I've done a bit of research this afternoon, and one comparable...

I've done a bit of research this afternoon, and one comparable in-human study which used iron oxide nanoparticles is that of Combidex (link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5763341/). The patients were injected with 2.6mg Fe/kg of body weight, and of the 310 patients only 8 had adverse effects that were minor to say the least (see below).

In comparison, in this article from Sandia from 2018 (a lab in the US which IBX collaborated with to design nanoparticles specifically to be used in our trials) - https://share-ng.sandia.gov/news/resources/news_releases/magnetic_nanoparticles/, then Chief Nanoparticle Scientist at IBX, Erika Vreeland (who also worked on the initial studies on this imaging technique with Dr Edward R. Flynn) states that we would only require injecting at most 1mg of nanoparticles for each patient (regardless of body weight!) for our MagSense tests. This is dramatically less than what the study with Combidex required, and from this I am confident that patient safety should not be an issue in relation to our SPION contrast agent.

Now, from what I understand, Combidex was investigating a similar use of iron oxide nanoparticles in imaging cancer with MRI, and indeed demonstrated some efficacy in doing so. However, their method was not targeted like ours, and ultimately was rejected by FDA's ODAC for the following reason: (source: https://prostatecancerinfolink.net/2010/03/24/the-demise-of-combidexsinerem/)

The above suggests that although their product was successful in imaging lymph nodes via MRI, it did not do well in differentiating between cancerous and non-cancerous lymph nodes. MagSense however is designed to only tag and detect cancer cells, and nothing else!

Take the above for what you will, but I sincerely believe that there is a solid investment case here, in a technology that is well-researched and fairly de-risked at this point (toxicology studies, Siemens collab etc).