Biotech Strategy Blog

Commentary on Science, Innovation & New Products with a focus on Oncology, Hematology & Cancer Immunotherapy

Posts from the ‘Imaging’ category

Cancer Immunotherapy will require personalized treatment based on the type of cancer you have, and the immune response your body has generated to the cancer.

Dr Holbrook Kohrt Stanford

Dr Holbrook Kohrt at Immunology 2015

The sadly missed and visionary Dr Holbrook Kohrt was very prescient when he told BSB in New Orleans back in May 2015:

“Today when I see a patient or you go to a cancer center, the first thing they ask is what type of cancer do you have? Most patients respond – breast cancer, a colon cancer – unfortunately we are not in position where patients can say I have a deficiency in my cytotoxic CD8 cells or I have overly active regulatory T cells.

I actually envision a day when patients will know both sites, they will know they have breast cancer and they’ll also know it’s because there’s a lack of effector cytotoxic CD8 T cells. That combination knowledge, of what your immune system is lacking and what tumor you have, that combination will allow you to identify what type of immunotherapy you need.

Patients may need CAR directed T cells and those will be for patients who have completely non-functional T cells themselves, no matter what therapy you give them, you’re not going to create those cells within the body, therefore you need to do it ex-vivo in a petri dish and give it back to them.

Other patients may have T cells that just need to be turned on and so all they need is a checkpoint modulator and that combination is going to be effective enough for them.

So it’s this dual diagnosis, diagnosing their immune system and diagnosing their tumor that’s going to allow us to identify one, two, or three therapies that’s going to be the right cocktail.” 

See post: Holbrook Kohrt leads the way in Targeting CD137, you can also listen to excerpts on the Novel Targets Podcast: Episode 6: Stepping on the Gas

ICYMI do listen to the tribute to Dr Kohrt on the Novel Targets Podcast from two people who knew him at Stanford: Dr Ron Levy and Dr Dan Chen (@DanChenMDPhD). It’s at the start of Episode 11: Cancer Immunity Cycle.

Immunoscore® — a diagnostic test based on the immune profile of a patient is based on the pioneering work of INSERM scientist Dr Jérôme Galon.

Dr Jerome Galon at ASCO 2016

Dr Jérôme Galon at ASCO 2016

We are fans of his work, and interviewed him at the 2015 European Cancer Congress. See post: Immunosurveillance, Immunoscore & Personalized Cancer Immunotherapy – an interview with Jérôme Galon.

Over 10 years ago, Dr Galon’s research published in The New England Journal of Medicine and Science showed that the type, location and density of immune cells within a tumor predicts clinical outcome in early stage colon cancer.

These findings led to the development of an assay called Immunoscore® that’s based on an analysis of cytotoxic T cells, the ones that kill cancer.

In the process, it has led to a new way of classifying stage 2/3 colon cancer patients: those with a high Immunoscore® (good prognosis), and those with a low Immunoscore® (poor prognosis). Dr Galon’s work has shown that irrespective of whether you are MSI high or MSS, colon cancer prognosis correlates with Immunoscore.

Dr Bernard Fox at #AACR16

Dr Bernard Fox at AACR 2016

As we heard from Dr Bernie Fox (@BernardAFox) at AACR 2016. See post: AACR Cancer Immunotherapy Insights from Dr Bernard Fox, listen to excerpts on Novel Targets Podcast Episode 12: Of Mice and Men:

“What I teach the first year medical students is that if you have metastatic cancer, the only thing that makes a difference in your life is whether you’ve got your immune system turned on. If it’s not turned on, it doesn’t make a difference what you get, chemo, radiation, surgery, you aren’t going to do well.”

Immune response is key to outcome, which means that knowing what your immune profile is will be key to deciding which of the many immunotherapy options, either alone or combination will achieve the desired effect.

A large multinational phase 3 clinical trial sponsored by the Society for Immunotherapy of Cancer (@SITCancer) was set up to validate Immunoscore® as a biomarker in Stage 2 colon cancer.

Dr Galon and co-authors reported the results at ASCO 2016. See post: immunoscore validated as an important biomarker for colon cancer. He featured on the ASCO 2016 episode of the Novel Targets Podcast: Immunotherapy or Bust.

Immunoscore® is now being commercialised by Marseille based HalioDx(See post: HalioDx CEO Vincent Fert outlines commercial strategy for Immunoscore in US and Europe).

ciml40During a recent visit to the Marseille Immunopôle for #CIML40, I had the pleasure to do an impromptu tour of the HalioDx lab.

When listening/watching this, do bear in mind this was not a scripted tour, and also the people I spoke to were speaking English as a second language.

It’s not intended to be a definitive guide; if you are a patient you should talk to your doctor about any questions you have about diagnostic assays such as Immunoscore.  At the moment, it’s only available for research or clinical trial use, but HalioDx has plans to make the assay commercially available on the US and Europe.

The company has more information on their website and also recently published a paper in the Journal for Immunotherapy of Cancer (open access) that describes how the test is done in more scientific detail.

In the meantime, subscribers can login to join me for a lunch-time tour, or you can purchase access below. The audio-slideshow tour was for several weeks open access and available to all, but is now for subscribers only:

Abiraterone Acetate Pre-Chemotherapy ASCO 2012Men with advanced prostate cancer want to know “if I take this drug, will I live longer?” Unfortunately, for abiraterone acetate (Zytiga®) in the pre-chemotherapy setting i.e for asymptomatic or mildly symptomatic men, doctors will only be able to say, “maybe” and tell the patient there is a strong trend towards an overall survival (OS) advantage.

You can read my Xconomy article published yesterday, on why I think it was a mistake for the abiraterone acetate COU-AA-302 trial (302 trial) in chemotherapy-naïve (pre-chemo) men to be stopped early.  The results were presented on Saturday at the American Society of Clinical Oncology (ASCO) meeting in Chicago.

Understanding the Lan-DeMets alpha spending function with O’Brien-Fleming boundary based on number of death events observed is challenging for non-experts.

However, the bottom line is that the 302 trial failed to meet the pre-specified hazard ratio for stopping early, and by so doing it failed to meet one of its co-primary endpoints. This is disappointing because the trial most likely only needed another 92 deaths to occur before it would have reached significance, and this would have occurred in a matter of months.

The co-primary endpoint of radiographic progression free survival (rPFS) was, however, met in the 302 trial. Whether rPFS reflects tangible clinical benefit is unknown.  The FDA have (to my knowledge) not approved a prostate cancer drug on the basis of rPFS , overall survival remains the regulatory standard.

I also learnt for the first time at ASCO about the problem of bone flare in patients receiving abiraterone. Charles Ryan, MD who presented the 302 data, discussed this is an ASCO educational session on prostate cancer imaging.

Bone scan flare is a spurious, “worsening” bone scan in the context of clinical response that reflects increased intensity of lesions, not new lesions.  In other words a brighter image on a bone scan may not represent disease progression.

In a previously published study, Dr Ryan showed a 43% incidence (10/23) of bone flare with abiraterone.  He advised attendees at the ASCO 2012 educational session to “look for, and CONFIRM new lesions before calling progression based solely on bone scans.”

Although the rPFS data for the COU-AA-302 trial was read centrally, and is therefore presumed to be more reliable as a result, I would have welcomed more discussion on the extent rPFS correlates with survival following the COU-AA-302 data presentation at ASCO.  I expect the Oncologic Drugs Advisory Committee (ODAC) will vigorously discuss this in more detail when Johnson & Johnson seek a pre-chemotherapy indication for abiraterone based on the COU-AA-302 data.

Bearing in mind overall survival has been the de facto standard in advanced prostate cancer, it will be interesting to see how the FDA and ODAC will view what is essentially a failed trial with a non-significant OS.  Will precedent be broken, opening the floodgates for future sponsor submissions based on PFS?

Update January 24 2013: FDA & EMA approve Zytiga Pre-Chemo in CRPC

With little fanfare and no ODAC, the FDA issued a press release on December 10, 2012 announcing that abiraterone acetate (Zytiga) had received approval “to treat men with late-stage (metastatic) castration-resistant prostate cancer prior to receiving chemotherapy.”

The press release states: “The FDA reviewed Zytiga’s application for this new indication under the agency’s priority review program. The program provides for an expedited six-month review for drugs that may offer major advances in treatment or provide a treatment when no adequate therapy exists.

The fact that there was an unmet need for prostate cancer treatments prior to chemotherapy was clearly key to their decision making. The press release notes that “patients who received Zytiga had a median overall survival of 35.3 months compared with 30.1 months for those receiving the placebo.”

However, the FDA in their carefully worded press release make no mention of the fact that the difference of 5.2 months in median overall survival failed to reach the pre-specified value for statistical significance.

In other words, although JNJ have expanded the label for abiraterone to include the pre-chemo indication, they cannot make the claim that taking abiraterone prior to chemotherapy definitely results in men living longer (overall survival). All we can say is that the data was trending towards a statistically significant overall survival advantage. To many this may seem academic, but overall survival remains the benchmark that drives cancer drug development and by which treatment effectiveness is judged.

As I noted in my post from ASCO 2012 for Xconomy, most likely statistical significance for overall survival would have been reached in a few months, which is why I and others thought the trial had been stopped too early. I would be surprised if other companies follow JNJ’s strategy, and expect Medivation will seek to show a significant overall survival advantage for enzalatumide (Xtandi) in their pre-chemotherapy PREVAIL trial.

Johnson & Johnson announced on January 11, 2013 that abiraterone has also received approval in the European Union for the pre-chemotherapy prostate cancer indication following a positive recommendation from the Committee for Medical Products for Human Use (CHMP) of the European Medicines Agency (EMA).

It will be interesting to see if there is any new data in the updated interim analysis for the COU-AA-302 trial (abiraterone pre-chemo) that will be presented at the 2013 ASCO Genitourinary Cancers (ASCO GU) symposium in Orlando next month.

 

EAU-2012-Congress-Media-Briefing-Professor-Jelle-Barentsz“The Mannogram – Yes we scan” Jelle Barentsz, Professor of Radiology at Radbound University, Nijmegen, The Netherlands told the assembled media at the recent European Association of Urology (EAU) annual Congress in Paris.

Professor Barentsz described how advances in magnetic resonance imaging (MRI), and in particular multi-parametric MRI (Mp-MRI) offer the potential for the improved detection and characterization of prostate cancer.

In the same way there is a mammogram that women use for breast cancer screening, Professor Barentsz raised the possibility that using magnetic resonance imaging, men could have a mannogram to screen and diagnose prostate cancer.

Some of the advantages of multi parametric MRI he highlighted include:

  • Prediction of tumor aggression
  • Prediction of low vs intermediate or high grade prostate cancer correctly in 95% of men in a trial as compared to 54% with TRUS (trans-rectal ultrasound guided) biopsy
  • In cases where there was a negative TRUS biopsy initially, mp-MRI and MR guided biopsy detected prostate cancer in 41% (108/265 of trial participants), with 87% of the prostate cancer detected being significant.

It is beyond the scope of this post to go into the physics of multi-parametric MRI or discuss in more detail the imaging trial data on which the above conclusions are based.  However, for those interested in this area, I have included details of some of the references Professor Barentsz kindly provided at the end of the post.

Why do we need new techniques for prostate cancer diagnosis? 

During their lifetime 1 in 6 men will be clinically diagnosed with prostate cancer.  There are 899,000 new cases and 258,000 deaths per year in Europe.

The current diagnostic tools of digital rectal examination (DRE), serum prostate specific antigen (PSA) and trans-rectal ultrasound guided (TRUS) biopsy have a number of limitations for prostate cancer detection.

This includes a lack of specificity (PSA = 36%), insensitivity (DRE = 37%) or failure to detect cancer due to sampling error with TRUS biopsy (more than 20% of cancers are not detected on first biopsy).

The result is that we end up with large numbers of men with elevated men or rising PSA, who have repeat biopsies. This comes at a high cost to health care providers, the uncertainty of diagnosis and the discomfort that comes with a TRUS biopsy (TRUS-Bx).

Many men undergo diagnostic procedures only to find they don’t have prostate cancer. One of the key issues in the prostate cancer screening debate is this unacceptable harm/benefit ratio.

Prostate biopsy to confirm cancer diagnosis is an invasive procedure as Professor Jenny Donovan, Head of the School of Social  and Community Medicine, at the University of Bristol told the EAU Congress.

In a plenary session, Prof Donovan described some of the initial findings from the PROBE (Prostate Biopsy Effects study), which looked at 1,147 men who received a TRUS-Bx.

“The majority of men tolerated biopsy reasonably well – over 60% experience minor symptoms. However, around one third experience symptoms that bothered them,” she said.

Professor Donovan went on to give examples of some of the feedback on the biopsy experience that researchers obtained:

“I found it incredibly painful and distressing – biopsy with a nail gun,” one man in the PROBE study said.

Data presented by Professor Donovan showed that after the procedure, 11% of men would not want another biopsy (this rose to 20%) seven days later.

Magnetic Resonance Imaging Guided Biopsy may offer benefits

Given the discomfort that many men experience with TRUS biopsy, and the fact a negative biopsy does not automatically mean no cancer (there’s a risk of sampling error), the use of MR guided biopsy may offer significant benefits.

One is that instead of 12 cores being sampled by the TRUS-Bx, only 2 cores are obtained using the MR guided biopsy technique that Professor Barentsz described.

Personally, I would prefer to have two precise cores samples taken from me through imaged based guidance, than have a TRUS biopsy that is like a nail gun that shoots in 12 sampling rods into the target area of the prostate.  This would be like the difference between a sniper rifle and a blunderbuss, metaphorically.

One of the practice implications of this is that radiologists may end up performing MR guided biopsies instead of urologists performing TRUS biopsies.

Urologists in private practice or those who are paid per procedure may not be happy about the practice changing implications that may result.

The MR imaging research that Professor Barentsz described at EAU is not without its limitations and one concern is the reproducibility of advanced imaging techniques outside of an expert university or academic setting.  I put this question to Professor Barentsz in the media briefing and have included an excerpt of his reply that you can listen to:

According to Professor Barentsz, the imaging techniques for MR guided prostate biopsy are readily reproducible outside the academic environment with guidelines already in place for standardized acquisition protocols and structured interpretation of results.

We are now at the point that the standardization of prostate MRI as well as the standardization of reporting with all kind of computer assistance is a fact and not fiction anymore,” said Barentsz.

The European Society of Urogenital Radiology (ESUR) recently published MR guidelines, that include a structured reporting system, called PI-RADS (prostate imaging, reporting, and data system).  This has been adopted in the United States by the American College of Radiology (ACR).

Before men with prostate cancer can expect to see these advanced imaging techniques used outside of expert centers, however, urologists and radiologists will need to agree on the benefits they offer and adapt their practice accordingly. Urologists may be reluctant to move away from TRUS biopsy, so it is likely widespread implementation will take some time and require education, and explanation of the evidence based medicine that supports the proposed change in practice.

The conclusion from Professor Barentsz’s EAU presentation is that imaging looks likely to play an increasing role in the diagnosis of prostate cancer.

It will be an exciting area to watch. The idea of a Mannogram has the potential to become a reality that would benefit the 1 in 6 men who will be diagnosed with Prostate Cancer during their lifetime.

References

ResearchBlogging.orgHambrock, T., Somford, D., Huisman, H., van Oort, I., Witjes, J., Hulsbergen-van de Kaa, C., Scheenen, T., & Barentsz, J. (2011). Relationship between Apparent Diffusion Coefficients at 3.0-T MR Imaging and Gleason Grade in Peripheral Zone Prostate Cancer Radiology, 259 (2), 453-461 DOI: 10.1148/radiol.11091409

Hoeks, C., Schouten, M., Bomers, J., Hoogendoorn, S., Hulsbergen-van de Kaa, C., Hambrock, T., Vergunst, H., Sedelaar, J., Fütterer, J., & Barentsz, J. (2012). Three-Tesla Magnetic Resonance–Guided Prostate Biopsy in Men With Increased Prostate-Specific Antigen and Repeated, Negative, Random, Systematic, Transrectal Ultrasound Biopsies: Detection of Clinically Significant Prostate Cancers European Urology DOI: 10.1016/j.eururo.2012.01.047

Barentsz, J., Dickinson, L., & Sciarra, A. (2011). Re: Axel Heidenreich. Consensus Criteria for the Use of Magnetic Resonance Imaging in the Diagnosis and Staging of Prostate Cancer: Not Ready for Routine Use. Eur Urol 2011;59:495–7 European Urology, 60 (1) DOI: 10.1016/j.eururo.2011.03.013

Hambrock, T., Hoeks, C., Hulsbergen-van de Kaa, C., Scheenen, T., Fütterer, J., Bouwense, S., van Oort, I., Schröder, F., Huisman, H., & Barentsz, J. (2012). Prospective Assessment of Prostate Cancer Aggressiveness Using 3-T Diffusion-Weighted Magnetic Resonance Imaging–Guided Biopsies Versus a Systematic 10-Core Transrectal Ultrasound Prostate Biopsy Cohort European Urology, 61 (1), 177-184 DOI: 10.1016/j.eururo.2011.08.042

Barentsz, J., Richenberg, J., Clements, R., Choyke, P., Verma, S., Villeirs, G., Rouviere, O., Logager, V., & Fütterer, J. (2012). ESUR prostate MR guidelines 2012 European Radiology, 22 (4), 746-757 DOI: 10.1007/s00330-011-2377-y

One of the challenges of the next decade in cancer research will be targeting cancer metabolism; imaging is likely to play a key role in drug development.

NMR-image-of-brain-gliomaThe cover of the January 11 online issue of Science Translational Medicine (STM) shows a brain tumor (glioma) in red, detected using non-invasive nuclear magnetic resonance imaging that highlights cancer metabolism.

In a paper published in STM, Andronesi and colleagues from Harvard & other Cambridge, MA institutions (including Agios Pharmaceuticals – more on them later), showed that excess production of the metabolite 2-hydroxyglutarate (2HG) could be used as a biomarker for a subset of glioma.

The subset this metabolic biomarker identified, were those patients with mutations of the isocitrate dehyrogenase gene (IDH1), present in 86% of the grade II & III gliomas and secondary glioblastomas.

Agios Pharmaceuticals founded by eminent cancer researchers, Lewis Cantley, Tak Mak and Craig Thompson is targeting the IDH1 and IDH2 metabolic pathways.

They have shown that mutations of the metabolic gene IDH1 are consistent with that of a cancer-causing oncogene.  Interestingly, Agios notes on their website that IDH1 and IDH2 mutations have also been seen in acute myeloid leukemia (AML).

What makes 2HG a functional biomarker for glioma is its correlation with survival.  2HG accumulates in the brains of patients with IDH1 mutations. These patients have a greater survival than those with wild-type IDH1 gliomas.

Developing a drug that targets cancer metabolism in the brain is not easy. NMR imaging of the 2HG in the brain will help researchers non-invasively follow the effects of inhibitors of mutated IDH1. This is particularly important given that, according to Andronesi et al,  “no report exists about increased D-2HG in the blood, cerebrospinal fluid, or urine of glioma patients with IDH1 mutations.”

The January 11 online issue of STM, also contains another paper on the detection of 2HG using NMR. Elkhaled and colleagues from UCSF report a technique of proton high-resolution magic angle spinning spectroscopy.  Their data confirms the potential of 2HG as a surrogate marker of patient survival.

Cancer metabolism as a drug development target is an area I expect we will see more of in the next ten years.  Key to success will be the ability to identify biomarkers with which to assess and monitor the success of drug candidates.

The identification of 2HG as a biomarker for IDH1 in glioma patients shows that cancer metabolism is an area of potential for drug development.

One cloud on the horizon for Agios Pharmaceuticals is, however, the filing of a lawsuit late last year by the Abramson Cancer Institute of the University of Pennsylvania. This alleges that Craig Thompson concealed the start-up of Agios while working for Penn, and in essence took the intellectual property of the University to the company. The merits of this claim have yet to be decided.

References

ResearchBlogging.orgAndronesi, O., Kim, G., Gerstner, E., Batchelor, T., Tzika, A., Fantin, V., Vander Heiden, M., & Sorensen, A. (2012). Detection of 2-Hydroxyglutarate in IDH-Mutated Glioma Patients by In Vivo Spectral-Editing and 2D Correlation Magnetic Resonance Spectroscopy Science Translational Medicine, 4 (116), 116-116 DOI: 10.1126/scitranslmed.3002693

Elkhaled, A., Jalbert, L., Phillips, J., Yoshihara, H., Parvataneni, R., Srinivasan, R., Bourne, G., Berger, M., Chang, S., Cha, S., & Nelson, S. (2012). Magnetic Resonance of 2-Hydroxyglutarate in IDH1-Mutated Low-Grade Gliomas Science Translational Medicine, 4 (116), 116-116 DOI: 10.1126/scitranslmed.3002796

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Photoimmunotherapy (PIT) that uses a near-infrared (NIR) dye conjugated to monoclonal antibodies (mABs) that target epidermal growth factor receptors (EGFR) is a new type of molecular-targeted cancer therapy that appears to offer considerable promise.

Research by Makoto Mitusnaga and colleagues from the Molecular Imaging Program at the National Cancer Institute (NCI) was published recently in Nature Medicine. This paper is well worth reading if you have an interest in this area.

The NCI researchers developed a:

“mAb-based photosensitizer that is activated by NIR light for targeted PIT only when bound to the target molecule on the cancer cellular membrane.”

I think this is exciting research because unlike conventional photodynamic therapy that also damages normal tissue, photoimmunotherapy kills only antibody-bound cancer cells with no normal tissue damage:

“Further, because this agent also emits a diagnostic fluorescence, it can be used to direct the application of light to minimize exposure to nonrelevant tissues and to noninvasively monitor any therapeutic effects of excitation light.”

You can read more in the Nature Medicine paper about this exciting research that may offer an innovative new drug delivery mechanism for targeted cancer therapies.

ResearchBlogging.orgMitsunaga, M., Ogawa, M., Kosaka, N., Rosenblum, L., Choyke, P., & Kobayashi, H. (2011). Cancer cell–selective in vivo near infrared photoimmunotherapy targeting specific membrane molecules Nature Medicine DOI: 10.1038/nm.2554

The recent AACR-NCI-EORTC Molecular Targets and Cancer Therapeutics international conference in San Francisco was an informative meeting.

What I particularly liked was the strategic overview that took place in many of the plenary sessions.

As an example, Johann de Bono, Professor of Experimental Cancer Medicine at The Institute of Cancer Research/The Royal Marsden in London highlighted the potential drug development targets based on prostate cancer biology:

  • Androgen Receptor (AR)
  • Heat Shock Proteins (Hsp)
  • Signaling: HER3, MET, IGF-1R, CCL2, IL-6, Src
  • PI3K/AKT/TOR signaling
  • PARP and BRCAness
  • Estrogen receptor (ER)
  • c-MYC & CHK1

His presentation discussed the possible therapeutic approaches, and complexity involved in developing novel targeted therapies for prostate cancer.

This is something that I expect we will hear more of at the AACR special conference on Advances in Prostate Cancer Research early next year.

In particular, de Bono discussed drug development strategies to target androgen receptor signaling, and some of the future challenges including:

  • Proving to the regulatory authorities that circulating tumor cell (CTC) count falls are a robust immediate endpoint of overall survival
  • Developing improved imaging for bone metastases

As a side note, there were several posters for cabozantinib (XL184) at the meeting (available on the Exelixis website), including preliminary research on computer-aided quantitative bone scan assessment.

However, as de Bono mentioned in his presentation, “diffusion weighted MRI shows hot spots not detected by bone scans.”

2010 and 2011 were good years for prostate cancer drugs, and with new approvals for MDV3100 and radium-223 (Alpharadin) expected, 2012 is set to be another “grand cru” year, to paraphase Bertrand Tombal.

If you were not able to make it to San Francisco for the Molecular Targets and Cancer Therapeutics conference, webcasts of many sessions will be available on the AACR site.

 

Cancer Research UK issued a press release today about a phase 2 trial (GALA-5) in glioblastoma that caught my attention.

The trial, led by Colin Watts from the University of Cambridge, will treat patients with 5-Amino-Levulinic Acid (5-ALA), a metabolic marker of malignant glioma cells.  5-ALA is preferentially taken up by brain tumor cells and then converted into a strongly fluorescing porphyrin.

This conversion by the body of 5-ALA to a fluorescent chemical, shows the location of the glioblastoma when imaged under ultraviolet light.

Flourescent-5-ALA-Glioblastoma-Dr Colin Watts

The practical application of this is that it allows better identification of the tumor margins and avoids the removal of unnecessary brain tissue.

The use of fluorescent imaging to aid surgery is also being investigated in other tumors. Sally Church on Pharma Strategy Blog recently wrote about the use of folate receptor alpha fluorescence imaging in ovarian cancer.

It will be interesting to see how the GALA-5 phase 2 clinical trial in glioblastoma progresses.  The fluorescent imaging technology while promising is not without its pitfalls and potential risks.

As Jörg-Christian Tonn and Walter Stummer note in Vol 55 of “Clinical Neurosurgery (2008) some of the pitfalls with fluorescence-guided resection using ALA include:

  • Problem of overhanging margins i.e. inability to see all the tumor in the field of vision
  • Cysts leading to collapse of parts of the tumor with the result that areas are missed
  • Wrongly placed craniotomies preclude complete resection of contrast-enhancing tumor
  • Some cases of gliosarcoma show only modest fluorescence accumulation
  • Delay in drug administration may lead to less than optimal fluorescence
  • Exponential decrease in light with growing distance to fluorescent tissue, resulting in weak fluorescence intensity

No doubt many of the above issues will be controlled for in the GALA-5 trial. The challenge with imaging techniques is, however, in consistency and reproducibility outside of experienced clinical research investigation sites.

It will be interesting to see whether the potential pitfalls can be overcome such that this promising experimental imaging becomes routine in glioblastoma surgery.

Story Source: BBC Health

The Oncologist Journal of the Society for Translational Oncology (STO) has published a video recording on prostate cancer that is well worth watching for those with an interest in this area.

At their Sept 8, 2011 CME symposium held in Belfast, a roundtable was held entitled “Prostate Cancer: Progress & Promise.”

Moderated by Bruce A. Chabner (Mass General/Harvard), the panelists were Joe O’Sullivan (Queen’s University, Belfast), Johann De Bono (The Institute for Cancer Research) and David Waugh (Queen’s University, Belfast).

Professor de Bono in the video comments that”

“with regards to our dream of eventually treating men with prostate cancer without castrating them, which must be our ultimate goal and curing them of cancer. I think we will have to focus on for example drugs targeting ERG or ERG signaling.”

Chabner then asks the good question of whether ERG is a druggable target?

To which De Bono replies that you can drug ERG by inhibiting PARP and references a paper by the Chinnaiyan group published in the May 2011 issue of Cancer Cell.

PARP inhibition represents an interesting area of prostate cancer research.

If you would like to know more, Sally Church, PhD has written about this on Pharma Strategy Blog.  See posts on “TMPRSS2: ERG may be a more useful marker than PSA in prostate cancer” and “Personalized Therapy for Prostate Cancer – is it possible?

In the STO video, De Bono discusses why he would like to replace bone scans in prostate cancer with another imaging modality that more accurately reflects the activity of the disease. Future possibilities include use of diffusion weighted magnetic resonance imaging and novel PET tracers.

There’s also a good discussion about Alpharadin for those interested in some anecdotal commentary on experiences with it.

Another notable comment by De Bono is his belief that “taxanes work in prostate cancer primarily by targeting androgen receptor signaling.” Taxanes have typically been thought to target mitosis.

De Bono goes on to say that clinical trial data being submitted for publication shows that patients who are refractory to abiraterone, are also refractory to docetaxel when they progress on it.  The suggestion is that there may be cross resistance between abiraterone and taxanes with a subgroup of patients who just don’t do well on androgen receptor (AR) targeting drugs.  The reason for this isn’t yet clear.

A new phase 2 clinical trial is starting soon that will look at the sequencing of abiraterone and cabazitaxel.  One group will receive abiraterone followed by cabazitaxel, the other cabazitaxel followed by abiraterone.

The Belfast STO symposium was the second in a three part series. The next one will be held during ASCO GU in San Francisco next year.

Another potentially useful meeting in this area is the February 2012 AACR workshop on “Advances in Prostate Cancer Research” chaired by Arul Chinnaiyan & Charles Sawyers.

Prostate cancer remains an exciting therapeutic area to watch with tremendous progress and promise of late.

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