Targeting Drug Tolerant Persister State in Lung Cancer

February 21, 2024

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Yale Cancer Center Grand Rounds | February 16, 2024

Presented by: Dr. Pasi Jänne

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00:00So I'm Roy Herbst,
00:01Deputy Director here at the Cancer Center,
00:04and it's really my honor to
00:06introduce the Cal Brazy Lecture.
00:09And this year you'll you'll
00:10meet Doctor Pasiani,
00:11who will be introduced by our lung program,
00:13scientific leader Katie Poletti and
00:15clinical leader Sarah Goldberg.
00:17But first, I just want to
00:18say a word about Paul
00:22Paul. Cal Brazy is often referred to as
00:24the father of oncology and its influence
00:26here at Yale Cancer Center remains a
00:28former faculty member at Yale School
00:30of Medicine who was internationally
00:32recognized as an authority on the
00:34pharmacology of anti cancer agents.
00:36Doctor Calabrazi serves as director
00:38of the Yale Cancer Center's Advisory
00:40Board until 2003 and we honor him
00:42with a conference room WW2 O 8
00:45where his picture hangs and I bet
00:47almost everyone here has visited.
00:49You can see here's the conference room
00:51shown on the slide with a beautiful
00:53portrait of Paul and all the lecturers,
00:55the 13 who have given this lecture over
00:58the last 14 or 15 years have shown and
01:00Doctor Yanni's plaque is already there
01:02and you can see the outside of the room.
01:04So if you haven't been to the room,
01:05go visit.
01:05We were just there and it was just
01:07wonderful to be with the Cal Brazy
01:09family and I welcome them all here
01:11today and to take some photos.
01:13This is a list of the lecturers.
01:15This is a very important lecture.
01:17You know, Paul was you know who
01:19who here has AK12 award?
01:21Do we have any of our K12 awardees here?
01:24They'll be.
01:25Yep, Yep so. So we have.
01:27So K12 is the Calabresi award.
01:30Paul was all about mentorship,
01:31teaching, taking care of the patient.
01:34He was both a scientist and a clinician.
01:37The the true what we used to
01:38call the three legged stool.
01:40So we try to invite people to these lectures
01:43and you can see the list of lecturers.
01:45And the very first one was Eddie Chu,
01:47also a mentee of Paul.
01:48And last year we had Steven Rosenberg.
01:53And here are just some photos over the years.
01:56It's very special lectureship for me
01:58because I actually met Paul 44 years ago.
02:01And how did I meet Paul?
02:03I have a picture,
02:04I can only find 2 pictures on the left,
02:07that's Paul behind his wife Seal.
02:08And that's me at my friend
02:10Peter Calabresi's wedding,
02:11the only picture Janice could find for me.
02:14But Paul was mentoring me and how
02:16to walk and stand stand up straight.
02:18And then on the right Paul took this picture.
02:21There's another picture with
02:22Paul but I couldn't find it.
02:23But that's Peter and I just a few
02:25years ago probably around 1983.
02:27You can see I'm I'm drinking a tab but,
02:30but, but but Paul was a mentor
02:32to me as to so many.
02:34That's always so special
02:35for me to have this lecture.
02:36And here we have Paul's
02:38brother Guido in the audience.
02:40His wife Ann was with us last night.
02:42His sons Peter and Steven.
02:45His daughter Janice Mimi,
02:47who is Steven's wife.
02:48So it's just wonderful to have
02:50the Calabrazi family here.
02:52But now to introduce our guest of the day,
02:54our speaker,
02:55I'm going to invite Sarah Goldberg and
02:56Katie Paletti to introduce Doctor Yanni.
03:00Good
03:06morning everyone.
03:07So this is really so such so wonderful
03:11to see everyone here and to meet and
03:13get to know the the Calabrazi family.
03:15But right now my my job is
03:17to introduce our speaker.
03:18So it is my absolute honor to
03:20introduce my colleague and friend,
03:22Doctor Pasiani as our guest lecturer for
03:24the Paul Calabresi Memorial Lecture Series.
03:27Doctor Yanni earned his MD as well as PhD
03:30degrees from the University of Pennsylvania.
03:32He then completed postgraduate training
03:34in internal medicine at Brigham and
03:37Women's Hospital and in Medical Oncology
03:39at Dana Farber Cancer Institute.
03:40He's currently the director of the
03:42Lowe Center for Thoracic Oncology and
03:44the scientific director of the Belfer
03:46Center for Applied Cancer Science.
03:48And he's also professor of Medicine
03:50at Harvard Medical School and
03:51the David M Livingston,
03:52MD Chair at Dana Farber.
03:55So it was at Dana Farber that I
03:56first met posse when I was a fellow.
03:58It was several years ago now as we
04:00were reminiscing about last night,
04:01I worked in his clinic and still now,
04:03you know as we both see patients
04:05with lung cancer,
04:06we we sometimes still share patients.
04:08And I can personally attest that he
04:10really is a fantastic oncologist who goes
04:13above and beyond for every single patient.
04:15So I'm going to now turn over to
04:17to Katie Politi to tell you a bit
04:19about Doctor Yanni's remarkable
04:20scientific contributions and PASI,
04:22I'm really looking forward to your lecture.
04:25Thank you, Sarah.
04:27Bon giorno E benvenuti attuti specialmente
04:30a la familia calabresi E aldotor pasi Yanni.
04:35As I said,
04:36good morning and welcome to everybody
04:39and especially to the Calabrese
04:42family and to Doctor Pasiyani Today.
04:45The advances in lung cancer treatment
04:47over the past 20 years have been
04:50remarkable and are contributing to
04:52a reduction in lung cancer deaths
04:54that we've seen in recent years.
04:57Doctor Yanni's research has played a
04:59central and critical role in contributing
05:02to the better outcomes for patients
05:04with lung cancer that we see today.
05:07His main research interests include
05:10studying the therapeutic relevance of
05:12oncogenic alterations in lung cancer.
05:14He was one of the Co discoverers of
05:17epidermal growth factor mutations
05:19in lung cancer and has pioneered
05:21the development of therapeutic
05:23strategies for patients with EGF
05:25receptor mutant lung cancer.
05:27His lab based and clinical research has
05:30also focused on other oncogenic driver
05:33subsets like those for those patients
05:36whose tumors harbor K Ras mutations.
05:38As you will see today,
05:40Doctor Yanni's laboratory research is
05:42at the forefront of addressing major
05:44challenges in lung cancer and sets
05:46the stage for advancing approaches for
05:49clinical treatment of the disease.
05:51Thank you Pasi for being here today.
05:53It's a pleasure to have you here
05:55for this lecture.
05:59We're going to take a picture
06:01with a both Reef before
06:02we start because and for inviting
06:04child raising family to come up.
06:06I'm also going to ask Lori Pickens,
06:07our Senior Vice President from Smile,
06:09to join us and we'll take the obligate
06:12picture that will be in direct
06:14connect and we're how do you want us?
06:29How was he going to do that?
06:30So why have to come? The
06:35screen, by
06:39the
06:42way, went to a shoe up.
06:50What invited speaker knows they
06:52only get 15 minutes to clock,
06:54but we will have.
06:54By the way, at the end,
06:55we're having mentorship testing.
06:56With any training you would like to
06:59say we're going to have all the images.
07:02Could we kill this just for a second?
07:04Just for a quick second? Sure. Thanks.
07:23Good luck at lunch.
07:29Thank you so much. Thank you. I'll
07:36put it over here.
07:46Thank you for those wonderful
07:49introductions and thank you Roy and
07:51entire team for inviting me here.
07:54And thank you for the Calabrese family.
07:56It was lovely to meet all of you yesterday
08:00at dinner and and and and today as well.
08:04So I will focus my lecture today on
08:11on a specific area of lung Cancer
08:15Research that we call drug tolerant
08:19persisters and you'll see what
08:21that all means in a few moments.
08:24These are my disclosures.
08:25I work with lots of companies
08:28to try to develop new therapies
08:30and hence the disclosures. So as
08:36Doctor Goldberg mentioned,
08:38lung cancer therapies have changed
08:42quite a bit and we think of lung cancer,
08:44especially lung adenocarcinoma,
08:45which is the most common form of
08:48lung cancer today as as a cancer that
08:52harbors potentially targetable genetic
08:55alterations shown in this pie chart.
08:59And if we actually look at what
09:03has been approved as therapies
09:06for these different alterations,
09:08we actually have a large number of
09:11therapies and more coming all the time
09:13approved for specific subsets of lung cancer.
09:16And so when we see patients in the clinic,
09:19one of our first questions is to try
09:21to understand does the cancer in that
09:23individual harbor one of these genetic
09:25alterations that we could then use one
09:26of the therapies on the right hand
09:29side or enroll that patient into a
09:31clinical trial that may be evaluating a
09:33new therapy or a therapeutic combination.
09:35And the therapies are successful.
09:39However, they still don't cure
09:43patients with advanced lung cancer.
09:46They're better than than what we
09:49would have had 2025 years ago,
09:52which is chemotherapy,
09:53but we still need to continue to do better.
09:57And So what typically happens,
09:58and this is an example of a patient
10:01with a lung cancer and he's treated
10:03with a targeted therapy and you can see
10:06almost all of the cancer disappears,
10:09but then it ultimately comes back.
10:12And what I'll focus my discussion today
10:14and what my lab has focused a lot is
10:17trying to understand why does it almost,
10:20almost completely disappears,
10:23but not completely disappear.
10:26And if we made this sort of
10:29intermediate state completely disappear,
10:32would our therapies be more effective?
10:36So let's look at it at a kind
10:39of A at this level.
10:41So,
10:42so example of a cancer we call this
10:44this sort of intermediate state the the
10:47persistor state or the drug tolerant
10:49persistor state out of which cancer
10:52various resistance mechanisms that we
10:54can detect clinically ultimately arise.
10:57Sometimes resistance mechanisms
10:59can pre-existing cancers and when
11:01you treat them with therapies they
11:04can out outgrow it and and and and
11:07develop resistance in that way.
11:08But this is definitely as as shown
11:11in those scans before happens as
11:13well and so how,
11:14how,
11:14how can we do better well we can
11:16develop therapies that are more
11:18effective at this initial therapy
11:20stage to eliminate this intermediate
11:23state or we can treat or figure out
11:26what make what's unique about this
11:29intermediate state and how could
11:31we eliminate it and ultimately
11:34delay or prevent resistance.
11:37So one and and and as as as as you
11:42heard from the introduction, I,
11:43I focus on EGFR mutant lung cancer,
11:45which in that pie chart is not
11:48quite the biggest,
11:49sort of the second biggest piece of the pie.
11:51And we were involved in that initial
11:54discovery and have subsequently tried
11:56to develop therapies for patients who
11:59are treated with EGFR inhibitors.
12:01And one of the things that we're
12:04recently involved in was asking
12:06can we use another therapy such
12:09as chemotherapy that we
12:12commonly use in lung cancer in
12:13combination with an EGFR inhibitor.
12:15And would that in fact lead to
12:18a better outcome for patients
12:20compared to an EGFR inhibitor alone.
12:24And that could be because it's
12:26more effective initially or it
12:28impacts this intermediate state.
12:32And so this is a clinical trial that
12:34those of you who treat lung cancer
12:36patients are probably familiar with
12:37called the FLORA two trial where
12:40the standard of care EGF inhibitor
12:42ASA mertnib also known as Tagrisso
12:45was combined with chemotherapy
12:47compared to the ASA mertnib alone.
12:49And patients got combination chemotherapy
12:52and then followed by maintenance
12:55chemotherapy and and ASA mertnib.
12:58And this trial turned out to
13:00be a positive in in terms of
13:03progression free survival sort of
13:05delaying the likelihood of
13:10recurrence from or disease growth from
13:15lung cancer significantly depending
13:17on how how it was looked at by the
13:20investigators or by blinded review.
13:23It delays that by about nine months which
13:27which has clinical implications as well.
13:31It was especially effective in patients
13:33who whose cancer had metastasized
13:36to the brain this this difference
13:38is larger but even in patients
13:40who where that wasn't the case,
13:42it was effective.
13:43And if we look at the common
13:45types of EGFR mutations about the
13:47of the common ones about 50% are
13:49these Exxon 19 deletions and 50%
13:51are these Li 58 arm mutations.
13:53And in both cases chemotherapy improved
13:56the outcome of of of of the patients.
14:02It's it's too early to know whether
14:06this improvement translates
14:08into patients living longer.
14:10We'll hopefully have some updates
14:12later on this year on on that.
14:14But it did delay the what we call
14:17the 2nd progression free survival.
14:19So the time
14:23of so patients who got chemotherapy
14:25and an EGFR inhibitor first even if
14:28they got subsequent therapy it's
14:31still that was still effective.
14:34They they had a longer durability
14:37of benefit than if they just
14:40started the EGFR inhibitor.
14:42Now if we look at kind of trying
14:44to understand what is what is
14:47chemotherapy doing now it turns out
14:49that the this is the EGFR inhibitor
14:51alone and this is chemotherapy,
14:53these look very similar.
14:54This is, these are all individual
14:56patients and the degree or or so
14:59this is what we call a waterfall
15:01plot and these are all patients were
15:03measuring their tumor shrinkage.
15:05And what was maybe disappointing
15:09is that even with the addition of
15:12chemotherapy the the maximum or
15:16median best tumor shrinkage was
15:1950% in the EGFR inhibitor and only
15:2352.6% when you added chemotherapy.
15:26However,
15:27the durability of that shrinkage
15:29was much longer,
15:31about nine months longer if you
15:33had chemotherapy compared to the
15:35EGFR inhibited by itself.
15:37But it still means that there are
15:39cancer cells that are able to
15:42survive despite EGFR inhibition and
15:44and and and this is an area that we
15:48have focused pre clinically quite
15:49a bit and asked the question what
15:52sort of dictates the dichotomy of
15:54a of a of a of a cancer cell from
15:57dying versus surviving these cancers
16:00that have these EGFR mutations.
16:01This represents a cancer and
16:03these are individual cells.
16:04All of the individual cells
16:05have the EGFR mutation.
16:07So it's not like the ones that survive
16:09don't have the EGFR alteration,
16:10they do but they figure out ways
16:13to survive whereas others die.
16:14And several years ago we we
16:19recognize that one of the downstream
16:22pathways from EGFR map,
16:23kinase pathway are here as measured
16:26here by phosphorylation of URC is
16:29turned here it's on here it's off but
16:32within a few days it comes back on
16:34and if you block this pathway with
16:37a a MEC inhibitor here trimetinib,
16:39you can prevent that from happening.
16:42So why is that important?
16:43Well,
16:44the way EGFR inhibitors cause cancer
16:47cells to die is they down regulate
16:50this pathway as I've shown here that
16:53bath that leads to up regulation
16:56of a proipoptotic protein called
16:58BIM and then leads to cell death.
17:00And so now EGFR inhibition is decoupled
17:03from down regulating of this pathway.
17:05Now you've provided a a way
17:07for the cells to survive,
17:09turn this pathway on and and survive.
17:14And so here we can block it with a
17:17drug trimetinib, our MEC inhibitor.
17:19And we're trying to evaluate this in
17:22the clinic by doing a clinical trial
17:24combining an EGFR inhibitor here
17:26with a MEC inhibitor called solumettinib.
17:29And here we have to give it
17:32intermittently 4 days on,
17:34three days off because when these
17:35drugs are given by themselves,
17:37they have side effects,
17:39typically skin side effects and
17:40fevers and other side effects.
17:42And so we can't give both the EGFR
17:45inhibitor and the MEC inhibitor every day.
17:48Now whether this intermittent
17:50schedule achieves the same biologic
17:52outcome that we saw in the laboratory
17:56setting remains to be seen.
17:59Now despite doing those two therapies,
18:03if we look at cells under the microscope,
18:07they're still surviving cells
18:11even when we add those
18:13two combinations together.
18:14And if we analyze the cells that
18:16after one day of giving the drugs
18:17or 21 days after giving the drugs,
18:19we can see that all of the sort
18:21of EGFR and pathways are turned
18:23off including ERC because we're
18:25using that the MEC inhibitor here.
18:27If you withdraw those,
18:29if you then wash out the drugs,
18:31the cancer actually regrow regrows
18:33that we call rebound cells and all
18:36of those pathways are once again on.
18:39And so we had wondered how is
18:44it that they survive and they
18:47survive through up regulating
18:49another signaling pathway called
18:51the Hippo signaling pathway,
18:53namely a protein called Yap that
18:58normally when it's turned on or
19:02up regulated which happens in
19:03response to EGFR and MEC inhibition,
19:06it turns off the expression of A
19:10pro apoptotic sensitizer called BMF.
19:13And so if you now block this
19:15in any way genetically deleted
19:17or use drugs against this,
19:20you now up regulate this protein.
19:22It can release more of the apoptotic
19:26proteins namely BIM from anti
19:28apoptotic proteins and it can
19:31shift cell survival to cell death.
19:33And so that's another.
19:35So it's basically another counter
19:37regulatory mechanism by which
19:38cancer is used to survive.
19:40And this is just to prove that you
19:43actually need if you if you use
19:45genetic tools to knock out this BMF,
19:47you don't see the the the increased
19:50cell death here compared to if
19:52it's if it's not knocked out.
19:54And the good thing is there are now
19:56companies that make TEED inhibitors.
19:59This Yap protein interacts with
20:02another protein called TEED and
20:03there are multiple companies that
20:05are making these inhibitors and
20:07if we use these inhibitors.
20:08Here if we measure cell death in red,
20:10when we add one of these inhibitors,
20:12they increase cell death from
20:13blue to red and we hope that this
20:16is clinically meaningful.
20:17They're being mostly tested in
20:20initially in malignant mesothelioma,
20:22but they there are hopes that
20:25these will move towards testing
20:28in in lung cancers as well.
20:30So I mentioned the two kind
20:33of regulatory pathways.
20:34We then wanted to ask another
20:36question by studying this state and
20:38ask is there something that we can
20:40you know if we these are to enhance
20:42the initial effect of the therapies.
20:44I'll shift to talking about this
20:47cell state and ask are these are
20:50the unique vulnerabilities within
20:51this actual cell state.
20:53And when we did this prior study
20:55where we
21:00found this Yap teed pathway,
21:02we recognize that the cells that
21:05survive in after a inhibition with
21:07an EGFR inhibitor or any other
21:09inhibitor in the right genetic context,
21:12they have features of cellular senescence,
21:16so aging cells and it it doesn't
21:19matter how you characterize them,
21:21they all have this is a,
21:23they're often they stain blue and
21:25this beta galactosidase stain
21:26and they have other features that
21:28are all found in these cells.
21:30Now it's not true cellular senescence
21:32because true senescence is irreversible
21:35unfortunately as all of us are aging.
21:38But this is a reversible state
21:40because as I mentioned earlier
21:41if you take the drugs off,
21:42the cancer cells will start to to grow.
21:45And and there is a whole field
21:48of developing drugs trying to
21:51treat senescent cells and they're
21:54often referred to as Senalytics.
21:57And what we so we wanted to do is
22:01first treat our cancer cells with
22:04an EGFR inhibitor and then treat him
22:07with another drug to ask can we in
22:10this red example can we find drugs
22:13that would specifically eliminate
22:15or be toxic to those cells that are
22:18in this state And and when we look
22:20through and and screened all of them,
22:23the ones that
22:26scored in the top are inhibitors of BCLXL
22:32which is an anti apoptotic protein.
22:37So by inhibiting that you can again
22:40shift cells more to dying as opposed
22:43to surviving and this is enriched
22:46in the in the senescent state.
22:51So if that's true
22:52then we should be able to show that
22:54experimentally and so we first did this
22:56experiment where we took mice that have a
23:00carry a xenograft of an EGFR mutant cells.
23:02We treated them with a control or
23:05with the EGFR and MEC inhibitor
23:07combination for three weeks and after
23:09three weeks we split half the mice
23:11to continue the EGFR MEC inhibitor or
23:14added a BCLXL inhibitor Nabita Clex.
23:16And then we treated for another three weeks
23:20and then we stopped all the drug treatments.
23:22And we asked is there is there a
23:26difference in growth regrowth of the of
23:28the cancer in the in the model that just
23:31got the EGFR MEC inhibitor compared to
23:33the one that got the BCLXL inhibitor.
23:36Because if we if if if our hypothesis
23:39is correct at this state that persistent
23:42state has been established and if
23:43they're sensitive to the nevita clax,
23:45we should eliminate more of the
23:47cells and then it should delay the
23:50regrowth of the tumor.
23:52And it does a little bit in green
23:54here although you could argue that
23:56this is probably pretty marginal.
23:58This is so the treatment,
23:59this is the day day 42 when we withdraw
24:02the the drugs and then compare growth.
24:05And here if you look at the
24:07individual animals,
24:08here's the the three drug combination,
24:10you can see that most of them still
24:12grow back although there are some
24:15that are completely eliminated.
24:17So we were wondering why may that be
24:20the the case and one possibility is,
24:23are we delivering the drugs to
24:26the to these persistent cells in
24:28in an efficient manner.
24:30And to get at that problem,
24:33we've worked with AbbVie,
24:35A pharmaceutical company that has
24:38developed an antibody against EGFR
24:40that's coupled to a BCLXL inhibitor.
24:44So this is a more of a targeted
24:46called an antibody drug conjugate.
24:48So it's a more targeted way of
24:51delivering the BCLXL inhibitor
24:52specifically to cells that express
24:55EGFR like the cancer cells that we're
24:58interested in And it and that has
25:00the advantage of avoiding potential
25:02systemic toxicities because if you
25:04just give the inhibitor by itself,
25:05one of the toxicities that's been
25:07seen in the clinic is thrombocytopenia
25:09or lowering of platelet counts
25:11because this protein is important
25:13for maturation of the platelets.
25:14And so if you give the drugs will there
25:17go to the tumor and to the bone marrow,
25:19you'll start to see patients
25:21platelet counts decrease.
25:24And this is just to show that in from ADVI,
25:27if they use a small molecule inhibitor,
25:31here's normal platelets, they go down.
25:33But if he uses antibody drug conjugate
25:35since the this is not cleaved normally
25:38except when it's internalized into the cell,
25:40you don't see that much
25:42of A platelet reduction.
25:46So and in ABB Vie's experiments
25:48when they've done given the EGFR
25:51inhibitor together with this antibody
25:53drug conjugate from the beginning,
25:56they can certainly delay the
25:58regrowth of cancer cancers in
26:00in these two different models.
26:02But that wasn't exactly the
26:03question that we were after.
26:04We were after this question,
26:05what happens in that persistent state.
26:07So we kind of redid that experiment here
26:09using the EGFR inhibitor alone where
26:12we then after 21 days half the mice
26:15will continue the EGFR inhibitor alone,
26:17half the mice will continue the
26:19EGFR inhibitor and get this e.g.
26:22FRBCLXL antibody drug conjugate for
26:24another three weeks and then we
26:26withdraw the drugs and follow outgrowth
26:29and here we see a much more dramatic
26:32difference and green is the the,
26:34the, the the double combination.
26:36You can see that here individual animals.
26:38So it's much more impressive than than
26:41the than using the nevitoclax alone and
26:44the and the animals tolerate it quite well.
26:48There are some some over
26:50long periods of time.
26:52This is like you know six months later
26:55we can look at the we can look at the,
26:58the,
26:58the,
26:58the animals and not all of them are cured.
27:01Some of them do regrow and we
27:03can detect the regrowth by using
27:05antibodies that specifically detect
27:06the mutiny GFR protein.
27:10Sometimes we see immune infiltrates
27:14and if he if you if we compare.
27:16So we can cure some of the animals
27:18with the EGFR inhibitor alone,
27:20but we can cure many more
27:21when we add this other agent.
27:24In the middle of treatment is
27:28another model that kind of
27:30shows the same same phenomenon.
27:32Unfortunately,
27:32they also do start to regrow
27:36after a period of time and so.
27:41So we see that some mice are cured,
27:42others are not and that could be for
27:45lots of reasons, it's a duration of
27:47treatment important in the clinic.
27:48We would typically continue a second
27:50therapy for much longer periods of time
27:52than we did in the animal experiment.
27:54And of course there are other proteins,
27:57other antipoptotic proteins that
28:00can sort of compensate for BCLXL
28:02inhibition such as MCL one.
28:03And that may be the reason that
28:06we're seeing some of those relapses.
28:08But ultimately we want to ask is this,
28:10is this something that can
28:12be applied in the clinic?
28:15And this is, this is a drug that
28:16is being tested in the clinic.
28:18It's called a BVAB BV637 made by Avi.
28:23And at this year,
28:25this past year's ESMO meeting,
28:26my colleague Julia Rotor from Dana
28:30Farber presented the clinical data
28:32of giving this agent by itself or
28:35in combination with chemotherapy
28:37or with with awesome mertinib.
28:39So here it's given monthly and the
28:42awesome mertinib is given every day.
28:44And the good thing is that the combination
28:46is actually quite well tolerated.
28:49There's some liver function
28:51abnormalities that you can see.
28:53But no, there was no major interactions,
28:55there's no major platelet decreases
28:57as we'd expect from the preclinical
29:00data and no bad toxicities that would
29:05get us worried about potentially
29:07moving this combination forward.
29:08So our our plan is to try to move
29:11that forward and use it in that same
29:13scenario and patients that we saw in the
29:17in the mouse models.
29:19And in fact in that presentation,
29:21these were all patients that have been
29:24treated previously with Asamertinib
29:25and in some of those patients that
29:27combination actually led to tumor
29:29shrinkage which was very nice to see
29:32and encouraging to helps move that
29:36forward for clinical development.
29:41So another, so I talked about that
29:43vulnerability and then the other option,
29:46other thing that we're doing is asking
29:48of this sort of intermediate state,
29:50are there novel targets that could be
29:53expressed in this state that we could
29:56go after with therapies that are in
29:59the clinic or therapies that need to
30:01be developed for clinical application.
30:04And so we've done some RNA sequencing
30:07analysis and untreated cells and cells
30:09that are in this sort of persist or
30:11state focusing on specifically looking
30:14at cell surface proteins as targets.
30:16And for many cell surface proteins
30:18there are antibody drug conjugates
30:20which are that are in the clinic.
30:22So antibodies linked to not in the, not,
30:25not the BCL XL inhibitor that I showed,
30:28but to chemotherapy and so having
30:30a more sort of targeted way of
30:33delivering chemotherapy to two cells.
30:35And these are just three of them.
30:37And we see them that they're both sort
30:40of enriched in that sort of state after
30:43treatment with an EGFR inhibitor here
30:46you can see them by by Western blotting.
30:49You can see in these EGFR mutant
30:52cancers this black band is this
30:54TROP 2 protein that's enriched after
30:56treatment with an EGFR inhibitor.
30:58This is full R1 which is a folate
31:01receptor that's also increased and
31:03it's not just limited to EGFR.
31:04Here are cells with other genetic
31:06alterations and ALK rearranged cell lines.
31:08We're treated with an ALK inhibitor.
31:09You can see the same thing,
31:11a Med amplified cell line treated with
31:13a Med inhibitor or K Ras mutant cell
31:15line treated with AK Ras inhibitor.
31:17You can see the the same things
31:21and
31:24again ALK and raw cell lines
31:26showing the showing the same thing.
31:28This is for the folate receptor and
31:30this is for trope trope too and we've
31:34also used our animal models and and
31:36and and some are cell line models,
31:38some are patient derived models to
31:41study that state that we I mentioned
31:43earlier in the presentation where
31:45we initially studied it from cells
31:48and grown in plastic but here we
31:50can study it from animals and here
31:52you can you can see the animals
31:53are treated with EGFR inhibitor,
31:55EGFR MEC inhibitor and they
31:57have these very nice responses.
31:59So the time of this maximum response
32:01we dissect out the kind of the
32:04residual area where the tumor is.
32:06We purify the tumor cells and
32:07can do all all different types of
32:09analysis on the tumor cells to ask.
32:11This has also happened in in in vivo as
32:14opposed to just in a tissue culture model.
32:17And so here's one example of different
32:21models treated with Asamertinib,
32:23Rasamertinib in the MEC inhibitor.
32:24This is the what the tumors look like
32:26when we dissect them out in the in
32:28the sort of minimal residual state.
32:30And if we look for expression of trope 2,
32:34we can see that it's a membrane
32:36bound protein.
32:36So you can see it expressed here
32:39more intensely than you see it
32:41in the in the untreated models,
32:43although you do see some expression
32:45in the untreated models.
32:46And if we quantify this,
32:48the models tend to have some baseline
32:51expression which is then enhanced with e.g.
32:54FREGFR MEC treatment and it kind of
32:56varies a little bit from model to model.
32:59This is the same experiment
33:00for this folate receptor.
33:01It seems to be much you don't
33:03find it in the untreated but you
33:06do find it in the treated one.
33:08So we like these kinds of examples
33:11because the hope would be that this
33:14is something that's specifically
33:16induced in the tumor cells and
33:18hence any therapeutic strategy
33:21should be should hopefully
33:22have a wider therapeutic index that it's
33:25targeting the tumor and not normal tissues.
33:27But wait to see that and here it's
33:31we look at it by RNA sequencing,
33:33same idea, we can look for these
33:36different cell surface proteins
33:38that are up regulated and for which
33:41there are antibody drug conjugates.
33:44And we also have a trial where
33:46we're trying to understand this.
33:47This actually happened in
33:49patients and so this is a trial,
33:51a very straightforward trial where
33:52newly diagnosed lung cancer patients
33:54were treated with Osamerton,
33:56they've been the EGFR inhibitor in the
33:58primary goal of the trial was to study
34:01how do cancers develop resistance to
34:03Asamerton when it's clinically visible.
34:06But what we built into this trial is
34:08that during the sort of maximal time that
34:10the person has had a response to therapy,
34:12we biopsy that area if we can find
34:15it and do analysis to see can we
34:19find these proteins expressed that
34:21I showed in the preclinical models.
34:23This is just an example of a patient.
34:25Here's two months of ASA Merton if not
34:27the most dramatic reduction but and
34:29here you may able to see the biopsy needle,
34:32we're biopsy in the individual and a
34:35study only has on treatment biopsy.
34:38So we don't have the pre treatment
34:40to compare it to.
34:41But at least by single cell RNA sequencing
34:43in the on treatment biopsies we can
34:45find a cluster of tumor cells that
34:47express trope here in this case trope 2.
34:49So at least we think that this is has
34:52some real relevance in patience and
34:57are trying to validate it further.
35:01So what is Trope 2?
35:03Trope 2's may be familiar for
35:06our clinical audience,
35:08but it's a intracellular calcium
35:10signal transducer that's over
35:13expressed in many epithelial cancers.
35:16There are agents that target trope 2.
35:18Here's an antibody linked to A
35:22chemotherapeutic agent in red here
35:24that's still infused intravenously
35:27and then binds the tumor cells and
35:29then this chemotherapeutic agent
35:31is internalized and cleaved in the
35:33tumor cells like a Trojan horse.
35:35And then specifically can can
35:39kill the tumor cells.
35:41And if we use this agent
35:42in lung cancer patients,
35:44you can see about 1/4 of patients
35:46have tumor shrinkage and some of them
35:48have more dramatic tumor shrinkage.
35:50This is given to a wide variety
35:52of patients with lung cancer.
35:54What we've learned over the last
35:56couple years is that it works
35:58perhaps particularly well in cancers
36:00that have the EGFR mutation.
36:03If we isolate this experiment to patients
36:05whose cancers have genetic alterations,
36:08about a third of them
36:09have real tumor shrinkage.
36:11And if you look at the specifics of them,
36:13most of these have EGFR mutant cancers
36:15although there are others in there as well.
36:17And but this year's ESMO meeting
36:18or last year's ESMO meeting,
36:20this was studied in more detail.
36:22And patients that have an EGFR mutation,
36:24they tend to have a greater response
36:27than cancers that have other
36:29genetic alterations for reasons
36:30that nobody understands yet.
36:32But it's something that we're
36:35keenly interested in investigating.
36:37So we then use that the same sort of
36:39in vivo model and ask the experiment
36:41if we now target this stroke two
36:44protein after this persistent state
36:46has been established, doesn't matter.
36:48So again treat the mice with asamertinib,
36:50some are, some continue on asamertinib
36:54and some are given this troph
36:572 antibody drug conjugate which
36:59is approved in breast cancer,
37:00not lung cancer.
37:01And in fact the clinical trial and
37:04lung cancer just failed unfortunately
37:06and again treat him and then we
37:10withdraw the drugs and there is
37:12a little bit of a difference.
37:13It's not humongous,
37:14but there's a little bit of a difference
37:16in the tumors that got treated with
37:19a Trop 2 antibody drug conjugate.
37:21On the other hand,
37:23when we take this out longer days,
37:26they all start to regrow.
37:27So we didn't really cure any of
37:30the mice here using this approach.
37:35So this Trop 2 protein expression
37:38increases following therapies that
37:40directed directed at the right
37:42genetic alteration in lung cancers.
37:45Adding this antibody drug conjugate
37:47once this tolerant state has been
37:50formed didn't really eradicate these
37:52cells because otherwise the cancers
37:54wouldn't have been able to grow back.
37:56And so where do we go from here?
38:00There are other antibody drug
38:02conjugates targeting this
38:03protein that may be more potent,
38:05which could be an issue here,
38:06one made by Dai Ichi and being developed
38:10by Dai Chi and AstraZeneca called DS1062A.
38:15Do we need to increase the
38:16duration of the treatment?
38:18Is that an issue here or can we
38:21develop some novel strategies here
38:22And and I'll I'll show you one
38:24novel strategy that we're evaluating
38:26that that and that is developing
38:29CAR T cells directed at trope 2.
38:33So chimeric antigen receptor T cell
38:37therapy type of immune therapy is being
38:41used in lots of hematologic malignancies
38:44and has done wonders there on a therapy.
38:49Just this strategy in general
38:52has struggled in solid tumors and
38:54part of the issue is that you're
38:57targeting you have to target a
38:59a specific cell surface protein.
39:02If that cell surface protein is
39:04also present in normal tissues,
39:05then you're then you're delivering this
39:08effective therapy to normal tissues
39:10and that can lead to a lot of toxicities.
39:12And so you need to try to
39:16identify two unique proteins,
39:18tumor antigens,
39:18proteins present on the surface of
39:20tumor cells that are not found on
39:22normal cells and that's remained a
39:24challenge in the solid tumor field.
39:26And this is work we've done with Eric
39:28Smith and Elliot Brea at Dana Farber.
39:32So this just shows you what
39:34these things look like.
39:36And so if we use these cells in again
39:39in a tissue culture model and we
39:42take those EGFR immune cancer cells
39:44and genetically remove trope 2.
39:47So the target of where the antibody is
39:49supposed to bind the the cells do nothing.
39:51Here in red and in green is a non
39:54specific or a a CAR T cell against the B
39:57cell antigen that isn't expressed at all.
40:00So if you knock it out or make a CAR
40:02T cell against an irrelevant protein,
40:04nothing happens.
40:05If you enter these knockout cells,
40:09replace the normal form of trope too,
40:12and now you can see less cells survive,
40:16or in the endogenous cells,
40:17less cell survives versus targeting
40:20AB cell antigen doesn't do anything.
40:23We of course wanted to make sure that
40:26the EGFR inhibitors weren't toxic
40:27to these CAR T cells and they're
40:30not except when you get to very
40:32high concentrations.
40:33So then we then we asked the experiment
40:35of first treating them with the EGFR
40:38inhibitor and tissue culture model and
40:40then to set up that drug tolerance state
40:43and then expose them to the CAR T cells.
40:46And.
40:47And similarly,
40:47if you've knocked out trope 2,
40:49nothing happens.
40:50And in the endogenous EGFR immune cells,
40:53they're very effective,
40:55Very few cells survive.
40:57And if you've replaced the
40:59normal into this knockout cell,
41:00replace the normal form of trope 2.
41:02So now it's expressed.
41:03Now they're once again effective
41:05like in the normal situation.
41:06So we do think it's doing what what we
41:10expected to be doing at least in in vitro.
41:13And we've now also again finally
41:15taken the same experiment and
41:17are starting to do it in vivo.
41:20Treat the tumors for 10 days or 21 days.
41:24Randomize them to continue EGFR inhibition.
41:28Use the continue with EGFR inhibition
41:30and the and the trope to antibody drug
41:34conjugate or a CAR T cell against
41:37the B cell antigen or against trope
41:40to just delivered once and then
41:43ask what happens to these animals.
41:47So they're delivered here.
41:48This is the schedule for the ADC
41:52delivery and then the CAR T cells
41:54are delivered also here at day 21.
41:57And you can see that the ones that
41:59are treated with the EGFR inhibitor
42:02alone all managed to regrow.
42:04The ones that are treated with the
42:07targeting an irrelevant protein
42:09also regrow and purple behind it.
42:12And the ones that are treated with the
42:14CAR T cell or in this case the ADC,
42:16the Sazotuzumabe and Goba T can't
42:19have the separation.
42:20And if we look at this long term,
42:22we certainly see that the ones
42:24that receive the trope 2 CAR T
42:25cell have a much better outcome.
42:27There are some escapers here
42:28and we're trying to understand
42:30why do they escape therapy.
42:31All of the ones treated with the ADC like
42:33in our prior experiments start to regrow.
42:35Similarly with the EGFR inhibitor by itself
42:37and and also most of the ones that are,
42:40there's one here most of the ones
42:42that are treated with irrelevant
42:44or B cell antigen CAR,
42:45T cell also start to regrow
42:47as as we'd expect.
42:51So I talked about this drug tolerant
42:55persistent state that can give rise
42:57to a broad range of actual drug
42:59resistance mechanisms and it's
43:01really one step why are one reason,
43:04not the only reason but one reason
43:07why are effective targeted therapies,
43:10precision therapies in lung cancer although
43:13effective they're not effective forever,
43:16they ultimately resistance happens
43:18in most if not all patients.
43:22And this state,
43:23what I'm trying to was trying to
43:25convince you is this state has some
43:27unique biologic properties and expressed
43:28potentially novel cell surface targets
43:30which can be leveraged therapeutically.
43:34And if we prevent the formation of this
43:37state or specifically treat the state,
43:39we may be able to extend the benefits of
43:43of our genotype directed therapies and
43:44lung cancers and maybe in other cancers.
43:47But this needs clinical validation and
43:50of course the issue that I mentioned
43:53that some of these proteins that are
43:54expressed in these drug tolerant states
43:56also expressed in normal tissues which
43:58may limit the therapeutic window and
44:01and again one reason why or 111 big
44:05reason why clinical validation is needed.
44:08So I just wanted to thank just acknowledge
44:10the many members of my laboratory who've
44:12been worked on these various projects.
44:14Here on the left hand side in the
44:17middle are my long term collaborators
44:19in the in this field,
44:20Nathaniel Gray who's a medicinal chemist,
44:22Mike Eck who is a structural biologist,
44:25biochemist and Kwak Wong who does
44:27animal models of lung cancer.
44:29We've worked,
44:30had the pleasure to work together
44:33for the last 10 years or so except
44:35during that time both Nathaniel
44:37and Kwak left Dana Farber.
44:38But we still continue to work together
44:41and still just submitted APO one together.
44:43So we'll hopefully be able to do this.
44:46The clinical,
44:47we have a lot of wonderful clinicians
44:50and clinical trialists who will run the
44:53clinical trials that I mentioned to you.
44:56That couldn't be done without our
44:58clinical research staff and patients
45:00and families who participate in clinical
45:03trials or translational research
45:05undergoing on treatment biopsies which
45:08may not benefit them directly but may
45:11ultimately help develop new therapies.
45:13We use a lot of bioinformatics in our
45:16analysis and with that couldn't be
45:19done without the bioinformaticians,
45:21the Belfer Centre that I helped run.
45:23These are many of the members are
45:24there and of course we need to have
45:27collaborators in the pharma industry
45:29who are developing many of these
45:30drugs to be able to
45:34to carry them out and hear some
45:36collaborators from AstraZeneca,
45:37Daiichi Sanchio and AbbVie.
45:40My collaborator Dave Barbie on
45:43the and Eric Smith and Elliot
45:46Abrea works with Eric and Dave
45:49on the on the car T cell studies.
45:52I just want to acknowledge them.
45:53And of course, none of the work
45:56would be possible without funding.
45:58And these are many of the
46:00funding agencies that have
46:04supported the work over the years.
46:06So I will stop there and happy to
46:08take any questions. Thank you again
46:10for the invitation to be here.
46:22Thank you so much, Posse,
46:23for really a fantastic talk.
46:26It was so clinically relevant
46:28and you're doing amazing work
46:30to really advance this field.
46:31So thank you again for all
46:32of that and for being here.
46:34So as is tradition,
46:35the first question goes back
46:36to Vito Calabrese. I don't
46:41know. All right. OK.
46:42Additionally, I asked a first question,
46:44even if I have nothing to say.
46:47But I was wondering whether in other
46:51types of cancers like Melanoma which
46:54got treated from nothing and then had
46:58the same intermediate stage developed
47:01where there were some cells of this
47:03sort and they found ways of going
47:05after them or whether there there was a
47:08total treatment from the first time. So
47:13depends a little bit on the type of therapy.
47:15But this sort of intermediate state
47:17does exist in other cancers if they're
47:19especially if they're treated with the
47:21targeted therapies that I mentioned.
47:23I think the difference in
47:24Melanoma is that it's a very,
47:26it's a cancer that we can effectively
47:29treat with immune therapies that
47:31are already exist and were developed
47:33in Melanoma and other cancers.
47:35They do work in lung cancers as well.
47:37They just don't work in the lung cancers
47:39that have these genetic alterations
47:40where we use these targeted therapies.
47:42And so that's why we need
47:44different approaches.
47:45But it isn't this example.
47:46This sort of pattern isn't
47:48unique to lung cancer,
47:49does happen in other cancers as well.
47:53Hi, I'm. I'm Steve Calabresi, Dr.
47:56Calabresi's son. And I'm a law professor.
47:59So this question may not be
48:01thoroughly relevant, but my father
48:05had a cancer of the tongue in 1975
48:09on the left side of the tongue and
48:12was given a 15% chance of surviving.
48:15He ended up living another 25 years.
48:17The way he treated the cancer of the
48:20tongue was to have surgery on his
48:23tongue and to have the glands on
48:25the left side of his neck removed,
48:28which turned out to have cancer
48:30cells in them. He had chemotherapy,
48:33He had radiation therapy with
48:35radioactive needles in his tongue,
48:37and he even used, in 1975,
48:40a primitive form of immunotherapy.
48:43And his idea was to throw everything,
48:45everything at it, basically.
48:47And so I wondered with these
48:50persistent can cancers,
48:51can you once you reduce the size of
48:53the cancer to a smaller location,
48:56is there any chance of gaining
48:58anything by surgically removing it.
49:00Obviously microscopic cancer cells
49:02might remain but maybe those would
49:04could be targeted by chemotherapy or
49:06yeah so in in the,
49:07in the EGFR example and Roy knows
49:10is very well since he led the the,
49:13the, the trials patients who have
49:15earlier stage lung cancer which we
49:18can potentially cure with surgery
49:20although it can still recur.
49:22We now use these effective like the
49:25the EGFR inhibitor as an adjuvant.
49:28So after surgery patients may get
49:30chemotherapy and then they get the EGFR
49:32inhibitor for multiple years there.
49:34We know that that not only reduces the
49:38likelihood of the cancer coming back,
49:40but it makes people live longer.
49:43Now whether whether it ultimately
49:45cures those cancers,
49:46I think we don't know yet,
49:47but at least the early signs are
49:49all going in the right direction.
49:52So yes,
49:53absolutely we're trying trying to
49:56take what we learn in studying
49:57patients with advanced lung cancer
49:59and moving the effective therapies
50:01into earlier settings where we can
50:03hopefully cure more patients with
50:04the with the disease as as long
50:06as we can find the the cancers in
50:08the earlier stage which remains
50:09a challenge still
50:13really nice talk. I'm wondering if
50:15drug therapy is acquired through
50:17somatic mutations or if there are
50:20pre-existing cells that then
50:22grow out that account for the.
50:25Yeah, both can happen and there's
50:27and and and and certainly there are
50:29examples in lung cancer and then
50:31EJFR space where you can find the,
50:34you know, you know one in a million
50:36cells you can find the resistance
50:38mechanism cancer with a resistance
50:40mechanism already there and then
50:43over time it gets selected for.
50:46But the other way around,
50:48the other other is also true
50:50that you may not find it,
50:51but it's this intermediate state for
50:54whatever reason then is denied us for many
50:57different resistance things to evolve,
50:59and part of the reason to
51:01to of course go after that.
51:03But both do exist.
51:05Both both paths to resistance are possible.
51:08Doesn't mean they can't coexist either.
51:15Hi, Pasi, it's good to see
51:17you and thanks for coming.
51:18It's beautiful work.
51:20I wondered if in the studies
51:22that you use the combination of
51:25your BCLXADC and ASA Mertonib,
51:27did you add, did you do any
51:29studies combining that with the
51:30MEC inhibitor because it looks
51:32like that's your preclinical
51:33data with support that triplet.
51:35Yeah, We we didn't, we didn't.
51:37And part of it is that it's,
51:39it's tough to take the MEC inhibitor
51:42combinations forward clinically
51:43because of the MEC inhibitor toxicity.
51:45And so we wanted to stick to strategies
51:49that we could ultimately test in the
51:51clinic in the form of a clinical trial.
51:54And as you said,
51:55we're doing a trial of ASA,
51:56Merton and Ben Celimetin,
51:58but even that and even giving it an
52:01intermediate or intermittent dose levels,
52:03not everybody can tolerate it.
52:05The MEC inhibitor toxicity adds up over time.
52:10Thanks.
52:12I'm going to ask a question
52:14as I walk over here POSI.
52:15I think you know one of the studies
52:17that I was really struck by is the
52:19the study that you did where you
52:21buy up did on treatment biopsies.
52:22I think it's something we a lot of
52:25trials have them as optional biopsies
52:26and I think sometimes we feel it's hard
52:28to to have patients go through that.
52:30I'm just curious your experience in
52:32the clinic because it's such important
52:33samples how how it was talking to
52:35patients about that and getting those
52:37samples and the importance of those
52:39most most patients that this
52:43trial and other trials as you
52:47mentioned require on study biopsies.
52:49And I think we're most of our patients
52:53are willing to assuming it's safe and
52:56the tumors in a location that can be
52:58biopsied are willing to undergo that.
53:00You know after we explain to them and you
53:04know although it may not help them directly,
53:06it'll help the development of medicines
53:08that we're trying to develop and
53:10it'll help others in the future and
53:12we do we we are have been able to
53:14be successful in that but it is it,
53:17it is optional in most cases
53:20optional typically means not done.
53:22So so yeah it it remains a challenge
53:27a really great talk
53:29as a radiation oncologist.
53:30One thing I worry about is,
53:31is there evidence of the senesa state
53:33being more or less ready resistant
53:35initial tumor and clinically it might
53:37be relevant patients got you know
53:39a handful of brain Mets and right
53:40now if they have an EGFR option
53:41do we do radiosurgery upfront,
53:43do we just do EGFR therapy and then
53:45watch wait for it to come back.
53:46When's the right time to kind
53:47of incorporate
53:47right. And there there there is,
53:49there are studies that are looking
53:50at this you know for EGFR therapies,
53:53you know patients who have sort
53:55of maximal response radiating the
53:57sort of the remaining areas and and
53:59and there are some studies that
54:00suggest that that may be beneficial.
54:02And we typically have a radiation
54:07oncologist see our patients have
54:08that they've had a maximal response
54:10to whatever targeted therapy to
54:11ask is it feasible,
54:12is it in a location that can
54:15you know that that is can be
54:17done in terms of brain lesions.
54:22I think as medical oncologists
54:24we prefer to have pharmacologic
54:26approaches to treat brain lesions,
54:28although we rely heavily on our
54:30radiation oncology colleagues
54:32for stereotactic radiation.
54:33But if we can avoid things like
54:35whole brain radiation with
54:36using pharmacologic agents,
54:38I think that would be preferable.
54:40But not all of our agents as you know
54:43across the blood brain barriers.
54:46Posse, thanks so much for
54:47being our visiting professor.
54:48As you know as well as anyone,
54:49it's now 20 years since the EGF
54:51reputations were discovered.
54:52Your lab was of course one of
54:54the key labs in that and it's so
54:56tantalizing to have these oral
54:57agents and patients live longer.
54:59But as you mentioned,
55:00no one's ever really cured.
55:02So now you've described to us adding
55:03different agents in that add toxicity.
55:05So my question is going to be
55:06about that it really does change
55:08the course of a patient's life as
55:09you start adding in some of these
55:11toxicities with you have to come in
55:13for intravenous infusions exactly.
55:14So my specific question is going to
55:16be something we're interested in here,
55:17some of the the pulmonary toxicity we
55:19see with these antibody drug targets.
55:21Is there anything that's known
55:22about structure function and will
55:24there be ways to ameliorate that?
55:25Because certainly you take
55:27someone with a long life span,
55:28but you if they end up having
55:29a pulmonary crisis that could
55:30be of course very devastating.
55:32Yeah. I don't think we as a field
55:37completely understand why some of
55:39these antibody drug conjugates
55:41give a rise to pulmonary toxicity.
55:44Or of course it is the the, the one of
55:48the more feared toxicities because A,
55:52that can be symptomatic and B typically
55:54means you have to stop using that treatment,
55:56even though if it's if it's been
55:58effective because you don't want to,
56:00you know, make the toxicity worse.
56:01But our mechanistic understanding of
56:04what gives rise to that I think is at
56:07its infancy still and I think something
56:10that we should continue to work on.
56:12And they're not great models like mice don't
56:16get interstitial lung disease from that.
56:18So you have to have a good
56:19model to be able to study in.
56:22I think we have time for one and
56:24maybe two questions. So just
56:25my question come from pathology NGS,
56:28so this persistent cells.
56:29So when we get that tumor treated
56:31and recurrent, we see additional
56:33mutation in GFR amplification,
56:35some tumor exchange to become
56:36neuron decrin and squamous.
56:38These persistent tumor cells where
56:39they are located in in these pathways
56:44typically as I showed you pre
56:46clinically typically if we take
56:48one of these persistent
56:49cells and do NGS on them,
56:50they don't have any other genetic
56:52alterations compared to the parental
56:54because they're basically just
56:56rewired to be able to survive.
56:58And if you in that preclinical
57:00experiment if you take off the drug
57:02they regrow and they're the signaling
57:04pathways look like look the same
57:06as they do in the parental cells.
57:08So it's it's it's sort of an adapt,
57:11it would fall under sort of an
57:13adaptive resistance that allows
57:15survival but not necessarily driven
57:17by a specific genomic mechanism. OK,
57:21David, I think this will
57:22be the last question from pathology.
57:26So the protein expression of
57:28both trope 2 and EGFR spans
57:30about a two log dynamic range.
57:32Have you ever looked at the levels
57:34of protein expression to correlate
57:35with your ADADC effects that you see?
57:37So clinically that's been looked
57:40at and disappointingly has no
57:43correlation with the efficacy of
57:45Trope 2AD CS or her three AD CS.
57:47Now maybe it's because we don't
57:50have the right assets to look at.
57:54Maybe it's because other things you
57:57you need the expression of the target,
57:59but you need other things.
58:00The antibody has to bind the target.
58:03It has to be internalized.
58:04It has to be transported to the right
58:06cell compartment where then the the,
58:08the the conjugate is cleaved and and
58:10and then can kill the tumor cells.
58:13So maybe maybe there are other things
58:15that are important in that in that
58:17overall efficacy as well not just the
58:19expression of the of the of the target.
58:24Great. Well possibly.
58:26Again, thank you so much for really a
58:28fantastic talk and for coming to visit.
58:30I will just make one announcement
58:32which is after this in the next
58:33couple minutes we're going to gather
58:35outside and and the fellows and
58:37other trainees are going to have a
58:38chance to ask you more questions and
58:40really look forward to that as well.
58:42Thank you again.
58:44Thank you.