64Cu-DOTATATE – a potential expansion of the Somatostatin Receptor PET Imaging for Neuroendocrine Cancer?


Edit 10 Jan 2019: RadioMedix and Curium Announce FDA Fast Track Designation For 64Cu-Dotatate.  Read more by clicking 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).

Head-to-Head Comparison of 64Cu-DOTATATE and 68Ga-DOTATOC PET/CT: A Prospective Study of 59 Patients with Neuroendocrine Tumors – http://jnm.snmjournals.org/content/58/3/451.full

PET/CT (left) and PET (right) scans of patient with intestinal NET and multiple metastases. More lesions are seen in intestinal region with 64Cu-DOTATATE than with 68Ga-DOTATOC.

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.

64Cu-DOTATATE PET for Neuroendocrine Tumors: A Prospective Head-to-Head Comparison with 111In-DTPA-Octreotide in 112 Patients –http://jnm.snmjournals.org/content/56/6/847.full

Multiple small liver metastases (>10), peritoneal solitary tumor mass, and 3 lymph node metastases shown on 64Cu-DOTATATE PET/CT in patient with pancreatic NET. No foci were detected by 111In-DTPA-OC SPECT (Precedence scanner). All findings on PET were confirmed to be true-positive. (A) 111In-DTPA-OC planar images. (B) 64Cu-DOTATATE maximum-intensity-projection image with arrows pointing at liver and lymph node metastases. Insert is fused PET/CT of peritoneal solitary tumor mass. (C) Axial CT and SPECT of liver. (D) Axial CT and PET of liver revealing several small liver metastases.

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.

Summary

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.

If you can see it, you can detect it!

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!

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177Lu-DOTA-EB-TATE – Long-lasting radionuclide therapy for advanced neuroendocrine tumors proves effective

For your information only. In the News.

Since PRRT was formally approved last year in USA and Europe (and other places), it’s triggered a whole mini-industry in PRRT variants or enhancements. An interesting study from China, a country starting to become very active in the NET world. I guess they have been active for some time given that I’ve seen their NET experts presenting at the last 2 years of ENETS in Barcelona.  In this particular study, there is linkages to the Laboratory of Molecular Imaging and Nanomedicine, NIBIB/NIH, Bethesda, Maryland in USA.

This is news of a first-in-human study presented at the 2018 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) which demonstrated the benefits and safety of a new, long-lasting type of radionuclide therapy (PRRT) for patients with advanced, metastatic neuroendocrine tumors (NETs) – 177Lu-DOTA-EB-TATE. 

How is this different from the current PRRT standard – Lutathera?

“Lu-DOTA-EB-TATE is a “three-in-one” therapeutic compound, with an octreotate peptide to find the tumor, an ‘Evans blue motif’, which uses endogenous albumin as a reversible carrier to effectively extend the half-life in the blood and substantially increase targeted accumulation and retention within the tumor, and a therapeutic radionuclide to kill the tumor cells, to finally provide effective treatment of NETs,”  …….. explains Shawn(Xiaoyuan) Chen, PhD, senior investigator, of National Institute of Biomedical Imaging and Bioengineering at the National Institutes of Health , Bethesda, Maryland.

Lutathera-177 (177Lu)-DOTATATE (trade name Lutathera), a peptide receptor radionuclide tharapy (PRRT) with radiolabeled somatostatin analogues (peptides), was recently approved by the USA FDA and the EMA for the treatment of somatostatin receptor positive NETs. It is the therapeutic part of a nuclear medicine theranostic pairing. Gallium-68 (68Ga)-DOTATATE is the diagnostic agent used in  PET/CT scans that first locates and marks the lesions for follow-up with targeted PRRT delivery directly to the tumor cells which express high levels of somatostatin receptors (SSTRs). Because the PRRT binds to receptors expressed by the tumor cells, healthy cells are unharmed. However, the peptide quickly clears from the blood through the kidneys limiting the accumulation of radioactivity within tumors and making additional treatment cycles necessary to provide the therapeutic dose.

177Lu-DOTA-EB-TATE.  This first-in-human, first-in-class, Phase I trial (ID: NCT03308682) investigated the safety and dosimetry of a novel long-lasting radiolabeled somatostatin analogue that adds an albumin-binding Evans blue (EB, an azo dye) derivative to 177Lu-DOTATATE. Albumin, the most abundant plasma protein in human blood, is a natural transport protein and has a long circulatory half-life.  This is an open-label, non-controlled, non-randomized study.

For the study, conducted in collaboration with researchers at the U.S. National Institute of Biomedical Imaging and Bioengineering, 8 patients (6 men and 2 women ranging in age from 27 to 61 years old) with advanced metastatic neuroendocrine tumors were recruited from Peking Union Medical College Hospital and the Chinese Academy of Medical Sciences in Beijing, China.

Each patient underwent whole-body 68Ga-DOTATATE PET/CT. Five of the patients then accepted intravenous injection with a single dose of 0.35-0.70 GBq of 177Lu-DOTA-EB-TATE within one week, and were monitored at 2, 24, 72, 120 and 168 hours after 177Lu-DOTA-EB-TATE administration with serial whole-body planar and single photon emission computed tomography (SPECT)/CT images acquired. The other 3 patients accepted a dose of 0.28-0.41 GBq of 177Lu-DOTATATE and were monitored at 1, 3, 4, 24 and 72 hours with the same imaging procedures. Complete physical examinations, including vital signs, blood count, biochemistry, and immunology analyses were performed immediately before and 1, 3, and 7 days, as well as 3 months, after treatment.

Administration of 177Lu-DOTA-EB-TATE was well tolerated, with no adverse symptoms reported throughout the procedure and follow-up. The total effective dose equivalent and effective dose were 0.2048 ± 0.1605 and 0.0804 ± 0.0500 mSv/MBq for 177Lu-DOTA-EB-TATE and 0.1735 ± 0.0722 and 0.0693 ± 0.0317 mSv/MBq for 177Lu-DOTATATE. The liver, kidneys, bone marrow and total body received slightly higher doses (mGy/MBq) with 177Lu-DOTA-EB-TATE than with 177Lu-DOTATATE, while the spleen received lower doses with 177Lu-DOTA-EB-TATE. Blood clearance of 177Lu-DOTA-EB-TATE was also slower. Most importantly, 177Lu-DOTA-EB-TATE lasted in the tumors more than 4 times longer than 177Lu-DOTATATE.

Jingjing Zhang and Zhaohui Zhu of Peking Union Medical College Hospital point out, “By introducing an albumin binding moiety, this long-lasting radiolabeled somatostatin analogue has remarkably enhanced uptake and retention in SSTR-positive tumors, which is important to increase the therapeutic efficacy in patients. With proper selection of patients with advanced metastatic neuroendocrine tumors, 177Lu-DOTA-EB-TATE has great potential to be a highly effective treatment, while providing a safe dose with less frequency of administration than is possible with 177Lu-DOTATATE.”

FIGURE: SPECT/CT of a 45-year-old male patient with advanced NETs and multiple liver metastases – persistently retained in the tumors after 168 hours

Scans were done at 2, 24, 72, 120 and 168 hours after the administration of 177Lu-DOTA-EB-TATE. The radiopharmaceutical cleared from the blood pool over time and persistently retained in the tumors (arrows). Credit: J Zhang et al., Peking Union Medical College Hospital, Beijing, China; X Chen et al., Laboratory of Molecular Imaging and Nanomedicine, NIBIB/NIH, Bethesda, MD

Sources:

Abstract 118: “Safety, Pharmacokinetics and Dosimetry of a Long-lasting Radiolabeled Somatostatin Analogue 177Lu-DOTA-EB-TATE in Patients with Advanced Metastatic Neuroendocrine Tumors: A Phase 1 First-in-human Study,” Jingjing Zhang, MD,PhD, Yuejuan Cheng, MD,Hao Wang, MD, Jie Zang, PhD, Fang Li, MD, Chunmei Bai, MD, and Zhaohui Zhu, MD, Peking Union Medical College Hospital; Gang Niu, MD, Orit Jacobson, PhD4, and Xiaoyuan Chen, PhD, U.S. National Institutes of Health, Bethesda, MD. SNMMI’s 65th Annual Meeting, June 23-26, Philadelphia.  Link to SNMMI Abstract

Other articles in this series:

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

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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!