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Barree

 

                                                               THERA-NOSTICS

                               Targeted Theraputic  LU177- PSMA -617               DIAGNOSTIC  COMPANION  GA68-PSMA 11 - Pet/CT

 PSMA -Many prostate cancer cells have a protein on the surface called PS MA (prostate specific membrane antigen).

 PSMA 6I7 Ligand is a small peptide (molecule ) with a high binding affinity for PSMA.

When injected into the bloodstream it looks for the PSMA exuded on the surface of the prostate cancer cells and bonds to it. This ligand not only bonds to PSMA  –  it also bonds to Lutetium 177 and Gallium 68 (Ga 68).

Gallium 68 is a radioactive isotope. From the time it is made radioactive in the hospital laboratory, it only has a half life of 68 minutes.

Lutetium177 is also a radioactive isotope which when made radioactive has a half life of 6.64 days.

To determine if you are suitable for Lutetium  treatment  

Firstly a Gallium 68 scan is done

Gallium 68 is mixed with the PSMA 11 Ligand, this blend is then injected into the bloodstream. The mixture circulating through the bloodstream is attracted to the protein and starts to build up on the surface of the cancer cel ls (in much the same way as  iron filings are attracted to a magnet).

If there is no PSMA on the cancer cells  –  you are NOT considered to be PSMA Avid  -  the Ligand /Gallium 68 blend will just keep circulating and without any PSMA to adhere to, it will be passed in your urine. When the scan is done  –  there will be nothing to see  –  so if you are given a dose of Lutetium 177 / ligand blend  it  too will  do nothing, i t will just pass through the bladder and be excreted with your urine.

As the Lutetium177/ Ligand blend will have no PSMA to build up on, you will  NOT be considered suitable for  treatment with Lutetium177.

If you are PSMA avid  

The Ligand /Gallium 68 blend wi ll keep circulating and be attracted to the protein on the surface of the cancer cells and continue  to build up on the surface. This will show up on the scan so the location of the PSMA avid cancer cells can be seen.

In this case you maybe suitable for treatment with Lutetium177  but  suitability still depends on the results of an FDG scan.

Secondly a F18  FDG (Glucose ) scan is done

If there is no PSMA on the surface of the cancer cells, the Ga68 scan will show nothing but there could still be cancer present – cancer which is not showing up. This is why it is important to have a F18 FDG (Glucose ) scan. This scan can show cancer which does not exude  PSMA  and in this case, treatments other than Lutetium 177 would have to be considered.

When the two scans do not show prostate cancer in the same position, the scans are considered to be discordant  -  in which case you are not considered to be a suitable candidate for treatment with Lutetium177    -  it just won’t work.

When you receive a Lutetium177  injection — it starts circulating through the bloodstream, building up on the protein on the surface of the prostate cancer cells and starts killing the cells beneath the protein.  The radiation from this (Lu-PSMA) beta mixture only penetrates about 1mm ,so it will not damage the surrounding non-cancerous tissue.

It keeps working flat out for approx 7 and a bit days, and then slowly ceases working over the next few weeks as the radioactivity of the Lutetium177 decays

Further Ga68 Scans will show the results of the Lutetium177   treatment.

 

 

 

 

 

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Patrick Turner
42 minutes ago, Barree said:

THERA-NOSTICS

                                     Targeted Theraputic  LU177- PSMA -617      DIAGNOSTIC  COMPANION  GA68-PSMA - Pet/CT

Thank goodness you have explained the technicalities of theranostics a lot better than I have repeatedly tried to explain to a lot of ppl online.

Theranostic treatment is gaining popularity because it works more than it does not work compared to a number of other things one might try when ADT, Cosadex, Zytiga, Xtandi and chemo fail to prevent Pca growing to put  man into palliative care and face his end.

I don't know if I have had F18 FDG scan but scans I have had were all PsMa Ga68 PET / CT scans and I was told the CT part of scan did not show anything that was not in PET part of scan and nobody has said I have Pca that has low or no PsMa avidity where Lu177 will not work.

I had Psa 25 before beginning Lu177 last Nov, and then after No 3 Lu177 shot I began Xtandi, and then Psa was 1.7, and lower after No 4 Lu177, Psa went lower and now Psa is about 0.4 ( 3weeks ago ) and seems like I am getting a good response. I saw the Hoffman report from PeterMac about patients with non PsMa avid Pca, and I am not sure what exactly could be done for them. But I also saw where I could get more Lu177 in future if / when Psa rises again if PsMa scan shows avidity so that instead of getting maybe 14 months of life extension I might get 3.5 years.

What are your thoughts?

Patrick Turner.

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DesG

Does Chemo and ADT have to have failed before this treatment, or can you access earlier?

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Barree

Hi Patrick, My thoughts are that as long as the scans continue to show you are responding to additional Lu177 treatments there is every possibility  that you will get a corresponding life extension. As far as I am aware some patients in Germany have had up to 9 infusions.

 

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Bruce

Thanks Barree a succinct explanation, the best I've read yet.

I had a radical prostatectomy 9 years ago. In late 2017 I found the cancer had reoccurred in my lymph system and had 6 weeks of radio-therapy at St Vincents Sydney. Following the radio-therapy my PSA dropped to 5 over 3 months and then started to climb. A scan showed a new spot had developed in a different part of my lymph system. It was suggested that I should see Dr Nat Lenzo at Theranostics before committing to chemo. I had one infusion of Lu177 18 months ago. My 3  monthly PsMa scans have been clear since, so I'm feeling very fortunate. I'm now moving to a scan every 6 months.

Bruce

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Barree

Hi Des,

 The TheraP trial looked for patients where their:-   prostate cancer had spread to other parts of the body and  had grown despite previous hormone treatment and treatment with docetaxel.

Their next step would normally have been to consider further chemotherapy with cabazitaxel. However I am sorry to say that this trial is now full. I understand the last patient to be recruited was signed up about a week ago.

The only options now are to obtain Lu177 treatment commercially or wait and watch the up coming trials to see if you are eligiable for any of them.

Cheers, Barree

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John_H_T

Hi Barree,

Great work on explaining this treatment.

I have been reading about it recently but could not find anything explaining it so succinctly.

Well done and thanks.

Regards

John

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DesG

Thanks for the info - Barree -any idea the costs of obtaining commercially - would the best option be getting a referral to Louise Emmett? Although I've probably missed the boat to try this - had my ADT implant on Friday. Have sent off an email to her dept. at St Vincents - will see what they come back with.

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Barree

Hi Des,

Your idea of a getting a referral to Prof Louise Emmett makes a lot of sense.

On one occasion recently one of our members managed to get on a Lutetium177 trial being run by Prof Emmet which had not been widely publicized.

 Your email to her is a good starting point. 

Commercially The first Lutetium infusion including scans could be somewhere in the region of $12000.00 and subsequent infusions and scans about $11000.00. As Patrick Turner has mentioned in one of his recent postings the addition of Enzalutamide to Lutetium177 as suggested by Prof Emmet proved most beneficial for him. The addition of Enzalutamide will of course add to the costs mentioned above but I should hasten to add the addition of Enzalutamide has not as yet been proven to be beneficial for all patients.

 Most times 4 infusions of lutetium are required but Bruce who has just posted his treatment history (see above) has indicated he has benefited from just one infusion.We all respond differently.

Prof Emmet is not far off conducting a trial using Enzalutamide with Lutetium 177. As I don’t know your prior treatment history I don’t know if you will be eligible for this trial but if you are  - this will be a great opportunity  to get this ground breaking treatment on a trial at little or no cost.

I hope that you are eligible for it.

Cheers,

Barree

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DesG

Thank you so much Barree. Will give them a few days to respond to my email - then follow up with a call. Fingers crossed the planets will align for me - could do with a break. I inherited every crappy gene from both my parents, need some luck. 

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DesG

I received a reply fro Louise Emmett - her response - 

"There are a couple of trials due to start in that space - but not going yet - probably next year. So the Chemotherapy and LHRH planned sounds a good place to start.

 

We do self funded treatment as well at Vinnies - but that is not yet shown to be better than chemo and currently all our trials are for men in whom treatment has failed."     So I head off to the Oncologist at Westmead 24th October to get things going - that is, Chemo and ADT regime. Have had the ADT implant done - on pain killers and having second shot of radiation on a still painful spot on Tuesday. 

 

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