Inside Moderna’s Personalized Cancer Vaccine

**Stéphane Bancel** (0:00)
The first time there is a cancer vaccine working, the field has been doing that for 20 plus years, more than a thousand clinical trials that have all failed.

**Jorge Conde** (0:08)
What was different this time? What is it about mRNA technology that enables the immune system to learn in a way that other approaches were unable?

**Stéphane Bancel** (0:18)
We all have cancer cells all the time in our body. Our immune system is very well trained to basically notice those cancer cells very early and get rid of them. But if your cancer grows, then the question is, how can you reteach the immune system? We're going to basically take a biopsy of your tumor. We're going to read all the letters of its DNA. And then we're going to do the same things with the healthy cell of your body. And we're going to literally compare letter by letter, nucleotide by nucleotide. And then we're going to use an algorithm to identify which one of those mutations are the most relevant. And so when this is injected in your body, it teaches the immune system the signature of your cancer cell that it missed.

**Jorge Conde** (0:55)
What gets regulated here? Because every dose is different, so obviously every dose doesn't get approved.

**Stéphane Bancel** (1:00)
Basically, Jorge, what the FDA wants to know.

**SPEAKER_3** (1:04)
Before Moderna's mRNA platform helped produce a COVID vaccine, the company was already working toward another goal, using mRNA to fight cancer. A decade later, that bet has reached a major milestone.
A16z general partner Jorge Conde sits down with Moderna CEO, Stéphane Bancel, following positive phase three results from Moderna and Merck's individualized mRNA treatment for melanoma.
It's the culmination of a project Moderna has been working on for roughly a decade. Stéphane explains how Moderna takes a patient's tumor, sequences it against their healthy cells, identifies the mutations unique to that cancer, and uses that information to manufacture a personalized mRNA designed to teach the immune system what to attack. And because roughly 90% of the selected antigens differ from one patient to another, personalization isn't an edge case. It's fundamental to how the treatment works.
They also get into the extraordinary operational challenge behind this. How do you manufacture thousands of different medicines, one patient at a time, quickly and reliably enough to make personalized medicine work at scale? And finally, they look at where the platform could go next, from other cancers to rare genetic and autoimmune diseases.

**Jorge Conde** (2:20)
Hi, welcome to The a16z Podcast. I'm Jorge Conde, a general partner on The a16z Bio and Health Team. I am thrilled today to welcome back Moderna CEO Stéphane Bancel. For folks that have been long-time listeners may recall, Stéphane joined us on The a16z Podcast back in December of 2020, when we were talking about all of the work Moderna did to bring us the mRNA COVID vaccine. And at the time, if you can go back and listen to that episode, you'll hear how quickly Moderna was able to react to the existence of the virus, to analyze it, to essentially print a vaccine that would protect people against the COVID-19 vaccine and hence put us in a much better position with respect to the COVID pandemic. We titled that episode, The Machine That Made the Vaccine. And the reason why we're talking again today in August 2026, is because Moderna has put out news on a really big advancement on what they can do with mRNA technology when it comes to cancer.
And so I want to hand it over to you, Stéphane. Again, a very big welcome. Thank you for coming back. But maybe the place to start is let's lead with the news. Moderna and Merck announced earlier this month in August that you had conducted a phase 3 clinical trial in melanoma and have gotten very encouraging results.
So why don't I hand it over to you and tell us, what have you announced? What have you seen in this phase 3 trial? And then I do want to dig in into what Moderna is doing in cancer.

**Stéphane Bancel** (4:03)
Wonderful, so Jorge, thank you so much for having us back. We're very happy to be with you. So indeed, last week now, we shared the news with our colleagues at Merck that after working 10 years on individualized treatment against cancer using mRNA technology, that the phase 3 was positive. It's the first of many. It's the first time that there is an agent in melanoma that is better than Ketidra alone. So it's a big deal for patients, of course, with melanoma. It's the first time there is a cancer vaccine working. The field, as you know, has been doing that for 20 plus years, I think more than a thousand clinical trials that have all failed.