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Hi David,
My sympathies: you have been through a lot of treatment and now face more.
I have not had bispecifics but I am geeky enough to read a lot 😀.
Belantamab gets the immune system to attack the BCMA antigen. Since that has stopped working, that probably means that your myeloma cells have adapted their BCMAs (similar to bacteria getting resistant to an antibiotic). That would make the bispecifics teclistamab and elranatamab less effective.
The other approved bispecific is talquetamab, which targets the GPRC5D antigen instead. It’s my best guess that that is what your consultant is thinking about.
The regime for bispecifics is that you would be given a few “step up” doses over a couple of weeks to see how you get on and to let your immune system respond steadily. Then you would get regular doses, typically weekly for some months then less frequently.
Side effects: Warning you may not want to read the rest of this!
Unfortunately, people also have GPRC5D antigen in cells on the tongue, skin and nails, so a metallic taste and skin rashes are common, (as well as changes to nails such as brittleness).
Then there is a lot of infection risk.
There is cytokine release syndrome, where you body attacks myeloma cells too enthusiastically and your body struggles to cope (that’s why the step up is important – the attack is more gentle on your body).
Then there is neurological toxicity. Less common but can include confusion and brain fog.
Blood counts can become low, although transfusions can help with that.
Regards
Rabbit
rabbit.
Hi David,
As an ex-scientist, it is relatively easy for me to find data (I generally know where to look) but I also know that that isn’t always the point.
Two issues come to mind in terms of bispecific side effect data and its relevance:
– As you said yourself, there are 3 bispecifics. Although I have stated above why I think that the relevant one for you is Talquetamab, your consultant may think differently.
– The clinical trials were done a few years ago. Since then, things have moved on for the better, so the data on side effects is more adverse than what you would face. The “step up” that is now being done was developed to reduce the probability and severity of cytokine release syndrome (CRS), for example. Tocilizumab, a drug that blocks inflammatory signaling and can rapidly control CRS symptoms, is now routinely given. Also it happened that some trials were done when Covid 19 was at its worst, so there were a lot of severe infections: hopefully you are vaccinated, and Covid has subsequently become much milder anyway.
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