PRRT – The Sequel? – Clinical trial of Targeted Alpha-emitter Therapy (TAT) –  212 Pb-AR-RMX

Radioimmunotherapy

In 2018, RadioMedix Inc. and Areva (parent company Orano Med) initiated the Phase 1 trial for AlphaMedixTM in patients with somatostatin receptor (SSTR) positive Neuroendocrine Tumors (NETs) – an NIH supported trial.

AlphaMedixTM is composed of a somatostatin analogue radiolabeled with 212Pb, an isotope used for Targeted Alpha-emitter Therapy (TAT).  This open-label, dose escalation study’s objective is to determine safety, bio-distribution, and preliminary effectiveness of 212 Pb-AR-RMX in adult patients with differentiated (sic) NETs. “Targeted Alpha-emitter Therapy (TAT) is the wave of the future in nuclear oncology and has a tremendous potential to treat patients with NET and overcome some of the limitations of current Peptide Receptor Radionuclide Therapy (PRRT)” said Dr. Ebrahim S. Delpassand, Chairman and CEO of RadioMedix, sponsor of the trial. They further announced on 21 Feb 2018 that the first patients had undergone some treatment.

The funding for Phase 2 was granted by NIH on 22 Jan 2019.

What is Targeted Alpha-emitter Therapy?  Targeted Alpha Therapy is based on the coupling of alpha particle emitting radioisotopes to tumour selective carrier molecules, such as monoclonal antibodies or peptides. These molecules have the ability to selectively target tumour cells even if they are spread throughout the body. They recognize the targeted cancer cells through antigens that are expressed on the cell surface and can bind selectively to these cells, similar a key fitting into a lock. In targeted alpha therapy these carrier molecules serve as vehicles to transport the radioisotopes to the cancer cells. This is called the “magic bullet” approach. Radioisotopes that emit alpha particles seem particularly promising to selectively destroy cancer cells. Alpha particles have a high energy in the range of 5-9 MeV and at the same time a very short path length in human tissue below 0.1 mm, corresponding to less than 10 cell diameters. Consequently, the use of alpha emitters allows the specific targeting and killing of individual malignant cells, while minimizing the toxicity to surrounding healthy tissue. Extracted from EU Science Hub

According to the clinical trials document, this drug addresses an unmet need in the field of peptide receptor radionuclide therapy (PRRT) for NETs. Substitution of an alpha emitter (²¹²Pb) for the beta emitters currently being used (i.e., 177Lu or 90Y) will provide significantly higher Linear Energy Transfer (LET) and a shorter path length. Higher LET particles should cause more tumor cell death. Shorter path length should result in less collateral damage of the normal tissue and therefore less side effects for subjects receiving the drug.

What is the difference between PRRT and TAT?  From the scant ‘patient understandable‘ information currently available, it would appear that TAT has the potential to be more targeted and less toxic than PRRT – to me that seems like it would be able to target smaller tumors.  I also noted that TAT is sometimes described as a ‘radioimmuotherapy’ or ‘alpha immunotherpy’, indicating the mechanism of action is significantly different to that of conventional PRRT. It was also described as a ‘Trojan Horse’ which would seem to hint at its immunotherapy credentials.

I noted that TAT is also being studied for use in Prostate Cancer and Leukaemia.

Related articles:

Announcement of Phase 1 Clinical Trial – click here – results to follow.

Funding grant from NIH for Phase 2 – click here

Phase 1 Clinical Trial Document Phase 1 Study of AlphaMedix™ in Adult Subjects With SSTR (+) NET – click here – Phase 2 document to follow.

Areva Med Website – click here

RadioMedix Inc Website – click here

You may also enjoy my articles:

Lutetium Lu 177 dotatate (Lutathera®) – PRRT” – click here.
Expanding PRRT – Trial of 177Lu-Edotreotide (Solucin®) – COMPETE Trial” – click here.
Theranostics – a find and destroy mission” – click here
Ga68 PET Scans – into the unknown” – click here

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

Disclaimer

My Diagnosis and Treatment History

Most Popular Posts

Sign up for my twitter newsletter

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

patients included

Please Share this post:

Let’s talk about living with NETs

being_there_front
Graphic courtesy of Ellie McDowell

There’s a frequently asked question on certain forums along the lines of how will I die of my Neuroendocrine Cancer?. Personally, I find it slightly unsettling, although I can understand why certain people might ask. I accept it as a question but I believe there are times and places for it and that a public forum is not the place to have it. The vast majority of people do not go to a forum to find out how they might die.  I can see a list of search terms for hits on my blog site (I don’t know who searched just what was searched). Would you believe this also appears from time to time?  I just hope they found this post!

I don’t tend to dabble in death – it’s just quite difficult to talk about it in a blog which is part designed to be positive and offer hope. So why am I talking about death inside this positive blog? Well, apart from thinking the thread mentioned above might scare readers who are already frightened by their diagnosis, perhaps quite recent, and do not want the answer to this question, I also think it might be perceived as a bit ‘glass half empty’. Both of these things are not good, thus why I believe the question should be between the person wanting to know and a specialist.

I also believe the “how will I die of Neuroendocrine Cancer” question is a really big assumption about the cause of death. Why? There’s an increasing chance a person with cancer today will die of something else. For example, in UK today, more than one in three (35%) of those people who die having had a cancer diagnosis will now die from other causes. This is up from one in five (21%) 20 years ago. By 2020 this will improve further to almost four in 10 people (38%). This means the number of people who get cancer but die from another cause has doubled over the past 20 years. The cancer story is changing and a quick bit of research confirms it’s changing on a worldwide basis.

On a similar subject, for those looking online for NETs prognostic data, I offer the following advice:

  1. Be careful surfing the internet, some sites have NETs prognostic data from the ark.
  2. Even if you find the very latest data, interpretation is difficult due to the heterogeneity of NETs, different stages and grades, comorbidities, age and no doubt many other factors. Please also note the ‘very latest’ data is probably a few years old.
  3. It’s a difficult question even for a specialist.
  4. I’ve lost count of the number of people who have told their story about being told a period of time from their specialist (including use of the word ‘terminal’) and they are still here a significant period after, in some cases 10 x what their specialist said.
  5. AND DEFINITELY Check out the comments on this Facebook post – here (over 400 people like this post so far – so press that button!)
  6. Learn how to conquer your fear – click here

Here’s a much better question people should be asking ……How do I live with NETs?”

Fear won’t stop you dying but it might just stop you living

Thanks for reading

Ronny – diagnosed 2010 and still a newbie

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

Neuroendocrine Cancer – don’t break my heart!

dont break my heart

NEW – 2017 guidance issued.  Diagnosing and Managing Hedinger Syndrome (Carcinoid Heart Disease) in Patients With Neuroendocrine Tumors – An Expert Statement published in the Journal of the American College of Cardiology.

The following are key points to remember from this Expert Statement about the diagnosis and management of carcinoid heart disease in patients with neuroendocrine tumors:

  1. Carcinoid heart disease is a frequent occurrence in patients with carcinoid syndrome and is accountable for substantial morbidity and mortality.
  2. The pathophysiology of carcinoid heart disease is not well understood; however, chronic exposure to excessive circulating serotonin is considered one of the most important contributing factors.
  3. N-terminal pro–B-type natriuretic peptide (NT-proBNP) appears to be the best biomarker to date for screening carcinoid syndrome patients for evidence of clinically significant carcinoid heart disease (Evidence Level 2-3, Grade B).
  4. Measurement of either 24-hour urine 5-hydroxyindoleacetic acid (5-HIAA) or plasma 5-HIAA is mandatory for diagnosis and follow-up of carcinoid syndrome. Furthermore, a 24-hour urinary 5-HIAA level >300 μmol/24 hour is a useful marker for identifying those at risk of developing carcinoid heart disease (Evidence Level 2, Grade B).
  5. Transthoracic echocardiography remains the gold standard for diagnosis and follow-up of carcinoid heart disease. It should be performed in all patients with carcinoid syndrome and high suspicion of carcinoid heart disease, such as clinical features or raised NT-proBNP and/or 5-HIAA levels. For established carcinoid heart disease, echocardiography should be performed if dictated by a change in clinical status; otherwise/thereafter every 3-6 months, depending on the severity of established carcinoid heart disease and clinical status (Evidence Level 2, Grade B).
  6. Cardiac magnetic resonance can be used to evaluate the pulmonary valve, identify cardiac metastases, and assess right ventricular size and function (Evidence Level 2, Grade B).
  7. Long-acting formulations of somatostatin analogs are the standard treatment used to alleviate symptoms related to the carcinoid syndrome, and prevent the development and/or progression of carcinoid heart disease (Evidence Level 2, Grade B).
  8. In cases of carcinoid syndrome that are refractory to somatostatin analogs, options include escalation of the somatostatin analog dose to above labeled doses, addition of IFN-alfa, or peptide receptor radionuclide therapy (PRRT). The oral serotonin synthesis inhibitor, telotristat, represents a promising agent to improve symptoms of the carcinoid syndrome; however, it is not yet approved, and is currently only available for compassionate use in the United States. Given the limited data, everolimus cannot currently be recommended for the treatment of carcinoid syndrome (Evidence Level 2-4, Grade B/C). (NOTE: Since publication, PRRT now widely approved).
  9. The patient with carcinoid heart disease should be managed by a specialized multidisciplinary team, within a setting of a specialized neuroendocrine tumor (NET) center (Evidence Level 5, Grade D).
  10. An experienced medical (cardiologists and NET specialists with involvement of other specialists as necessary), surgical, and anesthetic team approach to the patient with carcinoid heart disease is critical to provide state-of-the-art management for these patients (Evidence Level 5, Grade D).
  11. The choice of valve prosthesis should be individually tailored on the basis of the patient’s bleeding risk, and possible future therapeutic interventions. Biological valve prostheses are the preferred option (Evidence Level 4, Grade D).
  12. To prevent a carcinoid crisis during surgery, the patient should be started on an IV octreotide infusion at a rate of 50-100 mcg/h at least 12 hours preoperatively; this should be continued throughout the procedure and until stable. Patients should be monitored for occurrence of bradycardia if high doses of octreotide are used (Evidence Level 4, Grade C).
  13. Patients with confirmed carcinoid heart disease should be referred to a NET center with cardiology and cardiac surgery departments having expertise in dealing with this complex pathology (Evidence Level 5, Grade D).

chd treatment

A useful abstract of Carcinoid Heart Disease information written by a patient for patients is below.

Neuroendocrine Cancer has certain unique features whereby tumours can produce one or more symptoms which are known collectively as a syndrome.  Neuroendocrine Tumours secreting excess amounts of serotonin, can be accompanied by Carcinoid Syndrome which if not diagnosed and treated early enough, can lead to an additional complication known as Carcinoid Heart Disease (CHD) or Hedlinger Syndrome. However, very late diagnoses can present with CHD already in place.

Excess serotonin, a hormone released by NETs into the bloodstream seems to be the prime and lead suspect for causing thick ‘plaques’ or fibrosis tissue within the heart muscle and damage to (mainly) the tricuspid and pulmonary valves on the right side of the heart which can become ‘tightly narrowed’ or ‘leaky’.  Other substances associated with Carcinoid Syndrome may also be involved (e.g. tackykinins). The presence of liver metastases may allow large quantities of these substances to reach the right side of the heart without being filtered out by the liver but the primary and other secondaries can still contribute to the problem. It’s important to note that the damage is nearly always caused by excess secretions of substances from malignant neuroendocrine cells rather than any direct metastatic involvement of the heart.

Patients with carcinoid heart disease normally present with symptoms such as breathlessness (dyspnea), fatigue, ascites, swollen ankles (edema). However some patients can be asymptomatic.  The left side of the heart is relatively protected, with the pulmonary circulation filtering out the majority of the serotonin and other substances produced by the tumours.  However, involvement of the left-sided valves can sometimes be seen in patients with very active metastatic disease, bronchial carcinoid or those with an existing heart condition known as Patent Foramen Ovale (hole in the heart).

When I was diagnosed in 2010, I was displaying symptoms of carcinoid syndrome and had to undergo a plethora of tests including something called an Echocardiogram – a sonogram (ultrasound) of the heart. Note – it is NOT abbreviated as ECG, which lay persons often use as an abbreviation for an Electrocardiogram – a totally different test.  Carcinoid heart disease is a relatively late manifestation of neuroendocrine tumours; however, it can have an impact on the prognosis of these patients. Thus, early testing is vital for each patient presenting with carcinoid syndrome so that treatment can be considered. Whilst there are certain biomarkers which might indicate the potential for Carcinoid Heart Disease to be present, Echocardiography is the gold standard for detection. Depending on the results of the Echocardiogram, two further investigatory tests may be ordered up – transoesophageal echocardiogram and cardiac catheterisation.  Patients without symptoms can undertake a blood test called NT-proBNP which can function as a screening test.

If you ‘google’ Carcinoid Heart Disease, be careful where you look as there are some statistics to be found in terms of incidence and prognosis.  I suspect they may be out of date and have yet to catch up with improvements in the latest diagnostic and treatment techniques. Either that or they fail to mention the disease might only be clinically significant in much smaller percentages.

On a positive note, I sense major strides in worldwide awareness campaigns which should lead to earlier diagnosis and therefore earlier treatment for Neuroendocrine Cancer. Combine that with new and innovative treatments in debulking/removing/shrinking tumours and controlling syndromes – particularly the use of somatostatin analogues with the latter, should mean that fewer people will succumb to this additional complication. I don’t see a lot of Carcinoid Heart Disease posts on the various forums which hopefully is a good sign.

I did blog about a new treatment for Carcinoid Syndrome called  XERMELO (Telotristat Ethyl) read here.  At ENETS 2016, a report claimed that it appeared to ‘halt Carcinoid Heart Disease’ or certainly reduce the risk.  Reducing the risk sounds feasible as Telotristat Ethyl reduces the ability to manufacture serotonin to levels which appear subthreshold to that which stimulates fibrosis associated with CHD. This drug might prevent the need for valve surgery in many cases, and enable the use of bioprosthetic valves in others, without recurrent fibrosis.  You can read the ENETS poster here.

Although I’m fairly stable, I still try to get an Echocardiogram on an annual basis and am very happy to have this one in my ‘test golfbag’. The procedure is painless and takes around 20-30 minutes.  My results have always been OK.  Information on the guidelines for CHD have been a bit sparse but a new paper published has proposed an ‘Algorithm for the Screening and Investigation of CHD.

Proposed Algorithm for the Screening and Investigation of CHD This graphic provides an algorithm for how patients with metastatic (serotonin-producing) neuroendocrine tumors (NETs) should be screened and assessed for carcinoid heart disease (CHD), including, importantly, when to refer to cardiology. f/u = follow-up; NT-proBNP = N-terminal pro–B-type natriuretic peptide.

If you have time please check out this excellent video presentation on Carcinoid and Your Heart with cardiologist Dr. Jerome Zacks from Mount Sinai Hospital and the Carcinoid Heart Center, both in New York City.

Please also note that fibrosis due to excess serotonin (and other substances) can also induce fibrosis in the mesentery, retroperitoneum, pleural and pulmonary cavity and the skin. This is fully covered in my article Neuroendocrine Cancer: Fibrosis – an unsolved mystery?