PD-1 checkpoint inhibitors

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The recent discussion of immunotherapy under “Going Commando” has rekindled my experience of Pembrolizumab, a PD-1 checkpoint inhibitor.

Our immune systems have T cells that help fight off diseases. Cancer cells that express PD-L1 escape this by binding to PD-1 receptors on the T cells. By doing this they are able to hide from the immune system, using the same mechanism the body uses to create immune privileged zones around critical organs.

PD-1 checkpoint inhibitors are offered to patients who have tumours that meet a threshold percentage of at least 10% of PD-L1 cells within the tested sample (plus other criteria). In my case, TNBC, they are available in the metastatic setting or for advanced presentation of early stage primary cancer. I had it in the metastatic setting, with spread to my liver.  The immunotherapy removes PD-1, thus allowing the immune system to ‘see’ and work on the cancer. Of course it also removes the immune privileged zones around critical organs too. As such, it can be both a game changer in cancer treatment, and also life threatening. 

I started Pembrolizumab in May 23. It was a relatively recent authorisation for TNBC, so my breast oncology consultant was new to it. I was one of 2 patients starting on it. I was sufficiently worried about the adverse effects to arrange to speak to an oncologist working in melanoma, where it has been in use for much longer. Her own experience was consistent with the patient leaflets, with skin rash being a frequent issue, there being some cases of colitis, but most other adverse events being very rare.  The user reviews on the American drugs.com site showed the usual bias towards people who had suffered adverse effects with a typical review being “it killed my dad but the cancer had also been killed”. 

The first 3 infusions were trouble fee. Infusion 4 led to a rash, easily treated with topical steroid, emollient and antihistamine. Infusion 5 was crunch point. The first inkling I had was a raging thirst on the day I had my bloods done for the chemotherapy I was due to have the next day. (For TNBC they kickstart it with Paclitaxel or NAB-Paclitaxel alongside). By the evening I had been admitted to hospital with acute kidney nephritis. Thyroid function had also failed. Started on high dose steroids, which I am still using via a slow weaning programme, more issues emerged as the steroid dose reduced. Pneumonitis. Low level colitis. Inflammation in my spine affecting nerves in my left side limbs. Some 6 months on I am still managing these consequences. On the other hand a scan just after my last treatment showed my larger tumour had shrunk to a seventh of its volume and the smaller one to a third. A scan 3 months after that showed them still dormant and unchanged in size. I have subsequently had the residue ablated. I am realistic to know this isn’t the end of it but I appear to have survived both the upside and downside of the treatment, albeit with ongoing health consequences. I have no regrets but would be wary of recommending the treatment to others. 

  • Hi  

    Thanks for this - very interesting. Pleased it's worked out for you.

    A x

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  • Hello Coddfish, I knew my time in healthcare would be useful in retirement, a real eye opener, sorry to hear about the negative impact on your health, but the positive is amazing, best wishes going forward,

    Eddie

  • Thanks for this. As someone who is having a bit of a complex reaction with Pembro, in that my markers initially went down and then started to increase, plus my latest scan appeared to show some progression, I’m following these conversations on immunotherapy with great interest. My consultant thinks it’s still too soon to change course, as my health generally shows a different story. Tomorrow is my 5th IV, I am holding out for good news next scan. Otherwise it’s back to chemo for me. 

  • Hi Coddfish, I could almost written a lot of what you have said but I haven't had immunotherapy as it hadn't been approved when my oncologist was looking for anything that might give me some extra time. With me it was a Target drug for Malignant Melanoma which was being trialed. 
    I am still living because of the drug which has now been licensed but I have, like you, to live with the consequences of the side effects. Knowing what I know today would I have gone through with starting the Trial Drug? You better believe it! It is difficult and some days I hear myself saying "I can't do this anymore! Then one of our grandchildren pops  in and that makes me strong again!

    Love Annette x

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