Edit 10 Jan 2019: RadioMedix and Curium Announce FDA Fast Track Designation For 64Cu-Dotatate. Read more byclicking here.
Curium and RadioMedix Inc. announce an exclusive agreement to develop and commercialize 64Cu-Dotatate, an investigational positron emission tomography (PET) diagnostic agent for patients with Neuroendocrine Tumors (NETs). RadioMedix is currently engaged in Phase III clinical trials of the agent and expects to file a New Drug Application with the Food and Drug Administration in 2019. This partnership builds on the initial development work conducted by RadioMedix and will benefit from Curium’s regulatory, manufacturing, distribution, and commercial expertise. The radionuclide is not new, it’s been in use for some time, mainly in Denmark.
64Cu is a PET isotope that can be produced at a central location in quantities to meet the commercial needs of hospitals and imaging centers without the supply limitations of nuclear generator-based PET isotopes,” said Ebrahim Delpassand, MD, CEO of RadioMedix. “Once approved, 64Cu-Dotatate will be available to patients in medical centers with PET capability across the country. This will address the shortage or lack of availability of somatostatin analogue PET agents that we are currently experiencing in many parts of the U.S.”
Ga68 PET Shortages explained
This statement is in relation to the current shortage of Ga68 PET radionuclide. For those not aware, the Society of Nuclear Medicine and Molecular Imaging (SNMMI) has written a letter to the FDA about ongoing shortages of generators that produce gallium-68 (Ga-68), a radioisotope used regularly in medical imaging. The letter—available here.
The letter explains that Ga-68 is currently used to produce NETSPOT from Advanced Accelerator Applications (a Novartis company), which was approved in June 2016 to help treat neuroendocrine tumors (NETs) in adult and pediatric patients using PET. NETSPOT, however, is only approved using specific generators. And those generators are only approved for either 400 uses or one year, whichever comes first. This has led to shortages throughout the United States.
SNMMI notes some possible remedies for this shortage. For instance, “a temporary exemption to the 400-elution limit would have a major impact on NETSPOT capacity for patients,” according to the letter. In addition, using a wider variety of generators to produce NETSPOT or using cyclotron-produced gallium chloride are two other methods that could improve production in a relatively short amount of time. “Further discussion with the manufacturers is necessary,” the authors added.
Read more about Ga68 PET and its use in Neuroendocrine Cancer – click here. Worth also noting that RadioMedix is also involved in a number of NET related initiatives including:
1. Trials for a new type of PRRT called ‘Targeted Alpha-emitter Therapy (TAT) – I’ve written about this previously. Read my article here.
2. An exclusive distributor for the TM Isotopen Technologien München AG (ITM) PRRT product currently in trial. I wrote about this here.
How does 64Cu-Dotatate compare with Ga68 PET and Octreotide Scans?
To learn more about previous studies on 64Cu-Dotatate, here’s 2 articles published in the Journal of Nuclear Medicine which are a head to head comparison of 64Cu-Dotatate with Ga68 Dotatoc and with 111 Indium Octreotide (Octreoscan).
Conclusion: 64Cu-DOTATATE has advantages over 68Ga-DOTATOC in the detection of lesions in NET patients. Although patient-based sensitivity was the same for 64Cu-DOTATATE and 68Ga-DOTATOC in this cohort, significantly more lesions were detected by 64Cu-DOTATATE. Furthermore, the shelf life of more than 24 h and the scanning window of at least 3 h make 64Cu-DOTATATE favorable and easy to use in the clinical setting.
Conclusion: With these results, we demonstrate that 64Cu-DOTATATE is far superior to 111In-DTPA-OC in diagnostic performance in NET patients. Therefore, we do not hesitate to recommend implementation of 64Cu-DOTATATE as a replacement for 111In-DTPA-OC.
The shortage of Ga68 PET radionuclide caused by limitations of the generators in use is unfortunate. Reading the SNMMI letter, I think progress can be made downstream. However, the introduction of a new scanning agent could be useful as long as the trials prove its safety and efficiently and is comparable to current tools. There is no news of any plans to extend this potential new radionuclide outside the US but I suspect that would change following an FDA approval.
When I was offered my very first Ga68 PET/CT at a 6 monthly surveillance meeting in May 2018, I was both excited and apprehensive. Let me explain below why I had a mix of emotions.
I was diagnosed in 2010 with metastatic NETs clearly showing on CT scan, the staging was confirmed via an Octreotide Scan which in addition pointed out two further deposits above the diaphragm (one of which has since been dealt with). In addition to routine surveillance via CT scan, I had two further Octreotide Scans in 2011 and 2013 following 3 surgeries, these confirmed the surveillance CT findings of remnant disease. The third scan in 2013 highlighted an additional lesion in my thyroid (still under a watch and wait regime, biopsy inconclusive but read on….).
To date, my 6 monthly CT scans seem to have been adequate surveillancecover and all my tumour and hormone markers remain normal. I’m reasonably fit and well for a 62-year-old.
Then I ventured into the unknown
I wrote a comprehensive post about the Ga68 PET entitled “…. Into the unknown” – so named because that is how I felt at the time. It’s well-known that the Ga68 is a far superior nuclear scan to the elderly Octreotide type, showing much greater detail with the advantage of providing better predictions of PRRT success if required downstream. It has been a game changer for many and if you look below and inside my article, you will see statistics indicating just how it can ‘change the game’ in somatostatin receptor positive Neuroendocrine Cancer diagnostics and treatment.
The excitement of the Ga68 PET
I was going to get the latest ‘tech’ and thought it could be useful confirmation of what I already knew. I also felt lucky to get one, they are limited in UK and there has to be a clinical need to get access. I was excited because it might just rubber stamp the stability I’ve enjoyed for the past 5 or so years since my last surgery in 2012.
The apprehension of the Ga68 PET
I also felt apprehensive because of the ‘unknown’ factor with cancer, i.e. what is there lurking in my body that no-one knows about, and which might never harm me but this scan will light it up demanding attention. I was also apprehensive in case this more detailed scan found something potentially dangerous. As we know, NETs are mostly slow-growing but always sneaky. Of course, any new tumours found may not actually be new, they were just not seen until the Ga68 PET was able to uncover them. How annoying!
Was Ga68 PET a game changer for me?
Yes, I believe so. I’m now in the ‘bone met club’ and although that single metastasis has probably been there for some time, it’s not a ‘label‘ I was keen to add to my portfolio. It’s brought more light onto my thyroid issue and continues to indicate some issues above the diaphragm including what looks like a new issue around my left pectoral and lights up an existing issue in the clavicle lymph nodes (first pointed out via Octreotide scan in 2010).
It also formed part of an investigation into progression of my retroperitoneal fibrosis (initially diagnosed 2010 but potential growth spotted on recent surveillance CT). I may now need surgery to prevent kidney/bladder issues and/or radiation therapy to tackle the root cause (the latter is ruled out for now – Nov 2018)
It would appear I’m no longer a boring stable patient
The Ga68 PET Scan confirmed:
Bone Metastases. Report indicates “intense focal uptake“. It always amazes me that people can be thankful for having an extra tumour. I’m thankful I only have a single bone metastasis (right rib number 11). I had read so many stories of those who got their first Ga68 PET and came back with multiple bone metastases. I’ll accept one and add to my NET CV. I have no symptoms of this bone metastasis and it will now be monitored going forward. I’m annoyed that I don’t know how long it’s been there though!
Confirmation and better understanding of the following:
Thyroid lesion There is some uptake showing. A 2014 Biopsy of this lesion was inconclusive and actual 2018 Ga68 PET report infers physiological uptake. I’m already diagnosed hypothyroidism, possibly connected. (Edit – on ultrasound in Jan 2019, looks slightly smaller than previous check).
Left Supraclavicular Fossa (SCF) Nodes lighting up “intense uptake“. I’ve had an exploratory biopsy of the SCF nodes, 5 nodes removed negative. Nothing is ‘pathologically enlarged’ in this area. Monitored every 6 months on CT, annually on ultrasound. I had 9 nodes removed from the left axillary in 2012, 5 tested positive for NETs and this area did not light up. This whole area on the left above the diaphragm continues to be controversial. My surgeon once said I had an unusual disposition of tumours. (Edit: Nothing sinister or worryingly enlarged showing on Jan 2019 ultrasound – measuring 6mm).
Report also highlights left subpectoral lymph nodes which is new. The subpectoral area is very interesting as from my quick research, they are closer to the left axillary (armpit) nodes than they are to the SCF nodesI’m hoping to get an ultrasound of these in January at my annual thyroid clinic (Edit: nothing sinister showing on ultrasound in Jan 2019).
My known liver metastases lit up (remnant from liver surgery 2011) – not marked as intense though. The figure of 3 seems to figure highly throughout my surveillance scans although the PET report said “multiple” and predominately right-sided which fits.
Retroperitoneal area. This has been a problem area for me since diagnosis and some lymph nodes are identified (intense word not used). This area has been highlighted on my 3 octreotide scans to date and was first highlighted in my diagnosis trigger scan due to fibrosis (desmoplasia) which was surrounding the aorta and inferior venous cava, some pretty important blood vessels. I wrote an article on the issue very recently – you can read by clicking here. So this scan confirms there are potentially active lymph nodes in this area, perhaps contributing to further growth of the fibrosis threatening important vessels – read below.
I have learned so much about desmoplasia in the last week that I now fully understand why I had to have radical surgery to try to remove as much of the fibrosis as possible from the aortic area. You can read more about this in my article. Desmoplasia via fibrosis is still very much of an unknown and mystery condition in NETs.
I now know that my fibrosis is classed as clinically significant and according to the Uppsala study of over 800 patients inside my article, I’m in 5% of those affected in this way (2% if you calculate it using just the retroperitoneal area).
It appears this problem has come back with new fibrosis or growth of existing fibrosis threatening to impinge on blood vessels related to the kidneys and also my ureters (kidney to bladder urine flow).
I didn’t expect this particular problem – it was a bit of a shock. This is not a straightforward surgery. My hormone markers have been normal for 7 years and this just emphasises the importance of scans in surveillance.
Conventional Imaging is still important though
There’s still quite a lot of hype surrounding the Ga68 PET scan and I get this. However, it does not replace conventional imaging (CI) such as CT and MRI scans which still have their place in routine surveillance and also in diagnostics where they are normally at least the trigger for ‘something is wrong’. For the vast majority, a CT/MRI scan will find tumours and be able to measure reductions and progress in regular surveillance regimes. There are actually recommended usages for the Ga68 PET scan here. For example, it is not recommended for routine surveillance in place of CI.
In fact, the retroperitoneal fibrosishas appeared on every CT scan since diagnosis but the changes were highlighted on my most recent standalone CT and it triggered the Ga68 PET (although my new Oncologist did say I was due a revised nuclear scan). It’s not a ‘functional’ issue (although it is caused by functional tumours). In fact the fibrosis is not mentioned on the Ga68 PET because it is not lighting up – but the lymph nodes surrounding it are mentioned and they are under suspicious as being active.
Read a summary of all conventional scans and nuclear scans by clicking here.
I’ve since has meetings with my Oncologist and Surgeon and a treatment plan is underway. My surgeon explained it all in his wonderfully articulate and brilliant surgical mind. Fortunately it’s not really urgent but pre-emptive treatment will be required at some point as the consequences of kidney/bladder function are quite severe. It’s also possible that PRRT will be considered as a way to treat the tumours responsible for new and renewed growth of the fibrosis. I will keep my blog updated as things progress.
My game has changed, that’s for sure. I’m now entering a new phase and I’m waiting on details of my revised surveillance regime. However, at least my medical team and I now know what WE are dealing with and the risks vs benefits are currently being assessed. I’m heavily involved in that.
Cancer is a growth industry …literally! More people are being diagnosed than ever before. Fortunately, more people are surviving than ever before. This is against a backdrop of better awareness, better screening in the big population cancers, and to a certain extent better diagnostic tools, all of which is leading to earlier diagnosis.
So how does this affect Neuroendocrine Cancer?
According to the latest SEER database figures for Neuroendocrine Cancer, one reason for the 7 fold increase in incidence rates since the 1970s is all of those things above including better diagnostics. This has led to a revised set of epidemiological information in many countries that have made the effort to accurately update their cancer registries and there are consistent reports of incidence rates way beyond the recognised rare thresholds. Another piece of good news is that the increase in NET incidence is also due to earlier diagnosis. To sum that up – NETs is also a growth industry.
Combined with more awareness and education (including the important pathologists), more NETs than ever are being found, and many found earlier. However, it’s not party time yet because there remains far too many misdiagnoses due to the low population of the disease and the difficulty in diagnosing it. I want to focus on scanning (thus the title of the article). Whilst there are really important factors involved in a diagnosis, such as tumor and hormone markers, and biopsies (tissue is the issue), a scan is very frequently what triggers many deeper investigations to unearth a NET, i.e. if you can see it, you can normally detect it (whatever the ‘it’ is). And I include the widespread availability and increasing advances in endoscopy/ultrasounds/cameras which have also been instrumental in picking up many Gastrointestinal NETs.
The Gallium 68 PET Scan
There’s a lot of excitement about the Gallium 68 PET Scan since it was approved by the US FDA. It’s not new though and has been in use in several countries for some time. It’s a ‘nuclear scan’ and can often form part of what is known as a ‘Theranostic Pair’ (i.e. in conjunction with a therapy – read more here).
What does it do?
It comprises two main components – a PET scanning machine, and the use of a diagnostic imaging agent which is injected into the person undergoing the scan. Most machines have an inbuilt CT which forms part of the scan. The agent is a somatostatin analogue labeled radionuclide (Gallium 68) and basically the PET will then be used to see where the peptide/radionuclide mix ‘loiters’ (i.e. where there are concentrations of somatostatin receptors (SSTR) normally indicating ‘focal intense abnormality‘ of the type that is regularly found with NETs.
Imaging Agents. There are different agent variants, namely, DOTATATE, DOTATOC and DOTANOC. In USA, you may sometimes see this referred as NETSPOT which is more of a commercial label for the agent (NETSPOT is a DOTATATE). Ga68 PET or SSTR PET are common descriptors for the entire process regardless of the compound. Clearly the scan works best for those with ‘somatostatin receptor positive’ tumours.
These newer agents have several benefits over the elderly In111-pentetreotide (Octreotide scan), including improved detection sensitivity, improved patient convenience due to the 2-3 hour length of the study (compared to 2 or 3 days with Octreoscan), decreased radiation dose, decreased biliary excretion due to earlier imaging after radiotracer administration, and the ability to quantify uptake. The quantification of the uptake can help decide whether a patient is suitable for radionuclide therapy such as PRRT. Eventually, all Octreotide scans should be replaced with SSTR PET but it will take some time (and money).
Octreoscan vs Ga68 PET
To confirm the advantages of SSTR PET over Octreotide scans, a study comprising 1,561 patients reported a change in tumour management occurred in over a third of patients after SSTR PET/CT even when performed after an Octreotide scan. Worth pointing out that SSTR PET is replacing the ageing Octreotide scan and not conventional imaging (CI). You can see the recommended scenarios for use of SSTR PET in this article published by the Journal of Nuclear Medicine. The slide below is interesting, although it was a small study. However, you can see the treatment changes as a result of a Ga68 PET are quite striking.
Any pitfalls with Ga68 PET Scan?
When you look at the study data above, it looks like an excellent addition to the diagnostic and surveillance toolkit for NETs. However, one of the challenges with modern scanning equipment and techniques is the ability to correctly interpret the results – in my opinion, this is almost as important as the efficiency of the machines and radionuclides. This requirement has been acknowledged in many articles and I particularly like this technical paper from a very experienced nuclear medicine physician Professor Michael Hofman from the Centre for Cancer Imaging at the Peter MacCallum Cancer in Melbourne. I had a chat with Professor Hofman who added that this is a very sensitive scan, so often picks up “new” disease, which isn’t really new, just never identifiable on standard imaging. However, there’s an excellent section on pitfalls in interpretation and I’m quoting an abstract below.
“Although GaTate PET/CT is a highly sensitive and specific technique for NETs, the attending physician or radiologist must be aware of various physiologic and other pathologic processes in which cellular expression of SSTR can result in interpretative error. Most of these processes demonstrate low-intensity and/or nonfocal uptake, in contrast with the focal intense abnormality encountered in NETs. Causes of interpretative pitfalls include prominent pancreatic uncinate process activity, inflammation, osteoblastic activity (degenerative bone disease, fracture, vertebral hemangioma), splenunculi or splenosis, and benign meningioma.”
“The highest-intensity physiologic uptake of GaTate is seen in the spleen, followed by the adrenal glands, kidneys, and pituitary gland”
It follows that failure to interpret nuclear scans alongside the patient’s clinical history can sometimes result in two big issues for patients:
1. Unnecessary worry when ‘something’ shows up which is actually a false positive.
2. Something which leads to irreversible treatment when it is was not required.
Just imagine something which is 40 times better than current PET scan technology? That’s what the scientists are working on now. Here’s an example called “EXPLORER“. You can update yourself here. The issue of interpretation will be even more difficult when the new generation of scans appear. There’s an excellent article from Cancer Research UK talking about the modern phenomenon called ‘overdiagnosis’ – readhere
Lanreotide and Octreotide and timing the scan?
From the same technical document referred above, here’s an extract (updated to include Lanreotide). “Uptake at physiologic and pathologic sites may change in patients who undergo concomitant short- or long-acting somatostatin analog therapy, which competes with the radiotracer for bioavailability. We generally discontinue short-acting octreotide for 12–24 hours and perform imaging in the week before the next dose of long-acting Octreotide/*Lanreotide, which is typically administered monthly“. More evidence behind the reason behind this issue can be found here. *added by the author for completeness.
Having my first Ga68 PET Scan after 8 years of living with NETs?
When I was offered my very first Ga68 PET/CT at my recent 6 monthly surveillance meeting, I was both excited and apprehensive. I was diagnosed in 2010 and my staging was confirmed via an Octreotide Scan pointing out two further deposits (one of which has since been dealt with). I’ve had two further Octreotide Scans in 2011 and 2013 following 3 surgeries. The third scan in 2013 highlighted my thyroid lesion – still under a watch and wait regime. So far, my 6 monthly CT scans seemed to be adequate surveillance cover and my markers remain normal.
I’m apprehensive because of the ‘unknown’ factor with cancer – what is there lurking in my body that no-one knows about and which might never harm me.
I’m excited because it might just confirm that there is nothing new to worry about.
However, I’m both excited (morbidly) and apprehensive because the scan might find something potentially dangerous. As we know, NETs are mostly slow growing but always sneaky. That said, at least I will know and my medical team will know and be able to assess the risk and decide on a course of action.
Doing the Scan
On 5th June 2018, I attended a very experienced Ga68 PET establishment called Guys Cancer Centre in London. I arrived and was immediately taken under the wing of the nuclear medicine guys who asked me fairly in depth questions about my clinical background. They then inserted a cannula ready for the injection of the radiolabelled tracer. I was then installed in the ‘hot room’ where they injected the radionuclide tracer through the cannula and then I had to remain in the hot room for 1 hour to let the tracer circulate. After 1 hour, I was taken to the PET scanner and it took around 30-35 minutes. Following that I was allowed to leave for home. It was an extremely easy experience and a significant improvement on doing the 3 day Octreotide scan.
I recently wrote a blog called Neuroendocrine Cancer – Exciting Times Ahead! I wrote that on a day I was feeling particularly positive and at the time, I wanted to share that positivity with you. I genuinely believe there’s a lot of great things happening. Don’t get me wrong, there’s a lot still to be done, particularly in the area of diagnosis and quality of life after being diagnosed. However, this is a really great message from a well-known NET expert.
In an interview with OncLive, Jonathan R. Strosberg, MD, associate professor at the H. Lee Moffitt Cancer Center in Florida, discussed his presentation on NETs at a recent 2016 Symposium, and shed light on the progress that has been made in this treatment landscape.
OncLive: Please highlight some of the main points from your presentation.
Strosberg: The question I was asked to address is whether we’re making progress in the management of NETs, and I think the answer is unequivocally yes. Prior to 2009, there were no positive published phase III trials.
Since then, there have been 8 trials, 7 of which have reached their primary endpoints. So it’s been a decade of significant improvement. And even though none of these studies were powered to look at overall survival as an endpoint, we’re certainly seeing evidence of improvement in outcomes.
OncLive: What are some of the pivotal agents that you feel have impacted the paradigm in the past several years?
Strosberg: The first group is the somatostatin analogs. We use them to control hormonal symptoms like carcinoid syndrome, but with the CLARINET study, we now know that they substantially inhibit tumor growth.
The next significant drug we use in this disease is everolimus (Afinitor), an oral mTOR inhibitor, which is now approved in several indications based on positive phase III studies. The first was in pancreatic NETs and subsequently, based on the RADIANT-4 trial, it was also approved in lung and gastrointestinal NETs. So that was an important advance.
The next important category of treatment is radiolabeled somatostatin analogs, otherwise known as peptide receptor radiotherapy. The one that’s been tested in a phase III trial is lutetium dotatate, also known as Lutathera. It was tested in patients with progressive midgut NETs and showed a very substantial 79% improvement in progression-free survival, and a very strong trend toward improvement in overall survival, which we hope will be confirmed upon final analysis.
OncLive: Are we getting better at diagnosing and managing the treatment of NETs?
Strosberg: Certainly. I think pathologists are better at making the diagnosis of a NET, rather than just calling a cancer pancreatic cancer or colorectal cancer. They’re recognizing the neuroendocrine aspects of the disease, and doing the appropriate immunohistochemical staining.
We also have better diagnostic tools. We used to rely primarily on octreoscan, and in many cases we still do, but there is a new diagnostic scan called Gallium-68 dotatate scan, also known as Netspot, which has substantially improved sensitivity and specificity. It’s not yet widely available, but it is FDA approved and hopefully will enable better diagnosis as well as staging in the coming years.
And, with the increase in number of phase III studies, we’re developing evidence-based guidelines, which will hopefully lead to more standardization, although knowing how to sequence these new drugs is still quite challenging.
OncLive: With sequencing, what are the main questions that we’re still trying to answer?
Strosberg: If we take, for example, NETs of the midgut, beyond first-line somatostatin analogs, physicians and patients often face decisions regarding where to proceed next, and for some patients with liver-dominant disease, liver-directed therapies are still an option.
For others, everolimus is a systemic option, and then hopefully lutetium dotatate will be an option based on approval of the drug, which is currently pending. Knowing how to choose among those 3 options is going to be a challenge, and I think there will be debates. Hopefully, clinical trials that compare one agent to another can help doctors make that choice. It’s even more complicated for pancreatic NETs. Beyond somatostatin analogs, we have about 5 choices—we have everolimus, sunitinib (Sutent), cytotoxic chemotherapy, liver-directed therapy, and peptide receptor radiotherapy. It’s even more challenging in that area.
OncLive: Are there any other ongoing clinical trials with some of these agents that you’re particularly excited about?
Strosberg: There’s a trial that is slated to take place in Europe which will compare lutetium dotatate with everolimus in advanced pancreatic NETs, and I think that’s going to be a very important trial that will help us get some information on both sequencing of these drugs, as well as the efficacy of Lutathera in the pancreatic NET population, based on well-run prospective clinical trials. I’m particularly looking forward to that trial.
OncLive: Looking to the future, what are some of the immediate challenges you hope to tackle with NETs?
Strosberg: One area of particular need is poorly differentiated neuroendocrine carcinomas. That’s a field that’s traditionally been understudied. There have been very few prospective clinical trials looking at this particular population, and we’re hoping that will change in the near future. There are a number of trials taking place looking at immunotherapy drugs. If these agents work anywhere in the neuroendocrine sphere, they are more likely to work in poorly differentiated or high-grade tumors, in my opinion, given the mutational profile of these cancers. So that’s something I’m particularly looking forward to being able to offer these patients something other than the cisplatin/etoposide combination that goes back decades, and is of short-lasting duration.
See more at: http://www.onclive.com/publications/oncology-live/2016/vol-17-no-24/expert-discusses-recent-progress-in-net-management#sthash.ypkilX2A.dpuf
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In the last 12-24 months, there seems to have been announcement after announcement of new and/or upgraded/enhanced diagnostics and treatment types for Neuroendocrine Cancer. Scans, radionuclide therapies, combination therapies, somatostatin analogues, biological therapies, etc. Some of the announcements are just expansions of existing therapies having been approved in new (but significant) regions. Compared to some other cancers, even those which hit the headlines often, we appear to be doing not too badly. However, the pressure needs to stay on, all patients need access to the best diagnostics and treatments for them; and at the requisite time.There’s even more in the pipeline and I’m hoping to continue to bring you news of new stuff as I have been doing for the last year.
Some of these new diagnostics and treatments will benefit eligible patients who are in diagnosis/newly diagnosed and also those living with the disease. As we’re now in our awareness month, let’s recap:
Many NET Patients will undergo a nuclear scan to confirm CT results and/or to detect further neuroendocrine activity. Basically, a nuclear substance is mixed with a somatostatin analogue, injected into the patient who is then scanned using a 360-degree gamma camera. As gamma cameras are designed to show up radioactive activity; and as Neuroendocrine Tumour cells will bind to the somatostatin analogue, it follows that the pictures provided will show where Neuroendocrine tumours are located. Many people will have had an ‘Octreotide’ Scan (or more formally – Somatostatin Receptor Scintigraphy) which is still the gold standard in many areas. The latest generation of nuclear scans is based on the platform of the Gallium (Ga) 68 PET Scan. The principles of how the scan works is essentially as described above except that the more efficient radioactive/peptide mix and better scan definition, means a much better picture providing more detail (see example below). It’s important to note that positive somatostatin receptors are necessary for both scans to be effective. Europe and a few other areas have been using the Ga-68 PET scans for some time (although they are still limited in availability by sparse deployment). The latest excitement surrounding this new scan is because they are currently being rolled out in USA. Read about the US FDA approval here. You may hear this scan being labelled as ‘NETSPOT’ in USA but this is technically the name for the preparation radiopharmaceutical kit for the scan which includes a single-dose injection of the organic peptide and the radionuclide material. Take a look at a comparison of both scans here:
This slide from a recent NET Research Foundation conference confirms the power of more detailed scanning.
Peptide Receptor Radionuclide Therapy (PRRT)
Similar to above, this treatment has been in use in Europe and other places for some time but is also to be formally deployed in USA if, as is expected, the US FDA approval is positive at the end of this year (Read here). In the most basic terms, this is a treatment whereby a peptide is mixed with a radionuclide and is drip fed over a number of treatments (normally up to 4 spaced out over a year). The concept of delivery of the ‘payload’ to the tumours is actually very similar to the preparation for a radionuclide scan as described above, the key difference is the dosage and length of exposure whilst the tumours are attacked. Once again, receptors are important. The NETTER series of trials showed good results and this is an excellent addition to the portfolio for those patients who are eligible for this treatment. Fingers crossed for the US FDA announcement due by the end of this year. Also fingers crossed that PRRT returns to the NHS England & Wales portfolio of available treatments next year. The Carcinoid Cancer Foundation has an excellent summary of PRRT here.
PRRT and Chemo Combo
Whilst on this subject, I also want to highlight the innovative use of combo therapies in Australia where they are combining PRRT and Chemo (PRCRT). I blogged about this here:
Somatostatin Analogues and their Delivery Systems
Somatostatin analogues are a mainstay treatment for many NET Patients. These drugs target NET cell receptors which has the effect of inhibiting release of certain hormones which are responsible for some of the ‘syndromic’ effects of the disease. Again, receptors are important for the efficacy of this treatment. You can read the ‘geeky’ stuff on how they work here. These drugs mainly comprise Octreotide (provided by Novartis) and Lanreotide (provided by Ipsen). The latter has been around in Europe for 10 years and was introduced to North America earlier this year. Octreotide has been around for much longer, almost 17 years. When you consider these peptides have also been used to support nuclear scans that can detect the presence of tumours; and that studies have shown they also have an anti-tumour effect, they really are an important treatment for many NET Patients. I’ve blogged about new somatostatin analogues in the pipeline and you can read this here. This blog also contains information about new delivery systems including the use of oral capsules and nasal sprays (…….. very early days though).
Treatment for Carcinoid Syndrome
For maintenance and quality of life, the release of a Telotristat Ethyl for Carcinoid Syndrome is an exciting development as is the first new treatment for Carcinoid Syndrome in 17 years. This is a drug which is taken orally and inhibits the secretion of serotonin which causes some of the symptoms of the syndrome including diarrhea. It must be emphasised it’s only for treating diarrhea caused by syndrome and might not be effective for diarrhea caused by other factors including surgery. Read about how it works and its target patient group in my blog here.
The announcement of a clinical trial for the Oncolytic Virus (an Immunotherapy treatment)specifically for Neuroendocrine Tumours is also very exciting and offers a lot of hope. Click the photo for the last progress update.
Earlier this year, AFINITOR became the first treatment approved for progressive, non-functional NETs of lung origin, and one of very few options available for progressive, non-functional GI NET, representing a shift in the treatment paradigm for these cancers. It’s been around for some time in trials (the RADIANT series) and is also used to treat breast and kidney cancer. It’s manufactured by Novartis (of Octreotide fame). It has some varying side effects but these appear to be tolerable for most and as with any cancer drug, they need to weighed against the benefits they bring.
In technical terms, AFINITOR is a type of drug known as an ‘mTOR’ inhibitor (it’s not a chemo as frequently stated on NET patient forums). Taken in tablet form, it works by blocking the mTOR protein. In doing so, AFINITOR helps to slow blood vessels from feeding oxygen and nutrients to the tumour.
Check out Novartis Afinitor website for more detailed information. There’s an excellent update about AFINITOR rom NET expert Dr James Yao here. The US FDA approval can be found here.
………. and relax! Wow, I’ve surprised myself by collating and revising the last 12-24 months. Dr James Yao also agrees – check out his upbeat message in the attached2 page summary. You may also like another upbeat message from Dr Jonathan Strosberg by clicking here.
Neuroendocrine Cancer – who’d have thought it? ….. a bit of a dark horse.
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Don’t understand Somatostatin Receptors? Join the club! I got my head around the term ‘Somatostatin’ and ‘Somatostatin Analogues’ some time ago but the term ‘Somatostatin Receptor’ (SSTR) is still a bit of a mystery and it’s come to the top of my list of things to study. SSTRs do come up in conversation quite often and I’m fed up of nodding sagely hoping it will eventually become clear! On analysis it looks like a technical subject – and therefore a challenge 🙂
I’ve taken a logical approach working from ‘Somatostatin’ to ‘Somatostatin Analogue’ before commencing on the ‘receptor’ bit. It is intentionally brief and (hopefully) simplistic!
It’s important to understand this hormone and then why your ‘butt dart’ is generically called a ‘Somatostatin Analogue’.
Some Neuroendocrine Tumours secrete hormones and peptides that cause distinct clinical syndromes, including amongst others, carcinoid syndrome. Somatostatin is a naturally occurring hormone and a known inhibitor of some of these NET related hormones and peptides that can be over secreted and cause syndromes. For example, somatostatin from the hypothalamus inhibits the pituitary gland’s secretion of growth hormone (GH) and Thyroid Stimulating Hormone (TSH). In addition, somatostatin is produced in the pancreas and inhibits the secretion of other pancreatic hormones such as insulin and glucagon. However, the naturally produced Somatostatin does not have the lifespan to have any effect on Neuroendocrine Tumours which are over secreting these hormones and peptides. ……. cue manufactured versions that can!
Somatostatin Analogue (SSA)
These are manufactured versions of Somatostatin known as Somatostatin Analogues. These are designed to have a lasting effect to inhibit for much longer and therefore reduce the symptoms caused by the over secretion (i.e. the syndrome). Examples of Somatostatin Analogue include Octreotide (Sandostatin), Lanreotide (Somatuline) and Pasireotide (Signifor).
So how do Somatostatin Analogues actually work?
For the inhibition to work effectively, there needs to be a route into the over secreting tumours, normally via short or long acting injections or even intravenously. On the tumour cells, there are currently 5 known sub-types of ‘Somatostatin Receptors’ (SSTR) which are ‘expressed’ by most NETs. These are known as SSTR1 through to SSTR5. The naturally occurring hormone Somatostatin attempts to bind with all 5 but as above, it lacks the lifespan to make any impact to inhibit sufficiently in cases of overecretion. However, SSAs can overcome this with the longer lifespan. They can successfully in most cases bind with these receptors to inhibit the hormones and peptides causing the problems, particularly SSTR2 with modest affinity to SSTR5. Clearly it’s therefore advantageous to target SSTR2.
The subtypes expressed by NETs are variable and the efficiency of different SSAs in binding to each SSTR subtype also varies. For example the table below lists the variability of Somatostatin Receptor efficiency in different types of NET. Interesting to note that non-functional NETs might not have efficient SSTRs but SSAs will still try to bind to them albeit it might not work or have a lesser effect.
Somatostatin receptors are found in high numbers on the surface of NET’s. Most receptors are in the inactive state (based on something called the phosphorylation status). Traditionally, agents such as dotatate have only bound to activated receptors on the surface. Scientists are looking at ways to bind to inactive receptors to increase therapy success (for example see clinical trial OPS 201)
Table 1 – Somatostatin receptor subtypes in neuroendocrine tumours (mRNA) (See Copyright)
This table above clearly shows the variability of SSTRs when binding with different types of NETs. It follows that manufacturers of SSAs will be using this data in the formulation of their drugs. If you now look at the table below, you can see how efficiently the 3 well-known SSAs inhibit NETs on each SSTR.
Table 2 – Somatostatin receptor subtype-binding affinity of somatostatin analogues (See Copyright)
You can see from the data why Octreotide and Lanreotide target SSTR2 and to a lesser extent SSTR5 but Pasireotide (Signifor or SOM-230) is interesting as it appears to have affinity for SSTRs 1-3 and 5, probably why it has been approved for Cushing’s Disease (ATCH producing). However, to date, there has not been enough evidence showing that Pasireotide has a progression-free survival benefit over the other 2 therapies. It is also associated with hyperglycemia. You may find this video interesting as the doctor is suggesting it could be used by NET patients in certain scenarios.
What about SSA labelled diagnostics?
The same principles apply. For example, an Octreotide Scan (actually known as ‘Somatostatin Receptor’ Scintigraphy (SRS)) works by taking pictures using a gamma camera which is designed to see radiation from a ‘tracer’. The tracer in question is a radio labelled with an Octreotide variant (such as pentetreotide) which will bind to somatostatin receptors on the surface of the tumour cells In the simplest of terms, this shows up where NETs are. The same principles apply to Ga 68 PET scans which are more advanced and more sensitive than SRS.
What about SSA labelled therapies?
With (say) Peptide Receptor Radiotherapy (PRRT), there is a similar binding mechanism going on. In PRRT, Octreotide or a variant, is combined with a therapeutic dose of the radionuclides, e.g. Yttrium 90 (Y-90) and Lutetium 177 (Lu-177). It binds with the SSTRs on the tumour cells and the therapeutic dose attacks the tumour having been brought there by the binding effect. Simple isn’t it?
Do Somatostatin Receptors work for everyone?
Unfortunately not. Some people have more sensitive receptors than others and the figure of 80% appears to be the most common statistic indicating one-fifth of all NET patients may not be able to respond correctly to SSA treatment or get the right results from Octreoscans/Ga 68 PET and/or PRRT. However, that needs to be taken into context and probably applies to midgut NETs measured against SSTR2 – the tables above tend to confirm this figure. During my research, I did read that higher than normal doses of SSAs may have some effect on those with less sensitive SSTRs. Also, SSAs seem to work much better with well-differentiatedtumours.
How do I know if my Somatostatin Receptors work?
When I was completing my NET checks after diagnosis, my Oncologist declared I was “Octreotide avid” shortly after my Octreoscan was compared with my CT. I’m guessing that is a simple and crude test and how most people find out they have working receptors. I also suspect that if your syndrome symptoms are abated somewhat by SSA injections, then you there is a good chance your SSTRs are working normally. I also suspect those who show clear signs of tumour on CT but not on Octreoscan or Ga 68 PET, could have a receptor issue.
The advent of modern PET scanning (e.g. Ga68) has meant more accurate methods of working out if someone has the right receptors for PRRT through analysis of something known as standardized uptake values (SUV).
A more modern approach is to use a ‘Theranostic Pair” where the same radiolabelled tracer is used with the advantage that the diagnostic element can predict suitability for the therapy component – read more here
Somatostatin Receptor Research – Interest Point
I was please to see a piece of research ongoing to look at the issues with lack of somatostatin receptors. The research is looking at novel imaging agents for NETs which do not have working receptors. Read more here.
I hope this gives you a very basic outline of why Somatostatin Receptors are important to support the diagnosis and treatment of NETs.
Preclinical and clinical studies have indicated that somatostatin receptor (SSTR)expressing tumors demonstrate higher uptake of radiolabeled SSTR antagonists than of the currently approved SSTR agonist versions. See clinical trial OPS 201 for an example of the next generation of somatostatin receptor based theranostics where the use of a somatostatin antagonists.
It’s that time again, every 6 months I need some checks. I’ve done the specialist blood test (Chromogranin A – CgA) and the 24 hour urine (5HIAA) and am waiting on my CT scan appointment. It’s also time for my annual Echocardiogram. I then see my Consultant and he delivers the news. Happy days 🙂
I positively look forward to my tests and I cannot wait to get into that scanner! ‘Scanxiety’ isn’t in my dictionary. Why? Because testing is one thing that’s going to keep me alive for as long as possible. If I don’t get regularly tested, then one day I might just ‘keel over’ because something wasn’t spotted early enough. Even in the event of ‘not so good news’, I still see that as a positive because it means the testing is working and an investigation or further testing can be put into place to find the problem – and the sooner the better. Where’s that scanner, get me in it!
One of the most common posts on NET Cancer forum sites is to express personal concerns or worries about upcoming appointments or waiting on the test results. Thinking back to my own countless appointments either for testing, treatment or for receiving results, I appear to be consistently pragmatic in my approach.
The test results will be what the test results will be. Worrying about them is not going to change them!
Bring it on!
You may enjoy my article “Living with Neuroendocrine Cancer – 7 tips for conquering fear”. Read here
I thought long and hard about today’s post because no matter what I say, it will pale into insignificance when put alongside the words of Stephen Sutton who sadly died today at the tender age of 19. The words used by his mother are particularly powerful. He was certainly a courageous, selfless and inspiring man.
However, although he successfully raised £3.2million for Teenage Cancer Trust – a phenomenal amount for a very worthy charity, I believe Stephen also leaves behind many other very valuable legacies and lessons. I’d like to focus on two in particular.
This is one of the key technical innovations of the last 20 years and has changed the way in which society lives and communicates and it’s still evolving. It has altered the way ideas change hands and how fast those ideas spread – seconds rather than days or weeks. It’s a very powerful tool which can send messages to those who lead and govern us. In my opinion, this has actually been good for democracy (people power) – which is why certain countries (no names no pack drill) fear the rise of social media because it removes their ability to control information and views.
However, it can also be abused by those who take advantage of these freedoms for their own selfish, uncaring and nasty minded purposes. Stephen was abused ‘electronically’ when he entered a short period of better health and certain people with very narrow minds decided to cowardly suggest (without checking the facts) that they had been duped.
When I published my ‘A’ letter blog, Chris reminded me that I had originally listed ‘Awareness’ as a candidate for blogging – after all, this is one of the two aims of our sponsored activity. I knew there would be an opportunity downstream and having just read Stephen’s whole story, I decided to raise it today.
Stephen was diagnosed with metastatic bowel cancer at the age of 15. He had been suffering sickness, stomach pains, weight loss and a loss of appetite but was repeatedly told by doctors he had constipation. Tragically, it was six months before Stephen’s cancer was finally discovered. It was only picked up after an emergency CT scan when he became so ill he couldn’t keep down any food or fluids and he couldn’t sleep because of the pain. He believed that if he had been diagnosed sooner, his prognosis might have been very different although he went on to say ‘But even saying that, I’m not one to dwell on the past. It is what it is.’ I’m in no way having a ‘pop’ at Stephen’s doctors as I think there is a lot of detail behind the scenes and nobody knows the full facts. I actually think medical staff are on a ‘hiding to nothing’ nowadays.
Awareness is also germane to Neuroendocrine Cancer which is infamous for being misdiagnosed due to the vagueness of some of the symptoms it can cause and produce. The Neuroendocrine Cancer community has a motto “If you don’t suspect it, you can’t detect it“. So my message to you is this – if you feel unwell, make sure you divulge all the facts to your GP or attending physician. If you end up being diagnosed with something minor but you still feel there might be something seriously wrong, go back and then go back again – or ask for a second opinion.
I leave you with a listing of a couple of ‘O’ words which are significant for Neuroendocrine Cancer.
One of the major advances in the treatment of Neuroendocrine Cancer in the past 10 years is the introduction of ‘Somatostatin Analogues’. These are synthetic (man-made) drugs which mimic the behaviour of somatostatin, a naturally occurring inhibitory hormone which blocks the release of several other hormones, which in excess, can cause unwanted side effects and in particular scenarios, can potentially be damaging and life threatening. I’m actually treated by a variant of this drug called Lanreotide. I’ve referred to this on a number of occasions – see:
‘Does my flush beat yours‘ http://wp.me/p4AplF-2w
‘My treatment is a pain in the butt‘ http://wp.me/p4AplF-6c
The long acting versions of this type of drug (normally 4 week intervals) now have an established place in the medical treatment of patients with neuroendocrine tumours. These drugs have made a significant difference to the outcomes for Neuroendocrine Cancer patients in terms of quality and extent of life. There is some build up of evidence to suggest these drugs also have an ‘anti-tumour’ effect (i.e. they stunt or reverse tumour growth) but I do not believe there are any widely recognised scientific claims yet published.
This is a gamma camera type scan where Octreotide is mixed (radio labelled) with a very low dose radioactive material (normally Indium-111). Somatostatin analogues will ‘bind’ to neuroendocrine tumours releasing excess hormones. If you then combine the drug with radioactivity and take a picture using a gamma camera, this can detect functioning tumours that might not otherwise be spotted. Seemples! This is actually how they found the tumours in my left armpit (axillary lymph nodes) and left collar-bone (supraclavicular fossa lymph nodes).
They inject the drug/radioactive mix on the morning of day 1 and then they scan you each day for 3 days (day 1, 2 and 3). The bench you lie face up on is quite narrow and you need to remain still. The gamma camera rotates around your body in a circle moving up or down after each trip. The radiographers will also try to overlay the scan output onto CT scan pictures to compare and cross reference potential tumour sites. For the patient, it’s the most boring scan ever……but very clever and very important.
Sorry it’s a bit lengthy today. However, if you like it, please feel free to share. As usual comments also welcome.
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There’s a few ‘G’ items to talk about so here goes……
There wasn’t really anything wrong with my gallbladder but it had to go. You may have read previously that I receive a monthly injection of a ‘snazzy’ drug which keeps me well. However, long term use of this drug has certain side effects, one being the risk of gallstone formation in up to 50% of cases. Gallstones can not only be very painful but they can potentially be life threatening. On top of what I had already endured, future surgery to treat gallstones or to remove my gallbladder could be riskier than it might normally have been, so it was conveniently removed during a second major operation on my liver (the gallbladder is located very close).
The gallbladder plays an important role in the digestion of food by storing bile produced in the liver until it is needed for digesting fatty foods in the duodenum (the first part of the small intestine). Bile now flows down the bile ducts from my liver into my duodenum. Clearly this isn’t as efficient as using the gallbladder with ‘on-demand’ bile and so produces its own side effects. In my own experience, this can be offset to a certain degree by making minor adjustments to diet.
Gallium PET Scans
One of the difficulties with Neuroendocrine Cancer is actually pinning down the precise location of the tumours as they can be small, they can hide in awkward places and sometimes they can be difficult to display correctly on conventional scanners. Previously the gold standard of scan for Neuroendocrine patients is the ‘Octreotide’ Scan which can ‘light up’ neuroendocrine tumours on a gamma camera. However, the Gallium PET scan, which works in a similar way, is even more sensitive and its better results can affect a doctor’s decisions on how to treat patients. Despite this, there is only one hospital in the UK (in London) which has the license to use it. Please sign this e-petition and share widely to address this lack of access to a potentially life saving diagnostic tool. http://epetitions.direct.gov.uk/petitions/56106
There are few events I would describe as a milestone in my lifetime. Without doubt one for me is becoming a grandfather! I’m now a very proud and doting grandfather to 4 boys – Ben (10), Sam (8), Thomas (5) and Charlie (1¾). When I see them, the feeling of pride, emotion and love is like the first time, it never seems to subside. I intend seeing them grow up, finish eduction, get jobs, get married and have their own kids ♥
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