risk of the melanoma coming back.

So you think in that setting, we would probably be giving this personalized cancer vaccine?

RYAN SULLIVAN:

Exactly.

PATRICK HWU:

Yep. And to get this personalized cancer vaccine, we have to really sequence the tumor cells.

And sometimes it’s pretty microscopic. So how frequently can we actually get that sequencing done to personalize the vaccine?

RYAN SULLIVAN:

Yeah. In all the trials that have been done so far, it’s about 80% of patients.

So it’s not perfect.

I think one of the things that’s going to be critical for the rollout of this type of therapy is to figure out, are there standard operating procedures? Are there certain amounts of tumor that are going to be required?

It’s going to be really important for us, as medical oncologists or surgical oncologists, to work with our dermatopathologists to figure out which samples from patients will yield better RNA and DNA quality and quantity, sufficient enough to be able to move forward with the analysis and the production of the vaccine.

I think once you have the quality and the quantity, they can make a vaccine for almost everybody.

So that’s the good news.

It’s really going to be identifying the right patients based on careful consideration and discussion with our multidisciplinary teams.

PATRICK HWU:

So vaccines, both clinical trial results as well as innovative approaches to cancer vaccines. Big news at SITC.

RYAN SULLIVAN:

Big news.

PATRICK HWU:

Yeah. What other topics have been highlighted?

RYAN SULLIVAN:

Yeah. So there are some really cool things that are being developed in some clinical trial work.

There are these whole new types of therapies that are combining targeted treatments to augment the immune system in one molecule.

These often go by the phrase “bispecific molecules.”

Many of the bispecific molecules, which means they’re targeting two things, involve binding to something on the tumor and then having another part of the molecule that engages with the immune system.

I like to describe this to my patients as evil matchmaking, where you bring the tumor cell and the immune cell together, and then it leads to the destruction of the cancer cell.

Obviously, it’s not evil for the patient. It’s good for the patient, but bad for the cancer cell, which we’re all for.

So there are two presentations that were presented on Saturday.

One is looking at two different bispecific molecules.

So one molecule that targets a protein on prostate cancer cells and recruits immune cells. Another that targets a different protein on cancer cells and preferentially activates the immune system.

And so that combination of those two drugs in prostate cancer is being presented.

Really exciting that you can not just have one bispecific molecule, but a second bispecific molecule, combine them together, and hopefully lead to better outcomes.

So that’s one example.

There’s another example of two bispecific molecules.

One is an approved drug called tebentafusp, which we use for uveal melanoma patients who have metastatic disease.

And that molecule targets a protein on the melanoma cells.

There’s another protein that can be expressed on melanoma cells as well that can be targeted by a second such bispecific molecule.

And so we’re going to see data on that combination, which is pretty exciting.

You know, 10 years ago, we would have said, “I’m not sure you can do that. I don’t know if that approach is going to work.”

So many things have to go right. You’re just randomly grabbing immune cells. How do you know that’s going to grab the right immune cells, which will know how to kill the tumor?

And I think the answer is now, yeah, that stuff does work.

There are a few examples that are already being used in the clinic today for small cell lung cancer and melanoma.

And then why not combine them if you have two targets on the tumor and either one way or two ways of engaging the immune system? Maybe that will lead to better results.

And it looks like it does.

And so that’s a pretty cool thing to be able to highlight.

And that’s what SITC is about.

It’s novel immune therapies. It’s figuring out different ways, or slightly different ways, of bringing forward technology that is designed very specifically to elicit an effective immune response against cancer.

And to be able to go from 10 years ago of skepticism to 10 years later, being able to see these things being realized and then expanded upon in these combination trials, is pretty exciting.

And I’m really excited that that data is being presented here.

PATRICK HWU:

Well, there are also some interesting and exciting studies being presented along the lines of T cells, correct?

RYAN SULLIVAN:

Yeah. So there’s been this explosion of therapies that involve engineering, or not engineering, but modifying, or not modifying, but expanding people’s immune cells and then giving them back to help fight their cancer.

That T-cell product that we call TIL, tumor-infiltrating lymphocyte therapy.

There’s one therapy that’s approved by the FDA. It’s called lifileucel.

We’re going to see a presentation on Saturday by Lauren Banks from Memorial Sloan Kettering, looking not in melanoma, which is where the drug is approved currently, but in sarcoma, a cancer that we sort of gave up on in terms of trying to develop more effective immunotherapies, and seeing some really exciting results.

On some level, it’s hard to imagine I’m saying the words, but we are saying these words.

We actually believe that cancers that were previously not thought to be immune-responsive can respond to immune therapies.

And cell therapy is one such way that we can do that.

There are cell therapies called CAR T cells, where you take the immune cells out of the peripheral blood, so not from the tumor.

You modify them so that those T cells can recognize and then activate when they recognize what they’re designed to recognize once you put them back in the body.

Those have transformed the way we treat hematologic malignancies: leukemias, lymphomas, multiple myeloma.

We’re beginning to see that you can actually give, not even necessarily take out the cells, but you can give essentially the engineering aspect of the therapy just in the blood, in an infusion.

And they get into the cells, and they can then, in the body, do the same thing that you can do when you take out the cells, modify them, and give them back.

Obviously, that’s a much more efficient way of giving a cell therapy.

And the data that’s emerging from these is really exciting.

So we’re going to have sessions that are talking about that, the engineering involved in it, and we’ll see some abstracts on that as well.

And that’s called in vivo CAR T-cell therapy.

Really amazing stuff.

Again, something 10 years ago, we’d be lucky if we could actually do this and make better these boutique therapies that are being given to people.

And now it’s like, “Oh, we can just inject them with the stuff that makes the CAR T cells, and the body will take care of the rest.”

It’s amazing.

And so we’re going to see some stuff on that.

Really, really exciting to be a part of a meeting that’s highlighting these.

PATRICK HWU:

Yeah, I think that’s incredible that it’s having some effectiveness, giving the vectors themselves to the patient and transducing the T cells in the body itself. It’s remarkable that it’s starting to work.

RYAN SULLIVAN:

Yeah, it’s crazy. But it seems to work.

And that’s, I mean, it’s just awesome.

PATRICK HWU:

Talk about when a patient gets TIL therapy. They often have to get interleukin-2, which can be quite toxic.

Well, there is a study being presented where they’re giving acetazolamide, which is just a pill that you take when you actually get—

RYAN SULLIVAN:

Altitude sickness, right?

PATRICK HWU:

It’s a very benign medicine, and instead of the interleukin-

RYAN SULLIVAN:

So, yeah.

I think the highest compliment that I can give to scientific endeavors is cleverness.

And it’s a very clever way of getting around some of the toxicity that’s associated with these TIL therapies.

Instead of just doing the garden-variety, which sounds crazy because there’s a lot involved in making TIL, the way to manufacture TIL, you actually insert a receptor that functions kind of like IL-2, but instead of IL-2, it’s IL-15.

This receptor complex can be induced to activate by giving acetazolamide, which allows for sort of local release of IL-15 that binds the IL-15 receptor, activates it, and leads to expansion of these T cells.

Another cell therapy, this novel twist, you get to avoid giving this interleukin-2, which is a very toxic molecule.

That’s the T-cell-activating agent that we use typically for standard-of-care TIL.

And another product that can really help our patients with, in this case, melanoma.

But there’s no reason to think that this is just a melanoma drug.

This is a cell therapy drug that probably can be used for a lot of different types of malignancies.

PATRICK HWU:

I saw another study being presented about a virus for brain tumors.

RYAN SULLIVAN:

Yeah. So what’s interesting about this is it’s an adenovirus.

The viruses that have been used to kill cancer cells so far, many of them are herpes viruses.

But this is an adenovirus, a virus that can cause the common cold.

What seems really interesting about this study is that it seems to induce structures in the tumors that can better coordinate an immune response.

And so there’s been a lot of effort looking at brain tumors.

Many years ago, there was this very hyped-up polio virus study that was on 60 Minutes and got everybody really excited.

I don’t know about you, but every time I was in clinic talking to a patient about whatever, it came back to, “When’s the polio virus going to be used for my melanoma?”

And so brain tumors have been a focus for these types of therapies.

But what’s really cool is that you’re generating these structures in the brain tumor itself that then can help coordinate a more effective immune response.

That, to me, is a pretty wild thing.

It’s getting in all the right elements of the immune system to lead to a more effective response and tumor control.

I mean, ultimately, that’s all we’re trying to do with any immune therapy.

And the fact that this virus can do that, and does this in this very specific way, is really cool.

PATRICK HWU:

I mean, in the end, we just want the immune system to kill cancer, right? And there are several paths.

RYAN SULLIVAN:

Exactly.

PATRICK HWU:

You can put a virus into the tumor to try to generate the immune cells.

You can give a personalized cancer vaccine.

You can take T cells out of the body, put genes in, and give them back.

You can try to modify T cells directly.

RYAN SULLIVAN:

Directly in the body.

PATRICK HWU:

Yeah. It’s really exciting that there’s such a diversity of approaches all being presented here.

RYAN SULLIVAN:

Exactly, exactly.

PATRICK HWU:

At the annual meeting.

We want to thank our guest, Dr. Ryan Sullivan, for joining us today.

And thank you for going on this journey with us through the ever-expanding universe of immunotherapy.