Neuroendocrine Tumor Drug Clinical Trial – Cabozantinib (includes news on Pheochromoctyoma and Paraganglioma)

What is Cabozantinib?

Cabozantinib is an oral drug which works by blocking the growth of new blood vessels that feed a tumour. In addition to blocking the formation of new blood cells in tumours, Cabozantinib also blocks pathways that may be responsible for allowing cancers cells to become resistant to other “anti-angiogenic” drugs. It is a type of drug called a growth blocker.  Cabozantinib has been studied or is already in research studies as a possible treatment for various types of cancer, including prostate cancer, ovarian cancer, brain cancer, thyroid cancer, lung cancer, and kidney cancer. During my research, I found that it has a connection to Medullary Thyroid Cancer (MTC) which is a type of Neuroendocrine Cancer, frequently associated with Multiple Endocrine Neoplasia (MEN).  Cabozantinib, under the brand name of ‘Cometriq’ was approved by the FDA in 2012 for use in MTC.  Read more about Cometriq here.  It’s also been approved by the FDA for advanced renal cell carcinoma (RCC) (branded as Cabometyx). I also discovered that there is an exclusive licensing Agreement with the manufacturers (Elelixis) and Ipsen (of Lanreotide fame) to commercialize and develop Cabozantinib in regions outside the United States, Canada and Japan

Growth blockers are a type of biological therapy and include tyrosine kinase inhibitors, proteasome inhibitors, mTOR inhibitors, PI3K inhibitors, histone deacetylase inhibitors and hedgehog pathway blockers.  Cabozantinib is a tyrosine kinase inhibitor (TKI).  They block chemical messengers (enzymes) called tyrosine kinases.  Tyrosine kinases help to send growth signals in cells so blocking them stop the cell growing and dividing.  Some TKIs can block more than one tyrosine kinase and these are known as multi-TKIs.

cabozantinib-picture
Example action of Cabozantinib

So Capozantinib is a tyrosine kinase inhibitor and is therefore a biological therapy and growth blocker just like Everolimus (Afinitor) and Sunitinib (Sutent) – some texts describe thelattero two as chemotherapy but this is just not accurate.

Very technical process but in the simplest of terms, Cabozantinib is designed to disrupt the actions of VEGF (a growth factor) and MET (a growth factor receptor) which promote spread of cancerous cells through the growth of new blood vessels.  Whilst we are on this subject, please note Everolimus (Afinitor) is an mTOR inhibitor and Sunitinib (Sutent) is a tyrosine kinase inhibitor. Many people think these drugs are a type of chemo – that is incorrect, these are targeted biological therapies.  See more on this by clicking here.

What is the current trial status of Capozantinib?

A Phase III trial is now recruiting entitled Cabozantinib S-malate in Treating Patients With Neuroendocrine Tumors Previously Treated With Everolimus That Are Locally Advanced, Metastatic, or Cannot Be Removed by Surgery”. 

The trial has 172 locations across the US (see link below). The primary study (final data) is scheduled Jan 1st 2021.

You can read the trial documentation by clicking here.

Progress report

  1. Poster submission for 2017 Gastrointestinal Cancer Symposium
  2. Onc Live output from the 2017 Gastrointestinal Cancer Symposium
  3. Output from NANETS 2017
  4. A funded piece of research by the NET Research Foundation – check it out herelooks like they are trying to figure out what patients might benefit from Cabozantinib using biomarker data to predict response.
  5. Dr Jennifer Chan speaking in 2018 about the drug potential.  (Apologies for the use of the out of date term ‘Carcinoid‘).
  6. Phase 3 Clinical Trial Document – click here

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UPDATED 2018 – There’s also another trial looking at unresectable metastatic Pheochromocytomas and Paragangliomas

A Phase 2 Study to Evaluate the Effects of Cabozantinib in Patients with Unresectable Metastatic Pheochromocytomas and Paragangliomas 

This part is from an article collaboration between MedPage Today® and the American Association of Clinical Endocrinologists

BOSTON — Cabozantinib (Cabometyx) may benefit patients with malignant pheochromocytomas and paragangliomas, according to results of a phase II trial presented here.

Patients receiving cabozantinib (Cometriq) treatment experienced notable tumor shrinkage in the lymph nodes, liver, and lung metastases, according to Camilo Jimenez, MD, of the MD Anderson Cancer Center in Houston, and colleagues.

Additionally, progression-free survival significantly increased after treated to 12.1 months (range 0.9-28) compared with just 3.2 months prior to treatment, they reported at the American Association of Clinical Endocrinologists (AACE) annual meeting.

Cabozantinib treatment was also tied to an improvement in blood pressure and performance status, as well as remission of diabetes among these patients.

“Malignant pheochromocytomas and paragangliomas are frequently characterized by an excessive secretion of catecholamines. [Patients] have a large tumor burden and they have a decreased overall survival,” explained Jimenez. “Tumors are frequently very vascular and frequently associated with bone metastases. In fact, up to 20% of patients who have malignancy of pheochromocytomas and paragangliomas may have predominant bone metastases.”

He added that “an interesting aspect of this tumor is that C-MET receptor mutation have been found in occasional patients with malignant pheochromocytomas and paragangliomas.”

Cabozantinib is an anti-angiogenic tyrosine kinase inhibitor, which also targets RET, MET, and AXL. It is approved for metastatic medullary thyroid cancer, and was more recently approved for first-line treatment of advanced renal cell carcinoma.

“MET pathway is also involved in the development of bone metastases. In fact, cabozantinib is a very effective medications for patients who have bone metastases in the context of cancer of different origins,” Jimenez said.

In order to be eligible for the trial, patients with confirmed pheochromocytoma or paraganglioma had to be ineligible for curative surgery, have ≥3 months life expectancy, no risk for perforation or fistula, and adequate organ functioning. Prior to cabozantinib initiation, patients could not receive chemotherapy or biologic agents within 6 weeks, radiation within 4 weeks, or MIBG within 6 months.

Following histological confirmation of disease progression >1 year according to RECIST 1.1, the trial included 14 patients with measurable disease and eight patients with predominant/exclusive bone metastases. Fifteen patients subsequently enrolled into the trial, six of whom had germline mutations of the SDHB gene.

All participants were all started at an initial daily dose of 60 mg of cabozantinib, which was subsequently reduced down to between 40 to 20 mg due to toxicity in 13 patients based on tolerance.

The majority of these patients with measurable disease experienced some level of disease response. Six patients reported a partial response, defined as over a 30% reduction, while three patients achieved moderate response, marked by a 15%-30% reduction. Five of the patients with predominant bone metastases reported disease stabilization, according to results of an FDG-PET scan. One patient experienced disease progression while on treatment.

Overall, cabozantinib was generally well-tolerated without any grade 4 or 5 treatment-related adverse events reported. Some of the most common adverse events reported included grade mild dysgeusia, hand and foot syndrome, mucositis, fatigue, weight loss, and hypertension, according to the authors.

  • Primary Source – American Association of Clinical Endocrinologists meeting – AACE 2018; Abstract 142. attended my Medscape writers

You can see the Pheo/Para clinical trial document by clicking here.

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Summary

I generated this blog article to add value rather than just post the outputs for your own perusal.  I hope you find it useful.

Please note that taking part in a clinical trial is a big decision and must be considered carefully in conjunction with your specialists if necessary.  This article is not suggesting this trial is right for you.  Please check the inclusion and exclusion criteria in the trials document carefully. (Pheo/Para patients see other clinical trial link above)

Chemo or not Chemo – that is the question 


I’m continually seeing certain drugs for treatment of Neuroendocrine Tumours (NETs) described as chemotherapy. I think there must be some confusion with more modern drugs which are more targeted and work in a different way to Chemotherapy.

I researched several sites and they all tend to provide a summary of chemotherapy which is worded like this:  Chemotherapy means:

a treatment of cancer by using anti-cancer medicines called cytotoxic drugs.  Cytotoxic medicines are poisonous (toxic) to cancer cells. They kill cancer cells or stop them from multiplying. Different cytotoxic medicines do this in different ways. However, they all tend to work by interfering with some aspect of how the cells divide and multiply. Two or more cytotoxic medicines are often used in a course of chemotherapy, each with a different way of working. This may give a better chance of success than using only one. There are many different cytotoxic medicines used in the treatment of cancer. In each case the one (or ones) chosen will depend on the type and stage of your cancer. Interestingly, there are several statements along the lines of ‘Cytotoxic medicines work best in cancers where the cancer cells are rapidly dividing and multiplying’, a key issue with lower grade NETs.

Well known chemotherapy treatments for NETs include (but are not limited to): Capecitabine (Xeloda), Temozolomide (Temodal), Fluorouracil (5-FU), Oxaliplatin (Eloxatin) Cisplatin, Etoposide (Etopophos, Vepesid), Carboplatin, Streptozotocin (Zanosar). Some of these may be given as a combination treatment, e.g. CAPecitabine and TEMozolomide (CAPTEM).

In the past, any medication used to treat cancer was regarded as chemotherapy. However, over the last 20 years, new types of medication that work in a different way to chemotherapy have been introduced. Many of these new types of medication are known as targeted therapies. This is because they’re designed to target and disrupt one or more of the biological processes that cancerous cells use to grow and reproduce.  They are classed as biological therapy.  In contrast, chemotherapy medications are mostly systemic in nature and designed to have a poisonous effect on cancerous cells, thus the term ‘cytotoxic’.

The following well known NETs treatment are not really chemotherapy and describing them in this way is not only misleading but may actually cause alarm to other patients. Furthermore, if you check any authoritative NET Cancer specialist or advocate organisation; any general and authoritative cancer site or the manufacturer’s websites; you will not see the drugs below listed within the term chemotherapy.

Somatostatin Analogues e.g. Sandostatin (Octreotide), Somatuline (Lanreotide).  Although these drugs have an anti-cancer effect for some, they are in fact hormone inhibitors and are therefore a hormone therapy.

Everolimus (Afinitor).  This is a targeted biological therapy or more accurate a mammalian target of rapamycin (mTOR) inhibitor. It is a type of treatment called a signal transduction inhibitor. Signal transduction inhibitors stop some of the signals within cells that make them grow and divide. Everolimus stops a particular protein called mTOR from working properly. mTOR controls other proteins that trigger cancer cells to grow. So everolimus helps to stop the cancer growing or may slow it down.

Sunitinib (Sutent).  This is a targeted biological therapy or more accurate a protein (or tyrosine) kinase inhibitor. Protein kinase is a type of chemical messenger (an enzyme) that plays a part in the growth of cancer cells. Sunitinib blocks the protein kinase to stop the cancer growing. It can stop the growth of a tumour or shrink it down.

I can only speculate why some of the confusion exists but I do have some personal experience I can quote too. Firstly I believe it could be easier for some people to describe the new agents as ‘chemotherapy’ rather than explain things such as somatostatin analogues, ‘mammalian target of rapamycin (mTOR) inhibitors’, protein kinase inhibitor or angiogenesis inhibitors. Another reason could be that health insurance companies do not have the correct database structures in place on their IT systems and therefore need to ‘pigeon hole’ drugs into the closest category they can see. Often this is chemotherapy and this only adds to the confusion. In the days when I had health insurance, my Lanreotide injections were coded as chemotherapy on all my bills. I challenged it and this is how they explained the issue.

I’m sure there’s other reasons.

Thanks for reading

Ronny

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Remember ….. in the war on Neuroendocrine Cancer, let’s not forget to win the battle for better quality of life!

Chemotherapy for Neuroendocrine Cancer


Chemotherapy and Neuroendocrine Cancer

One of the unusual aspects of Neuroendocrine Cancer is that chemotherapy is not normally considered as a ‘standard’ treatment unlike many other cancers. One exception is high grade (Grade 3) where it is often a first and/or second line therapy.  Poorly differentiated Neuroendocrine disease is normally labelled as Neuroendocrine Carcinoma (NEC) but worth pointing out there is now a Grade 3 well differentiated classification known as a ‘Grade 3 NET’ rather than Grade 3 NEC. Depending on Ki67 score, there could be differing treatment options for Grade 3 NET and Grade 3 NEC.  Read more in my articles Staging and Grading and High Grade.

Many people think Chemotherapy has a short life span due to recent advances in medical science, some citing Immunotherapy as it’s replacement. However, it’s far too early to write off chemotherapy which is still used in many scenarios and remains a tool in the arsenal of cancer treatments and is predicted to do for some time yet.  See more informed reporting about this below.

Which Chemo for which Neuroendocrine Cancer type and grade/differentiation? 

The type of chemo or the combination of different treatments will often depend on the tumour type and anatomical location involved but may include (but not limited to): Capecitabine (Xeloda), Temozolomide (Temodal), Fluorouracil (5-FU), Oxaliplatin (Eloxatin) Cisplatin, Etoposide (Etopophos, Vepesid), Carboplatin, Streptozotocin (Zanosar). Some of these may be given as a combination treatment, e.g. CAPecitabine and TEMozolomide (CAPTEM). many as a combo treatment.  There is a useful article explaining the role of Ki-67 in determining optimal chemotherapy in high grade neuroendocrine tumors.

Cytotoxic chemotherapy is often inadequate for treatment of Grade 1 and 2 (well differentiated) Neuroendocrine tumours which have a low proliferation index. Chemotherapy does not appear to like their slow cytokinetic growth. However,  it tends to work better on certain parts of the anatomy than others, e.g. pancreatic NETs and Lung NETs.  Of interest is a statistic from NET Research Foundation indicating that 23% of patients who were to be prescribed chemo had their treatment changed to a non-chemo option following a Ga68 PET scan.  Read more here.

For second line therapy (including for well differentiated NETs where other conventional treatments are not working), chemo may be given.  These include (but not limited to) Capecitabine, Temozolomide, Bevacizumab, Xelox, Folfox.  There are other specialist chemos for Mixed Neuroendocrine Non-Neuroendocrine Neoplasms (MiNEN).

‘Horses for Courses’ – Chemo is sometimes used for well differentiated lower grade NETs.

There’s a myth that circulates the NET patient forums along the lines of “chemotherapy does not work for NETs“.  That’s not entirely true but most will not get chemotherapy and this can often lead to confusion in those with Stage 4 cancer when asked by others why they are not receiving chemo.

Capecitabine plus Temozolomide (CAPTEM for short) is fast becoming the standarad chemotherapy treatment when it is required with certain lower grade NETs.  Dr Robert Fine says the results of the CAPTEM trial showed “tremendous responses in every neuroendocrine tumor”. The treatment elicited a response rate of 45% and a stable disease rate of 52% including those with certain types of NETs and pituitary tumours – types of neuroendocrine tumour that are notoriously ‘chemoresistant’.  You can read more about this here (click here) and you can also listen to Dr Fine talking about this on a short You Tube video clip – (click here).  Clearly it’s true that it’s not going to work for all.

Other CAPTEM Resources:

  • There’s a very interesting report on the use of CAPTEM in NETs – (click here)
  • CAPTEM Trial Document – (click here)

PRRT and Chemo Combo Treatment

In Australia, they’re also using a combo treatment of chemo (CAPTEM) and PRRT – I blogged about this click here.

“Chinese Dumplings”

There’s also a useful surgical technique which includes the use of intra-operative chemo, known as “Chinese Dumplings” – I wrote about this click here.

Chemo Embolisation

My Oncologist did mention Chemotherapy on my initial meeting, that was a shock and realisation I had something serious.  However, that never transpired but I was once scheduled to have a chemo-embolisation (or TACE, Trans-arterial Chemo Embolisation). Clearly TACE is more targeted than conventional and generally systemic chemotherapy techniques. Perhaps that my Oncologist actually meant.  The chemo-embolisation never transpired either (long story).

Chemotherapy vs Targeted Biological Agents and Somatostatin Analogues

I often see people describing Somatostatin Analogues (Lanreotide/Octreotide), Afinitor (Everolimus) and Sutent (Sunitinib) as chemo but that’s isn’t technically correct, and I’ve yet to find a NET Specialist or a NET Specialist Organisation who classifies these drugs as chemo.  See my article “Chemo or not Chemo” (click here).

Future of Chemo?

A lot is written about how much longer chemo will be around.  It gets a bad press – I suspect mainly due to the side effects.  There are suggestions that it will eventually be replaced by Immunotherapy and other treatments downstream.  However, immunotherapy is really still in its infancy and there remains a lack of long term data on success rates and side effects.  I suspect chemo will be around for a while longer, particularly for cancers where it has a track record of curing according to ASCO.  Very recently (June 2018), cancer experts said that chemo will be around for a long time yet – read more here

None of the content of this post should be interpreted as advice or a  recommendation for chemotherapy. If in doubt about suitability for any form of chemo, or the type you have been prescribed, patients should seek the advice of their treating doctor or NET specialist.

Thanks for reading

Ronny

I’m also active on Facebook.  Like my page for even more news.  I’m also building up this site here: Ronny Allan

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Remember ….. in the war on Neuroendocrine Cancer, let’s not forget to win the battle for better quality of life!

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