Pharma Strategy Blog

Commentary on Pharma & Biotech Oncology / Hematology New Product Development

Posts tagged ‘Calistoga’

For as long as anyone can remember, humanity has wondered, “Why do we do things even when we know we should not?”

James Shelley, Caesura Letters

Akrasia is a rather common affliction in Pharma and Biotech.  After all, why do so many companies fall into the deathly trap of running generic catch-all studies in heterogeneous cancers without an oncogenic target or validated biomarker? Or even specific, well defined subsets to improve the homogeneity ratio?  Or perhaps they knowingly underpower a randomized trial for overall survival?

The list goes on…

Later, senior executives predictably scratch their heads bemusedly when the results come in — and they’re not what they hoped for, or were expecting. No one stopped to ask the obvious question – how can you hit a target you don’t have?

A head-desk kind of moment to be sure.

Hope is not a viable strategy in this business. It’s simply too expensive to shackle the odds against you in the face of intelligent analysis or solid evidence.

That said, rather than rant about this (again), I wanted to take a look and explore R&D and oncology drug development in a more positive light. There are plenty of succeses that have either made it to market or are very close in phae III development in oncology and hematology. It’s always a pleasure to find enlightened and intelligent souls in this realm, people with clarity of vision and a driving passion to get things done right.

I was really thrilled to meet one such person at the American Society of Hematology (ASH) meeting in New Orleans recently in person.

gallagher_bioDr Carol Gallagher, the former CEO of Calistoga and now VC Partner at Frazier Healthcare was truly a delight to chat with. Many of you will recall the stunning early data for what was then CAL-101 (now idelalisib), a PI3K-delta inhibitor in hematologic malignancies such as B cell lymphomas and leukemias (indolent NHL and CLL). They were the first to demonstrate the proof-of-concept for the target and published early clinical results that got people’s attention.

Rather than describe an interview – it was more like a fireside chat between two people with a similar vision – I wanted to share some of the ideas we discussed in New Orleans. The parallels between our experiences with idelalisib and imatinib were quite striking to me… From the central focus on the science and the patients, to the carefully thought out clinical program development etc… only to end up with a sudden realisation that you’ve both gone through similar experiences, with an identical philsophy; “what you too?!” is both pleasant and unnerving at the same time!

Pharma Strategy Blog: One of the things that I was interested to learn is what is your general philosophy with R&D? Strategically, what are you trying to accomplish?

Dr. Gallagher: I think we are at a moment in time that I feel fortunate to be part of where the last 20 to 30 years, we’ve had a much better molecular understanding of what drives the cancer cell. What I’m particularly fascinated with is I think we’re getting even more of an understanding of how that cancer cell is interacting with its environment and the immune system and, of course, as evidenced by PD-1 and the PD-L1, it’s fascinating to now think about that interaction. This has given us a lot of opportunities to think about specific molecular targets that could be drugable, and that could be either a small molecule or antibody, depending on, of course, where the target is, and how we’re thinking about drugging it. That (concept) has changed everything, because we can be more specific in our targeting versus giving people poison.

I think that it’s certainly an efficacy story, but it’s actually a quality of life story. I don’t mean by that registrationable endpoint of quality of life, but I do mean it in the sense of when you’re diagnosed with cancer, don’t you want to try to find a way to manage that disease, but in a way where you could still see your grandchildren or make your daughter’s high school graduation? Certainly, chemotherapy agents have been quite effective. In breast cancer, where it’s a very chemo-responsive disease, it’s hard to imagine that it’s completely going away, but can we find opportunities to give patients therapies that might be more consistent with a good life experience as well as treating their disease?

I was fortunate, for a brief amount of time in my career at Agouron to actually work in the HIV space in those early days of HIV treatment and the protease inhibitors. That was what enabled new products to come very quickly and take over space was that the opportunity to improve the adverse event profile was significant, even though, of course, just even getting the disease treated initially was a major step, but then we were able to actually rapidly, through the industry, improve upon the overall experience for those patients. I think we’re still trying to do that because when you’re living with the disease in a more chronic way, you want to be able to have better therapies.

I have to say the important thing is to focus in on each cancer type because they are all different. I think that the Gleevec example was something we majorly needed for those patients. Now, actually, interestingly, we’re having to manage that, wow, they’re actually living long enough of a time to now have mutations emerge where before, we were just focused on giving them some additional time, and so it’s really great that we’re transitioning.

I saw that too. I worked on Rituxan for a few years at Idec managing that relationship with Genentech, and this was in the early 2000s. What I started to appreciate – that I think has played out in CLL and indolent NHL – is these patients actually do live a fairly long time from the time of diagnosis. It really does matter how much the adverse event profile plays into your life, which is why lots of people would end up choosing single agent Rituxan even though we knew that Rituxan plus chemo would give you more efficacy, but they were choosing no chemo for the quality of life types of aspects of it; again, not meant as a registration endpoint but more of just how you feel every day.

I think that’s where today in R&D, we have to think about the targets but also the patient and their specific disease, and how do we give them true clinical benefit, which is not just efficacy, it’s how do we make their life experience with this disease hopefully better or not so interrupted by having cancer?

Pharma Strategy Blog: I learned that a lot from the Gleevec patients who had advanced. Some of them had six months, if that; maybe some of them had a year. I would go to visit the investigators, and sit in the clinic, and talk to the patients first, and see the PIs at the end. One didn’t want to see them in the middle and get preferential treatment over the patients, but it was a wonderful experience to talk to them, to learn about what is it really like to live with CML or whatever.

Some of them would open up—one lady, she told me she had already booked her funeral! I didn’t know what to say to that and she said, “I want to live long enough to make my daughter’s wedding.” It was six months hence. I found out afterwards from the doctor, “If she gets in the trial, she might live six months. It will be touch and go.” She’s still alive today, and that was 2000, probably 1999/2000, and you start to think about that. Wow, she’s living ten, 11, 12 years for a disease that previously, you had maybe, at the outset, a year.

The other side of this, you don’t necessarily think about at the time, is exactly what you’re saying, is if you turn an acute disease into a chronic one, they have to live with those side effects. We all know the TKIs and antibodies, if you take them for a long period of time, you’re going to have side effects. Some of that aspect of it, and you can see it in CLL with the FCR vs FC or BR in the German trials, where they can argue as long as they like that one is better than the other. But when you look at the side effects and how long patients are getting the side effects, often months afterwards, you can see why patients would choose to take single agent rituximab and feel okay. They might feel a little tired, but they’re not going to get horrible side effects, and I think that’s one of the things that we’re seeing more of in CLL. You can almost imagine with the new CLL11 study that many of these patients with co-morbidities will choose obinutuzunab alone over the combination with chlorambucil, irrespective of the label.

This morning, I went to the ASH press briefing and they had – I still think of it as CAL-101 – they had the idelalisib data, and it looked pretty impressive, but the side effect profile was also, I thought, quite impressive. Patients weren’t having a lot of the dreaded GI effects like nausea, vomiting, diarrhea etc, you could imagine that they’re not distressed and chained to the bathroom. It’s a huge difference.

Dr. Gallagher: Particularly, with that being a patient population where the average age at diagnosis is, I think, 75, and so we’re not talking about a 40-year-old person. We’re talking about a person who likely has other co-morbidities that are challenging for their daily life and to be able to do that.

It was interesting, when we first started thinking about that combination, having worked on Rituxan, I was interested to think about would there be—could idelalisib have enough activity in CLL to be close to a combination that would be R-chemo? That was really our hope, in the sense that then people would have an option—at least earlier in the progression of their disease—that might not be so toxic or causing just daily living skills to not be as easy to do. Is that an opportunity that we actually could see? Of course, the nature of the leukocytosis that is caused where we’re pushing those cells into the blood, we saw early on in the combination work, exploratory work that we did that when you put that with Rituxan, it just cleared everything rapidly. Of course, Rituxan is known that it doesn’t work that well in the lymph nodes in CLL. It is a more peripheral active drug, so it just seemed like an interesting combination to put together.

I have to say my own personal hope was this idea that maybe we could give people a pretty still efficacious option that would then say, “Well, maybe we could wait to do the more toxic things like FCR or even BR.” Bendamustine has its own set of challenges, given that these patients do unfortunately relapse over and over, that could we give them an option? I have to say I was thrilled that the outcome of that trial does actually have a survival benefit even. That makes me believe that we really are going to change the opportunity for those patients to have effective therapy that also allows them to hopefully have a little bit more normal life, not that there aren’t adverse events with these drugs, there certainly are, but I think in comparison, they’re manageable.

Pharma Strategy Blog: I think that one thing that comes down to this meeting, talking to thought leaders and also community oncologists in the poster session, sometimes, we forget that the academic physicians see a lot of younger, fitter, healthier patients because they’ll probably be a little bit more aggressive and educated. They want to live longer, and they’re looking for trials; whereas, in the community setting, they are the 75, 80-year-old patients that you’re talking about.

I’ve heard it so many times from these docs that, “I need something better for my patients. I can’t give them FCR or whatever, they just can’t tolerate it.” Some of them can’t even tolerate bendamustine. They care about their 75 to 80 year old patients, “It’s a big deal, Sally.” We talk about indolent disease, but for them, it’s a different goal of therapy. I do think one of the things that you really start to realize at this meeting is how a whole series of different combinations could evolve, not just idelalisib/Rituxan, but other things in combination.

Dr. Gallagher: Ibrutinib, I think we have a number of very exciting drugs, and I couldn’t be happier that we’ve really started to make some progress, and it is molecularly oriented. It’s really saying these are interesting targets around the B-cell receptor; the AbbVie compound is also very interesting. I feel so excited to be part of what I see is a new era of the dreams that we had over the last ten years are coming to fruition.

Again, it’s not perfect, and we have to keep continuing to strive to do better, but I do hope that these different agents will now offer physicians a whole new tool kit that will let chemo or FC go later into the process, if at all. As you say, 75 to 80, or 75 to 84, there may be other issues that then cause those patients to expire, but in the meantime, they get to their granddaughter’s wedding or things that are real to people.

I have to say, as I have lost my father and have an aging mother, you start to appreciate, I think—and I’m sure physicians, of course, see that with their patients every day—but to appreciate that there are balances of it’s not always just about life extension at any cost because if you’re sick in the hospital with neutropenia (laughter), that’s not actually a very good experience while your family is at home celebrating the holidays.

Pharma Strategy Blog: One of the things a Community oncologist was saying to me yesterday during a session lull was rather interesting. He turned to me and said, “We get obsessed with complete responses and remission!” Then he went on, “I’m thinking about not just the elderly patient, but younger patients. If they get these PRs, and they’re sustained, and they’re durable, and the overall responses are good, and the progression-free survival is good, does it really matter if we don’t achieve a CR?” Now we don’t know the answer yet, but I thought that was a very good question and how the durability plays out will be interesting.

Dr. Gallagher: It’s funny because Langdon Miller, who came and joined us at Calistoga, and was at CTEP earlier in his career, and then at Pharmacia Upjohn, and developed a number of cancer drugs, that was something he talked a lot about when he first came to work with us; that he really thought durable PRs and particularly in these CLL and NHL where to talk about true cure as in most cancers. To talk about true cure, where it’s going away and it’s gone forever, is a difficult thing to achieve. If you’re getting a very durable response where people can live, basically, a fairly normal life for quite a long time, isn’t that like a CR? CRs aren’t always—unfortunately, these patients do relapse, and so it’s not as if we’re talking about a true cure when even we describe CRs in these types of leukemias and lymphomas.

Pharma Strategy Blog: Even if these patients have two to three years on either a single agent or a doublet, and they have a better of quality of life than if they’d had the side effects of FCR, they can still go on to another one with so many choices that we have now.

Dr. Gallagher: Yep, exactly, exactly.

Pharma Strategy Blog: It was interesting that another oncologist in the audience turned to the doc and I and joined in; he chimed in, “Well, you know, I give FCR first line. I give BR second line, and the third line, hmm I put them on a trial for something, or they have pentostatin or whatever they haven’t had.”  He felt strongly at the end of it all though, they were really wiped out, and the patients were like, “I don’t think I can take anymore, I’ve had enough. I’d like something just to keep me happy, like a happy pill.”  He observed, rather astutely, “We need to think about this differently.”

For the Community oncologists, this is a really critical juncture now. With all these new drugs coming along, in the next probably 12 months, where they have several of new ones available and others coming along in trials, I think it will change the way we monitor these patients and how we look at the disease.

You look at the hematology extremes and you have myeloma at one end, where you have the almost nihilistic Total Therapy, and stem cell transplants and the like, yet 20% of them died from the procedure!  Okay, you might have X percent got a cure, but what’s the quality of life after that? Thankfully, in NHL and CLL at the other extreme, we’re moving into an era where there’ll be so many options to hopefully avoid drastic side effects, and it will be really interesting to see where it goes.

Dr. Gallagher: Yeah, I totally agree. I have to say, again, back to my experience of working on Rituxan, is because right before that, as I was talking about it, I was working at Agouron, which became Parke-Davis, Pfizer, and we were working a lot more on the targeted EGFR and then on antiangiogenesis agents. I’d been working more in disease settings like non-small cell lung cancer, where you’re just trying to give them a couple of more months of life.

When I moved over into these indolent diseases and started to really think about, wow, this patient has a number of years, let’s think about how their quality of life matters, it was interesting to me that the physicians themselves, again, back to the single agent Rituxan use, they were, or their patients, someone was recognizing this and making this choice, which from my very academic hat of, well, but we know FCR has a better efficacy percentage, at that time, that data hadn’t been developed. We were still working on it but R-CHOP versus R; we know that that is going to give you a higher response rate of the overall patient population. Why would you ever choose R alone and yet, people were choosing that.

It was such an education where, as you were talking about, you talk to patients, listen to the physicians that are in the Community on the ground outside of Academia, because that balance is very important. I do think that’s one of the things in the United States that’s so interesting is the way that we deliver cancer care is predominantly through the Community and the Academics are certainly very important for advancing research initiatives, but we’re very close to the patient in the United States in the way that we deliver that care. I think we have to keep that balance of listening to what they’re telling us and understanding where there may be opportunities to fill an unmet medical need that might not be quite as Academic as a response rate.

Pharma Strategy Blog: It’s a great time to be in CLL and indolent NHL. I think you’ve been very much a part of that, so I’m really delighted to meet you and hear about the context of what you were trying to do in those early days. It’s certainly coming to fruition now, and that’s really exciting.

Dr. Gallagher: I couldn’t be happier, and it was an amazing team that worked on it. I think the Gilead team has done a great job and will continue with that. There’s some of our Calistoga folks that are part of that Gilead team still, but my hat is off to all the people, all the investigators, the patients. It’s such a great community, and we have to all find a way to work together to advance this, so I really appreciate the time.

Recently at a couple of scientific cancer meetings, American Urology Association (AUA) and American Society of Clinical Oncology (ASCO), Frank McCormick described a fascinating talk about how a wac-a-mole approach to figuring out how the phosphatidylinositol 3′-kinase (PI3-kinase or PI3K) pathway could be targeted effectively with therapeutics. The reason for research in this area is PI3K has been shown to play a major role in proliferation and survival in a wide variety of human cancers, thus making is a potential target for therapeutic intervention.

I’ve been following this target for a couple of years now and data is now starting to emerge that’s worth discussing on a broader scale, given the implications.  Here’s a quick snapshot of the PI3K pathway and related pathways:

image from www.nature.com
Source: Workman et al., Nature

As many of us well know, however, simply targeting one element of an aberrant pathway can lead to cross-talk and feedback loops as the cancer tries to maintain the signals important for it’s survival, so a more cunning approach is needed whereby the escape routes are closed off one by one by targeting different kinases as well as PI3K.

McCormick’s talk was a fascinating lecture that basically went through multiple pathways explaining, ‘well we tried X and this happened, so we tried blocking Y as well and this happened…’  kind of approach in a very logical and systematic fashion.  Eventually, all options will be explored and a new paradigm might emerge.

It was therefore with great interest that I read a series of new papers in AACR’s journal, Clinical Cancer Research (see references below) over the weekend on both the pathway itself, and also new data with targeted PI3K agents in both breast and renal cancers.

The Data so far:

Miron et al., looked at PI3K mutations in in situ and invasive breast carcinomas and reported:

“This is the first study to show that PIK3CA mutation is a relatively early event in breast tumorigenesis preceding invasion because the frequency of PIK3CA mutations was the same in pure DCIS as in DCIS adjacent to IDC and in IDC.”

Given the frequency of mutations was the same for the 3 groups they studied (pure ductal carcinoma in situ (DCIS), DCIS adjacent to invasive carcinoma, and invasive ductal breast carcinomas), the data suggest that the PI3K mutation may play a greater role in breast tumor initiation than in invasive progression.

If this is the case, targeting PI3K early, for example in neoadjuvant therapy, may have a positive beneficial effect.

In the O’Brien paper, the researchers looked for predictive biomarkers of sensitivity to Roche/Genentech’s PI3Ki, GDC-0941 in preclinical models of breast cancer:

“We found that models harboring mutations in PIK3CA, amplification of human epidermal growth factor receptor 2, or dual alterations in two pathway components were exquisitely sensitive to the antitumor effects of GDC-0941.  We found that several models that do not harbor these alterations also showed sensitivity, suggesting a need for additional diagnostic markers.”

Identifying suitable biomarkers in preclinical studies, such as the HER2 amplification and the PIK3CA mutation (but not PTEN deficiency) previously identified in other studies and now validated in O’Brien et al’s GDC-0941 study, will hopefully help in better design of future clinical studies.  They also noted that decreased ERBB3 expression in PIK3CA mutant cell lines, and ERBB3 expression was increased in response to treatment with a PI3K inhibitor, suggesting that ERBB3 expression levels might be used as a biomarker for high activation of PI3K signaling and increased sensitivity to PI3K inhibitors.  This kind of rigourous approach would potentially enable selecting which people are most likely to respond up front to the agent, rather than exposing those who are unlikely to get a response to additional toxicities and side effects.

In a well written editorial, Turke and Engelman, also emphasised that:

“A novel expression profile was developed to identify other breast cancers sensitive to PI3K inhibitors. These expression studies highlighted feedback networks connecting TORC1, PI3K, and mitogen-activated protein kinase (MAPK) pathways, and underscored the potential for combination therapies.”

They also went on to observe:

“It will be interesting to determine if PI3K inhibitors induce substantial apoptosis in vitro and tumor regressions in vivo in these cancer models (without HER2 amplification or PIK3CA mutation).  Of course, it will be crucial to assess biomarkers identified in laboratory studies in clinical samples from patients who respond to PI3K inhibitors.  Neo-adjuvant trials in breast cancer patients can be leveraged to address these translational goals, because they correlate clinical efficacy and pathologic signs of response (e.g., changes in Ki67 levels and induction of caspase cleavage) with the presence of potential biomarkers.”

In another study, Cho et al., looked at the effects of a dual PI3-Kinase/mTOR Inhibitor
NVP-BEZ235 compared with rapamycin in renal cancer (RCC) with BEZ235 (Novartis). The proof of concept for mTOR has already been shown clinically with the approval of two drugs in this indication, temsirolimus (Pfizer) and everolimus (Novartis):

“These agents induce only modest tumor regression and extend progression-free survival only a few months in most patients.”

The big question here is whether targeting PI3K as well as mTOR would have any extra beneficial effects?  The results demonstrated that dual inhibition of PI3K/mTOR with BEZ235 induced growth arrest in RCC cell lines both in vitro and in vivo more effectively than inhibition of TORC1 alone. If reproduced in the clinic, this may offer a new and more effective approach to treatment of the disease.

The Future:

The PI3-kinase field is particularly interesting, with several companies snapping up PI3K inhibitors including sanofi-aventis (from Exelixis) and more recently, Infinity (from Intellikine).  Other oncology companies already have some in their pipeline, such as Novartis (BEZ235) and Roche/Genentech (from Piramed).  Meanwhile, smaller biotechs such as Semafore and Calistoga also have some promising early phase compounds in development.  Some of these compounds target PI3-kinase alone, while others target PI3K and mTOR.

This is not going to be a straightforward approach to targeting cancer and identifying biomarkers along the way will be key, as well working out the best combinations that might make a more effective therapeutic approach than single agent activity. Figuring out when best to test these agents (early or late) will also be critical. The I-SPY breast cancer trials have already led the way in creating protocols for testing novel agents in the neoadjuvant setting in breast cancer, and it may well be that PI3K inhibitors would be a good class to test in this setting based on the new evidence from Miron et al’s study.

What is particularly interesting to me is that PI3K signalling may also have a role to play in asthma and COPD (the area I did my doctoral research in) rather than just cancer.  Now that would be really fascinating as the biochemical and molecular biology overlap have long been suspected, but very little research has really evolved this way. Part of that is due to drug manufacturer silos and the inability to effectively spearhead cross-therapeutic research.

It will be fascinating to watch how the PI3K data shakes out in practice over the next few years.

What do you think?

ResearchBlogging.org O’Brien, C., Wallin, J., Sampath, D., GuhaThakurta, D., Savage, H., Punnoose, E., Guan, J., Berry, L., Prior, W., Amler, L., Belvin, M., Friedman, L., & Lackner, M. (2010). Predictive Biomarkers of Sensitivity to the Phosphatidylinositol 3′ Kinase Inhibitor GDC-0941 in Breast Cancer Preclinical Models Clinical Cancer Research, 16 (14), 3670-3683 DOI: 10.1158/1078-0432.CCR-09-2828

Turke, A., & Engelman, J. (2010). PIKing the Right Patient Clinical Cancer Research, 16 (14), 3523-3525 DOI: 10.1158/1078-0432.CCR-10-1201

Miron, A., Varadi, M., Carrasco, D., Li, H., Luongo, L., Kim, H., Park, S., Cho, E., Lewis, G., Kehoe, S., Iglehart, J., Dillon, D., Allred, D., Macconaill, L., Gelman, R., & Polyak, K. (2010). PIK3CA Mutations in In situ and Invasive Breast Carcinomas Cancer Research, 70 (14), 5674-5678 DOI: 10.1158/0008-5472.CAN-08-2660

Cho, D., Cohen, M., Panka, D., Collins, M., Ghebremichael, M., Atkins, M., Signoretti, S., & Mier, J. (2010). The Efficacy of the Novel Dual PI3-Kinase/mTOR Inhibitor NVP-BEZ235 Compared with Rapamycin in Renal Cell Carcinoma Clinical Cancer Research, 16 (14), 3628-3638 DOI: 10.1158/1078-0432.CCR-09-3022

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One of the interesting things about scientific conferences such as AACR and ASCO is that everyone looks at the same data differently as if it were through a kaleidoscope.

Brand marketers focus on their competition by tumour type or disease, scientists look at specific mechanisms or pathways, investors look at particular companies and so on. 

Someone asked me the other day how I analyse the data.  I hadn't really thought about it much until then, but on reflection what I'm interested in is trends and how research evolves from a big picture science view so that means I look at pathways like a true biochemist.  This also teaches us where the gaps are and what opportunities may arise in the future.  It's not exactly rocket science, but it is a useful approach sometimes.

Phosphoinositide 3-kinasesImage via Wikipedia

One of the clear trends emerging at AACR the other week is that dual inhibition of both the PI3K-mTOR and RAS-ERK pathways may be necessary in some cancers such as melanoma to reduce cross-talk, feedback and feedforward loops, drug resistance and loss of PTEN gain of function, just as one might also target IGF-1R and EGFR to reduce cross-talk and add in another inhibitor, eg MEK or AKT.

Given the increasingly critical role of MEK and AKT in various combinations in the future to reduce the potential for drug resistance occurring, this bodes well for a host of companies.  I wasn't, therefore, surprised to see Novartis snap up Array's MEK inhibitor (ARRY-162) given they already have an mTOR on the market (everolimus, Afinitor), two PI3-kinases in development and others including a RAS inhibitor.  Having a MEK inhibitor as well may therefore give them a lot of flexibility with different combinations in multiple cancer types if this approach pans out. 

Merck are also following a similar approach with their mTOR inhibitor, ridaforolimus, which they have finally grabbed commercial control of from their partner, Ariad.  Let's not forget they also have an AKT inhibitor, dalotuzumab and a MEKi through their partnership with AstraZeneca to play with too.

This is all good news for several biotech companies though, if some big Pharma companies start catching onto the trend and realise they need may a PI3K-mTOR inhibitor and a MEK or AKT inhibitor to stock up in their pipeline before the field gets too crowded.

Which companies might have new and interesting data in this area?

Well, Keryx and Aeterna Zentaris, Semafore, Calistoga, Intellikine and a few others all have PI3K inhibitors in development, while Exelixis have a deal in place with sanofi-aventis for XL147 and XL765 and Roche/Genentech have a pan-PI3K inhibitor, GDC-0941.  Novartis have two (BEZ235 and BKM120). Some of these compounds are single PI3K inhibitors and some are dual inhibitors of PI3K-mTOR.

Looking at the ASCO abstract titles, Exelixis appear to have the most abstracts in this area this year, so it will be interesting to see what sort of data they have across a range of different tumour models and early phase I results in solid and hematologic malignancies, with a variety of different combinations. 

One session I'm really looking forward to at this year's ASCO is a Clinical Science Symposium entitled, "Paths for Clinical Development of PI3K Inhibition" with some of the heavyweights in the field such as Neil Rosen (MSKCC), Skip Burris (Sarah Cannon), Jose Baselga (Spain) and Carlos Arteaga (Vanderbilt).  Arteaga is presenting a talk in that session entitled, "Next steps in clinical development of PI3K inhibitors?"

More later on this blog after the posters and the data become available at the meeting.

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Life is about stories, events and even coming back full circle sometimes. I experienced that moment of déjà vu this morning on opening a link to an article that a colleague kindly sent from Avrum Spira’s lab that was published in Science Translational Medicine, simply titled:

Airway PI3K Pathway Activation Is an Early and Reversible Event in Lung Cancer Development

Many moons ago I completed my doctoral thesis on the early detection of lung disease at King’s College London. Much of it was about the impact of smoking on the airways. Halfway through the 3 year MRC grant, while listening to some evening lectures at the Brompton Hospital by Prof Peter Barnes and Steven Holgate, I realised that the real answer lay in understanding the biochemical and molecular biology pathways… only we were working on the physiology of breathing patterns.  An a-ha moment to be sure.

Still, I was able to pick up differences in breathing patterns between healthy non-smokers and those who were medium to heavy smokers.

The unaswered question, though, was why?

Prof Barnes loved to put up charts of pathways with a black background and different targets meticulously coded with coloured highlighter pens… PDE, leukotrienes, cholinergic mast cell activation and many others sprang to life as he walked students through the various possible mechanisms where pharmaceutic intervention might have a role to play.

Fourteen years on, I don’t think a cure for asthma has been found and many of those pathways have not yielded much in chronic obstructive pulmonary disorder (COPD) either, except perhaps anti-cholinergics such as tiotropium bromide (Spiriva) as maintenance therapy in controlling bronchospasm. My suspicion at the time was that the mechanisms underlying inflammation and aggravation of the airways by chemicals was key to unlocking why some people get lung cancer, others COPD and still others were unaffected.

Fast forward to the article.

Last week, Gustafson et al., published a paper in Science Translational Medicine suggesting that phosphatidlyinositol 3-kinase (PI3K) pathway activation is an early event in the development of lung cancer.

In particular, they found elevated PI3K in the airways of smokers with lung cancer compared to smokers without lung cancer:

image from stm.sciencemag.org
Source: Science Translational Medicine

The researchers validated their hypothesis that activation of PI3K is an early event in the development of lung cancer by comparing the cytology of airway epithelium from healthy smokers to those with mild to moderate airway dysplasia that reflects an early noncancerous abnormality, often considered a precancerous state.  The theory being that if smokers with dysplasia have higher PI3K pathway activation then this would suggest P13K pathway activation precedes the development of lung cancer.

The results showed increased expression of genes induced by PI3K pathway in high risk smokers and those with lung cancer. This may well explain the dysplasia and inflammation seen, which you can see in the chart below:

image from stm.sciencemag.org
Source: Science Translational Medicine

One key question this research raises, but does not answer, is whether P13K pathway inhibitors have a role to play in the treatment of lung cancer?

Thinking about my doctoral research on early detection of lung disease, this statement made me sit up and pay attention:

“These results suggest that deregulation of the PI3K pathway in the bronchial airway epithelium of smokers is an early, measurable, and reversible event in the development of lung cancer and that genomic profiling of these relatively accessible airway cells may enable personalized approaches to chemoprevention and therapy.”

Whoa!  Early detection of lung cancer?

Forgive my excitement and enthusiasm, but it’s kind of cool to see read that scientists can actually find something biochemically active that may represent a new target for intervention fifteen years after you realise that early detection might be possible, if only you knew what the target might be.  That’s the stuff of <goosebumps.

PI3-kinase is a fascinating target that quite a few biotech and pharma companies are looking at as a potential mechanism for the treatment of cancer. I’ve written and blogged extensively on this (see herehere, herehere and here) for some examples.

Interestingly, many of the PI3-kinase compounds in early clinical development are investigating the agents in leukemias, lymphomas, breast, ovarian and gastric cancer or basket solid tumour trials. Some of the interesting small biotech companies in this field include Calistoga, Semafore and Exelixis and big pharma is represented by Merck, Novartis, sanofi-aventis and Roche.  Only two agents seem to be specifically looking at non-small cell lung cancer (NSCLC) though – no prizes for guessing which ones:

  1. Everolimus (Novartis), a combined mTOR-PI3 kinase inhibitor, in phase II development.
  2. GDC-0941 (Roche/Genentech), which is looking at whether the new agent adds anything to the current standard of care in NSCLC ie carboplatin + paclitaxel + bevacizumab and is currently recruiting patients.

Novartis (a client) have completed their trial according to the clinical trials database, so it will be interesting to see if there are any data at ASCO in June that will help us learn more about the disease.

If the data from the Novartis or Roche trials are positive, the companies may be very interested to read Gustafson et al.’s suggestion:

“Our work further suggests that additional lung cancer chemoprevention trials either targeting the PI3K pathway or measuring airway PI3K activation as an intermediate endpoint are warranted.”

Chemoprevention is a big word in cancer research.

In two weeks time, I’ll be at the AACR annual meeting in DC (do let me know if you are going and would like to meet up for a coffee and chat) and hopefully there will be more about this fascinating pathway then.  Watch this space!

ResearchBlogging.org
Gustafson, A., Soldi, R., Anderlind, C., Scholand, M., Qian, J., Zhang, X., Cooper, K., Walker, D., McWilliams, A., Liu, G., Szabo, E., Brody, J., Massion, P., Lenburg, M., Lam, S., Bild, A., & Spira, A. (2010). Airway PI3K Pathway Activation Is an Early and Reversible Event in Lung Cancer Development Science Translational Medicine, 2 (26), 26-26 DOI: 10.1126/scitranslmed.3000251

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