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USA FDA approves Xtandi (enzalutamide) for use with hormone sensitive metastatic prostate cancer


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Jim Marshall (not a doctor) said ...

This post from the "New" Prostate Cancer Infolink reports that the FDA (Food and Drug Administration) in the USA has approved the use of Xtandi (Enzalutamide) for metastatic prostate cancer which is still responding to standard hormone therapies.

Previously, men with metastatic prostate cancer had to wait until their cancer did not respond to standard hormone therapies - that is until their PSA was rising while a standard hormone therapy kept their testosterone at very low levels (castrate levels).

Note that Enzalutamide has not been approved for the treatment of any form of advanced prostate cancer when used on its own without a standard hormone therapy.

Men outside the USA will have to wait for approval from their own government drug bodies - in Australia for approval by the Therapeutic Goods Administration (TGA) for this use, and for the Pharmaceutical Benefits Advisory Committee (PBAC) to see whether it will go on the Pharmaceutical Benefits Scheme (PBS).

 

Standard hormone therapies include:

Agonists: Zoladex (Goserelin), Lupron (leuprorelin), Eligard (leuprolide), Lucrin (leuprorelin acetate),  Suprefact/Suprecor (buserelin), Synarel (nafarelin), histrelin (Supprelin), Suprelorin/Ovuplant (deslorelin), Triptorelin (diphereline); and the

Antagonist: Firmagon (degarelix).

... end Jim

 

With permission from the "New" Prostate Cancer Infolink:

FDA approves enzalutamide for treatment of metastatic HSPC

Posted on December 17, 2019 by Sitemaster
 
5 Votes

Yesterday the U.S. Food and Drug Administration (FDA) approved the use of enzalutamide (Xtandi) for the treatment of metastatic, hormone-sensitive prostate cancer (mHSPC) — also known as metastatic, castration-rsensitive prostate cancer or mCSPC.

 

For the full media release announcing this approval (from Pfizer and Astellas, the manufacturers and marketers), please click here. The approval is based on data from the ARCHES trial that were initially announced at the Genitourinary Cancers Symposium in San Francisco, last February, and published by Armstrong et al. in the Journal of Clinical Oncology in July.

Note in particular that this approval of enzalutamide for the treatment of mHSPC is only when used in combination with as standard LHRH agonist such as leuprolide acetate. Enzalutamide has not been approved for the treatment of any form of advanced prostate cancer when used on its own.

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Patrick Turner

I began ADT in 2010 after failed RP at age 62. I had the normal progression of add-on drugs after Lucrin failed in June 2016. First was Cosadex, (bicalutamide) which worked to suppress Pca for 6 months, then Zytiga, (arbitererone) which worked for 8 months, and then I had 5 shots of chemo, which did not suppress Pca.

At one point my oncologist wanted to switch me to Xtandi, (enzalutamide) but Australian PBS rules outlawed this so I had to accept chemo.

But after chemo failed I qualified for Lu177, and Psma scans showed I might respond well, and Psa went from 25 at Nov 2018 to 0.30 now, so a good response after 4 shots finishing last May. When I had No 3 shot, a Professor Louise Emmett was looking after me in nuclear clinic at Waratah private hospital in Sydney. She is a leading Pca researcher at St Vincents and was filling in time between trials by doing clinical work. There were only 4 patients for her day, so I got to speak to her for a long time. She was sure that men who have progressed through the normal procession of HT drugs and chemo that they will become re-sensitised to arbiraterone or enzalutamide so she spoke to my oncologist and I have had enzalutamide ever since last April and all paid by PBS.

It is uncertain now just what is reducing my Psa now, but Dr Emmett said the enzalutamide stimulates the expression of PsMa by Pca cells thus making Pca more able to attract more Lu177 at Pca cells that make Lu177 more effective. I had slight Psa reduction after No 3 Lu177 shot, when I was not yet taking enzalutamide, but after no 4 shot of Lu177, I had full amount of enzalutamide level and the Psa nose dived.

Dr Emmett got funding for her trial of Lu177 + enzalutamide approved on the very day she saw me. In other words, she was able to show the combination of Lu177 plus enzalutamide was highly likely to work in clinical practice as some doctors had noticed, so a trial to confirm this followed. 

I have no idea when I will have to stop taking enzalutamide, but at present I will keep going with it while nobody says I cannot have it, and Psa remains low. 

My follow-up PsMa scan in last August said that bone mets were healing, no new mets, and soft tissue mets had all become absent, ie, to small to be seen on such a scan. The radiology said they could not see any Pca lesions in CT part of scan that were not also visible in PET part of scan, and docs are not worried that I have a lot of mutated Pca.

Side effects of dry mouth from Lu177 are intermittent, and happen sometimes at night, or when going hard on the bicycle on a long ride of 60km+, but its not a big problem. I have not noticed any side effects of enzalutamide. My GP said I have a 12% cardio vascular risk, ie, negligible, and I have a very good set of blood test results. 

 

There is a huge effort to further understand PsMa expression by Pca by Dr Hoffman at Peter Mac so that more men who initially look to be suitable for Lu177 might get a better benefit. Some get no benefit, some get a partial benefit, leading to Pca progress within a year or two and a pile of what is maybe experimental treatment with low efficacy rate. If my Pca flares up to become a threat again, I hope there may be some new therapy to deal with it and with more certainty. I am now 72, and it would be nice to live to 82.

 

There's always a chance of bad surprise, and I had one of these a month ago with adhesions of small intestine to previous surgery scar tissue formed after my failed attempt to remove PG in 2010. I just had a minor op to sever the adhesions, but they are likely to form again. I had The Most Miserable 11 Days in hospital, and I lost 8kg. I am slowly putting weight back on, and average cycling speed is 18kph, not the 24kph I did before the blockage. I still have a long way to recover.

I can only wonder if the forced starvation and loss of all my gut bacteria may have accelerated the demise of my Pca, but I doubt I'd be that lucky; Pca can be a robust enemy, able to survive well no matter how weakened a man becomes.

Patrick Turner. 

 

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