GRACE :: Lung Cancer

acquired resistance

Denise Brock

Lung Cancer Video Library – Spanish Language: Video #18 Acquired Resistance to Targeted Therapies: Biology and Different Clinical Patterns

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GRACE Cancer Video Library - Lung

 

For our 18th video in the GRACE Spanish Lung Cancer Library, Dr. Brian Hunis, Medical Director, Head and Neck Cancer Program, Memorial Cancer Institute, Miami, Florida, joined GRACE to discuss the basics of Lung Cancer for Spanish-speaking patients and caregivers.  In this video Dr. Hunis addresses acquired resistance to targeted therapies: biology and different clinical patterns.


 

 

 

 


 

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TRANSCRIPTS – Spanish and English
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Resistencia adquirida a las terapias dirigidas: Biología y diferentes patrones clínicos.

Lamentablemente inclusive en pacientes que tienen la translocación de ALK, eventualmente los pacientes van a desarrollar una resistencia adquirida, por lo cual la medicación con crizotinib no va a funcionar mas.

Por lo general, estos son pacientes que van a tener un prelapso o una recaída en sistema nervioso central o pulmón. Esos son pacientes a los cuales que uno va a considerar terapia de segunda línea o cambiar a quimioterapia.


Acquired resistance to targeted therapies: biology and different clinical patterns.

Unfortunately, even patients with ALK translocation will eventually develop an acquired resistance, resulting in crisotinib not working anymore.

In general, these patients will have a relapse or re-fall in the central nervous system or lung. In these patients, we will consider a second line therapy or change to chemotherapy.


Denise Brock

Targeted Therapies in Lung Cancer Patient Forum 2016 – Evolving Landscape with Dr. Dara Eisner

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Presented by the

Global Resource for Advancing Cancer Education
in collaboration with
the University of Colorado
Cancer Center
 
On August 20, 2016, in collaboration with the University of Colorado Cancer Center, GRACE presented the Targeted Therapies in Lung Cancer Patient Forum in Aurora Colorado.  In this eighth video from the webcast series, GRACE presents the lunchtime keynote discussion: The Evolving Landscape of Molecular Testing in Lung Cancer: Who, How and When? featuring Dr. Dara Eisner.

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(click for speaker slides)
The Evolving Landscape of Molecular Testing in Lung Cancer: Who, How and When?
 


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Denise Brock

Targeted Therapies in Lung Cancer Patient Forum 2016 – Breakout Session EGFR

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Presented by the

Global Resource for Advancing Cancer Education
in collaboration with
the University of Colorado
Cancer Center
 
On August 20, 2016, in collaboration with the University of Colorado Cancer Center, GRACE presented the Targeted Therapies in Lung Cancer Patient Forum in Aurora Colorado. We are happy to share the videos from this live and webcast forum. Our sixth video is from the forum breakout session for EGFR patients and caregivers, featuring co-chairs Dr. Greg Riely and Dr. Jack West, and patient moderator Bob Fuerst.

Download the Agenda and Speaker Bios

(click for speaker slides)
EGFR – Acquired Resistance Treatment Options
EGFR – The Road to Resistance
 


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Dr West

Divergent Paths for Tagrisso (Osimertinib) and Rociletinib for EGFR T790M Mutation-Positive NSCLC and Acquired Resistance: What Happened, and Where Are We Now?

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For patients with an activating EGFR mutation and who develop “acquired resistance”, the pattern of progression that occurs after a sometimes long period of good initial response to an oral EGFR tyrosine kinase inhibitor (TKI) like Tarceva (erlotinib), Iressa (gefitinib), or Gilotrif (afatanib), the evolving story of the treatment options has been a wild ride with several ups and a few downs. Over the last two years, several “third generation EGFR TKIs” with a strong affinity for EGFR activating mutations and, importantly, a different mutation called T790M, which is seen in 50-60% of patients with EGFR mutation-positive acquired resistance, but very low affinity for “wild type” (normal, non-mutated) EGFR molecules (which mediate the common, problematic side effects with EGFR TKIs, such as rash and diarrhea).  Given the very different paths that the two leading entrants – Astrazeneca’s Tagrisso (osimertinib, also previously known as AZD9291 and transiently as merelitinib) and Clovis’s rociletinib (also known as CO-1686) – it’s high time to review what has happened to get to where we are now.

The annual ASCO meeting in 2014 included very prominent presentations about these agents (Tagrisso and rociletinib, respectively), at that point still in early trials with several dozen patients each, that showed both agents had marked activity against the subset of patients with acquired resistance whose tumors test positive for T790M. At that time, AZD9291, which ultimately became osimertinib and then branded as Tagrisso, was a half-step ahead in terms of a slightly larger number of patients tested, but both agents were very promising for a population in which alternative treatment options other than standard chemotherapy. Though some concerns were raised about hyperglycemia (high blood sugar levels) in patients on CO-1686, my view at the time was that in people facing the threat of an advanced cancer, taking pills or even possibly insulin to manage blood sugar levels wasn’t likely to be a major issue if it worked effectively. Like many other lung cancer specialists and general oncologists alike, my perspective was that access to either agent would be a welcome opportunity for patients eligible for an accessible clinical trial. 

These two agents have been widely studied in a range of global trials as they continued their footrace over the next 12-18 months. In August, 2015, the remarkably early results with these two agents was featured in back to back articles (on Tagrisso and rociletinib, respectively in the prestigious New England Journal of Medicine.

But since that time, the paths of those two agents have diverged remarkably.  Tagrisso became FDA-approved in November, 2015 after continuing to demonstrate a response rate of significant tumor shrinkage in about 55-60% of T790M-positive recipients and up to 90% experiencing “disease control” that includes less significant shrinkage and stable disease. Importantly, these responses tend to last for many months to a year or longer, and this longitudinal treatment has been associated with a very low risk of significant side effects, with most patients experiencing either no issues or a rash and diarrhea that is so minimal that, in my experience, they haven’t felt warrants a hint of complaint.  The value of offering Tagrisso for T790M-positive acquired resistance has really changed the standard of care for EGFR mutation-positive patients with progression, making it instantly critical to seek and hope to find a T790M mutation, with a valuable subsequent treatment option to pursue before moving on to other options routinely offered for advanced NSCLC.

The path of rociletinib has been very dramatic over the past 6-7 months, but unfortunately it has been in a downward trajectory. Though provocative work over the past year has shown that this agent could work well in patients with T790M detected even in plasma, perhaps obviating the need for repeat tissue biopsies, the side effect profile with further use made it arguably a less attractive option than Tagrisso.  In my own experience, the constellation of nausea, diminished appetite, and diarrhea could create a cascade of weakness and misery that required aggressive dose reductions in a significant minority of patients and an occasional patient expressing dramatically “if this is what I need to do to have my cancer respond, I’d rather die” (though other patients certainly tolerate it better). But the biggest hit came in November, 2015, when the FDA reported that it was planning to delay a decision on potential approval of rociletinib after updated information revealed that the response rate reported to rociletinib of 59% was actually an “unconfirmed” response rate that dropped to about half that rate when looking only at confirmed responses (though the latest published update pegs response rate at 45%). The fortunes for rociletinib, along with Clovis’s stock price, dropped like a rock.

Tailspin

 Since then, clinical trials with rociletinib have continued on, and the FDA has continued its review process for the drug. The Oncology Drug Advisory Committee (ODAC) to the FDA, eviewing the evidence in April, came back with a 12-1 vote against approval until results from a randomized trial of rociletinib vs. chemotherapy be completed and demonstrate a clear benefit for rociletinib.  Then, in early May, Clovis announced very suddenly that the FDA, which almost always followed ODAC’s thoughtful recommendations, had notified the company that the FDA would not be offering an approval until further data supported its use. In that same press release, Clovis announced that it was terminating all trials with rociletinib (and was laying off 35% of its employees).

One important issue that the potential approval of rociletinib raised was the question of whether it should be compared to osimertinib or not. Technically, rociletinib didn’t need to be better than its predecessor to the market in the same space, but it is hard to determine what value there is in offering an agent with seemingly less activity and worse side effects than an agent we already have available. This issue of a strong incumbent will be a critical factor for other would-be challengers, further behind in development, which enter a world with Tagrisso as an entrenched, effective therapy in this setting, so how might other agents fit in?

A key relevant question here is how similar or dissimilar these agents truly are. One might well assume that there is a great deal of “cross-resistance” to drugs in the same family, as we see minimal activity of one first or second generation EGFR TKI after another (such as trying Tarceva after Iressa, or Gilotrif after Tarceva), just as you wouldn’t expect to have many people wildly excited about having a Pepsi after drinking a two liter bottle of Coke. But in fact, Dr. Lecia Sequist and colleagues from Massachusetts General Hospital recently reported that they have seen several cases of tumor shrinkage or prolonged stable disease on Tagrisso – including in the brain as well as other parts of the body — in patients who had demonstrated clear progression on rociletinib previously. As someone who had patients progressing on rociletinib in clinical trials, I followed this lead and have treated several of my patients with Tagrisso and also seen several very encouraging responses after progression on rociletinib. This is an important finding for patients in this setting who may benefit.

These advances are very significant, but we must still acknowledge the work that still needs to be done. Third generation EGFR TKIs may prove to offer meaningful benefits to the 40-50% of patients with T790M-negative acquired resistance, or we may need to search for better options elsewhere. It will also represent a great breakthrough if we can do repeat biopsies to check for T790M or other mutations in circulating plasma of patients rather than be required to pursue invasive biopsies at several time points over the course of treatment.  Though we probably can’t predict future developments much better than we might have predicted the drama in this space over the past two years, I can predict that it will be eventful and that we will only have a better understanding of and treatments for EGFR mutation-positive NSCLC in the future.

What do you think of these developments?


GRACE Video

Rociletinib/Osimertinib for EGFR T790M-negative NSCLC

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GRACE Cancer Video Library - Lung

GCVL_LU-F13_Rociletinib_Osimertinib_EGFR_T790M-Negative_NSCLC

 

Dr. Jack West, Swedish Cancer Institute, reviews trial evidence for the efficacy of rociletinib and osimertinib for EGFR acquired resistance not driven by a T790M mutation.

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Transcript

For patients who have an activating mutation in their cancer known as EGFR we have several very good first line treatment options to consider. There are three leading contenders as oral targeted therapies that block EGFR and tend to work very well for patients with an EGFR mutation. These agents are known as Iressa (gefitinib), Tarceva (erlotinib), and Gilotrif (afatinib). These agents have a chance of shrinking the tumor in the range of 60% to 75% which is great, but unfortunately these responses do not last forever and on average, patients will develop progression of their cancer, so-called acquired resistance to this first line therapy, after something in the range of nine to 12 months — can be less, can be more.

The question is what to do when that occurs. Well, there are a couple of agents that have shown great promise and great activity, at least in the subset of patients who have a mutation, found at the time of this acquired resistance, that is known as T790M. And so we repeat a biopsy of an area of progressing cancer while patients are on and progressing on this first line EGFR inhibitor, and 50% or 60% will have this acquired resistance mutation known as T790M. For those patients, we standardly consider drugs like osimertinib and rociletinib, and I say standardly consider as if they’re commercially available, and they’re not yet, at this moment in late 2015, FDA approved but it is expected that both will be approved by the FDA based on their very good activity in the very near future, perhaps by the time you see this.

But these agents are best studied and have their greatest activity in the patients with a T790M mutation. So what about the patients who are still 40% or 50% of that population with progressing cancer on an EGFR inhibitor who don’t have a T790M mutation? It turns out that both of these agents have good activity, or at least some degree of activity, in patients who are T790M-negative. It doesn’t tend to be as long-lasting and the response rates tend to be lower, but the activity is certainly encouraging.

GCVL_LU-XXNN_Jack_West_Swedish_15_01

When you look at what’s called a waterfall plot that’s shown here of how patients respond, the bars going downward represent patients whose cancers have shrunk, and the ones that go upward are the ones whose cancers have progressed on a therapy. You can see that when we look at patients who received osimertinib, the AstraZeneca drug AZD9291, there is good activity in the majority of patients who receive this agent, even if they have no T790M mutation.

GCVL_LU-XXNN_Jack_West_Swedish_15_02

The same is true for rociletinib, the Clovis drug CO1686 — the waterfall plot shows that most of the bars do go down, and that a lot of patients receive a substantial benefit, even if they do not have T790M detected in their rebiopsied tumor.

So there are studies that are looking specifically at these agents in patients who are T790M-negative. A trial with rociletinib known as TIGER-3 is looking at patients who have received prior EGFR inhibitors like Iressa, Tarceva or Gilotrif, and have also received prior chemotherapy. These patients are then randomized to either receive rociletinib or a standard chemotherapy as a single agent, and there are several that your doctor can choose from. This trial will be looking at which patients do better depending on whether they get the targeted therapy or standard chemotherapy.

There is another trial being done with osimertinib in combination with an EGFR monoclonal antibody known as necitumumab, so a two drug combination being looked at in patients who are T790M-negative after progressing on a first line EGFR inhibitor. So both of these agents are being studied not just in patients with a T790M-positive cancer, but a T790M-negative cancer, and if you do have acquired resistance and are found to not have a T790M mutation, you might want to look into information about these trials to see if one might be a good choice for you.


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