Vivos Inc (RDGL)

[kayak_wench]

I finally found information on alpha versus beta I have been looking for in
https://www.avmi.net/services/radiotherapy/brachytherapy/

From this article it doesn't seem that alpha is a better choice at all, not sure why recent competitors are adopting it and talking alpha particle treatment up. It also validates the earlier posters conclusion of gamma being 'just right'.
"The suitability of a radionuclide for brachytherapy is determined by its half-life and by the type, energy, and branching ratios of its emissions. Radioisotopes emitting beta and gamma rays are usually employed in brachytherapy as they have more penetrating power than alpha rays. Although beta rays do not penetrate more than 3-4 mm, they are useful for the treatment of superficial lesions like those of the skin and eye. Gamma emitters are usually preferred in brachytherapy because of their penetrating power."

It describes 3 applications methods: surface moulds, interstitial implants, and intracavitary insertions.

I'm pretty sure surface application of Radiogel via a paste mixture is the first route being applied for approval by the FDA (versus implanting a gel). Note it says in traditional brachytherapy treatment surface moulds are being replaced with electron beams and superficial x-rays (probably because it can't be easy to build a mould that is suspended above a skin lesion). An electron beam or x-ray probably takes special expensive equipment. So instead of building a mould or buying and learning to operate an electron beam a doctor using Radiogel just orders some Yi-90 paste, surrounds the topical cancer with plastic adhesive covering to shield healthy tissues, smears paste on, then covers with plastic adhesive until fully treated. No other brachytherapy product can be delivered via an absorbable paste (they all require devices adding complexity and cost). I believe the company is hoping surface applications can be easier to get approved by the FDA than anything inserted internally.

The AlphaDart (as apparently all other existing brachytherapy methods) have to have a special applicator for different application areas. Compare that to IsoPet and Radiogel that use standard syringes (which all doctors are comfortable handling).

Why do I care about this information, because now I can comfortably discount AlphaDart as a technically comparable competitor because it lacks advantages in several areas (complexity, cost, and likely efficacy)

Another thing this article should make obvious is that there is zero doubt of the efficacy of Yi-90 in treating cancer. Zero. This is all about getting the device approved not about whether Yi-90 is an effective treatment for cancer. Its not perfect, but nothing is (yet), it seems as good as any other isotope based treatment.

I don't have time today, but I want to follow up with Vivos PRs to see if some of the testing they are going with veterinarian clinics are for surface lesions given that is the first application being pursued with the FDA.
Will/could the FDA may be concerned a patient will remove the plastic covering on a topical Yi-90 paste and be exposed to the product. Yes that last thought will make most think I am against the product, but I believe it is a valid question to pose.