GEOFF BENNETT: A medical breakthrough in the fight against pancreatic cancer is showing promising results after decades of research.

The experimental drug taken once a day extends patients' lives by slowing the progression of one of the deadliest cancers.

Stephanie Sy has more.

STEPHANIE SY: Geoff, it's called daraxonrasib.

And, put simply, it targets mutations of the KRAS gene, a common driver of pancreatic cancer that chemists viewed for a long time as undruggable.

Pancreatic cancer is expected to kill more than 52,000 Americans this year.

It's often diagnosed after it's already spread, putting the five-year overall survival rate at a meager 13 percent.

For most advanced patients, there's no cure.

And standard treatment has been chemotherapy.

Experts say that could be about to change.

For more on what this means for patients and the future of cancer treatment, I'm joined by Dr.

Rachna Shroff, associate director of clinical investigations at the University of Arizona Comprehensive Cancer Center.

Dr.

Shroff, this is hopeful, to say the least.

And before we get into the details, I imagine you have treated and lost many pancreatic cancer patients over the years.

I lost my own mother to the disease very quickly a few years ago.

What was your reaction when the results were read to the room over the weekend?

DR.

RACHNA SHROFF, University of Arizona Cancer Center: You know, I think, like you said, this was a monumental day in the treatment of pancreatic cancer.

I have been using the word game changer, and that is not a word that we use lightly when it comes to treating this disease.

And the honest truth is, it was tears, tears of joy, 16 years of treating this disease, and, like you said, countless lives lost to this horrible, horrible cancer.

And so to see the results and to be in that room with a number of people who have that same drive to kind of improve cancer outcomes for patients, it was an incredibly emotional moment.

STEPHANIE SY: The studies participants were looking for a Hail Mary.

They'd all undergone at least one round of chemo, from what I understand.

And the results showed those put on this new drug lived an average of 13 months, compared to those who lived only about six months without it.

How significant is that, Dr.

Shroff, in the world of oncology?

DR.

RACHNA SHROFF: You know, I would say that having the ability to have a pill double survival in patients who have already had one prior type of treatment for pancreatic cancer and have stage four disease is so far unprecedented.

We have not ever seen a doubling of survival when it comes to treating this disease.

And that is incredibly impactful, of course, just from a numbers sake, but also is so meaningful to patients who are hopefully going to see more milestones, more important moments in their life.

STEPHANIE SY: This is the same experimental drug that former Senator Ben Sasse has been on since his pancreatic cancer diagnosis.

Here's what he said to "60 Minutes" Scott Pelley in April about why he's still alive.

FMR.

SEN.

BEN SASSE (R-NE): Let's go with providence, prayer and a miracle drug.

In mid-December, I was given a three-to-four-month life expectancy.

I am on extended time already.

I have much, much less pain than I had four months ago when I was diagnosed, and I have a massive 76 percent reduction in tumor volume over the last four months.

STEPHANIE SY: Now, we should also say that Sasse said to a different journalist that the side effects have been pretty nasty, that his skin bleeds and sometimes feels nuclear, were his words, Dr.

Shroff.

But what else should people know about side effects of this drug and who it can and can't help?

DR.

RACHNA SHROFF: Well, so far, from the results that we have seen in terms of who it can and can't help, we think it really is a drug that should be offered to all patients who have had one prior line of chemotherapy.

While we recognize that this drug specifically targets the KRAS mutation -- or the KRAS pathway, rather, over 90 percent of pancreatic cancer patients have KRAS mutations.

And this study included all comers.

It was -- seems to work regardless of KRAS mutation status.

And so it really hopefully will become the standard of care for all patients after one prior line of chemotherapy.

Now, as you mentioned, things to know, yes, with every drug comes side effects and toxicities.

But I will say that there is a learning curve for all of these drugs.

And all of us who -- once we get our hands around it, once we work with some of our multidisciplinary colleagues, for instance, with the rash, working closely with our dermatologists, we're learning.

We're learning how to be preemptive and prophylactic about trying to prevent such severe side effects that the patient's quality of life is affected.

For the rash, avoiding sunlight, using oral antibiotics and topical steroids, I mean, those things seem to be helping, seem to be mitigating the rash.

And I think the other thing I will say is, is that, when you look at the study, only a small percentage of patients actually discontinued taking the drug because of side effects.

And so I think, if we're able to provide clinically meaningful improvements for our patients, as long as we learn how to manage side effects, we can hopefully handle those trade-offs.

STEPHANIE SY: And that KRAS pathway, those mutations, I understand, are also involved in other cancers, including those of the colon and the lung.

So what potential does this drug hold for those patients?

DR.

RACHNA SHROFF: Well, I literally keep saying that the RAS revolution is here.

This has been historically undruggable.

This has been the Holy Grail for cancer, because, like you mentioned, KRAS mutations are ubiquitous.

We see them across all kinds of different tumor types.

And so now, now that we have proof of principle, that we know that targeting this pathway provides meaningful outcomes and improvements in patients with pancreatic cancer, the next obvious question is, is, what can this drug and other RAS inhibitors do?

And we have other KRAS inhibitors that are already available in colon cancer and lung cancer.

So now we're kind of in this next wave, where we're going to see what daraxonrasib can do in colorectal cancer, lung cancer, but a number of other cancers in which KRAS mutations exist.

And this is just the first of many drugs and many more trials that will hopefully answer those questions.

STEPHANIE SY: And we should note the FDA has granted some patients early access to the drug while the company seeks expedited approval from the agency.

That is Dr.

Rachna Shroff with the University of Arizona.

Thank you.

DR.

RACHNA SHROFF: Thank you.