Adverse reaction to keytruda: Report any symptom change

Posted by jmp1514 @jmp1514, Oct 25 5:55am

Keytruda has been an amazing treatment for my husbands stage 4b esophageal adenocarcinoma. He started FOLFOX + keytruda + trazamera in February 2023. His last scans showed no active disease.
Mid September he had sudden onset of weakness, muscle/joint pain, dizziness and lethargy while we were on a “celebratory” cruise to Alaska.
To make a long story short(er)-Per the literature Keytruda can cause your immune system to attack normal organs and tissues in any area of your body and can affect the way they work including “hypothyroidism or hyperthyroidism, thyroiditis, hypophysitis, primary adrenal insufficiency, and insulin-dependent diabetes mellitus”.
These can be life threatening.

My husband was diagnosed with adrenal insufficiency, and now hypothyroidism. Both are being medically managed and after a 6 week pause he has restarted treatment.

I am grateful to his Mayo docs who always investigate immediately when new symptoms are brought to their attention. Many providers might have attributed his symptoms as just cancer symptoms.

My main reason for sharing this is to encourage others to monitor and report ANY symptom change. It could save your life.

Interested in more discussions like this? Go to the Esophageal Cancer Support Group.

while Keytruda is an amazingly effective PD-1L targeted therapy, it's use may also cause "off-target" effects. It's use in patients with pre -existing co-mobidities such as hyprt/hypothyroidism, and various autoimmune diseases such as psoriasis, lupus, MS is considered high risk but supposedly manageable with the concomitantly administered steroids to help managed excessive activation of systemic immune effects. It's use may also cause various cardiovascular events. If you listen to the various commercials for Keytruda there is a rapid description of an extensive list of potential adverse events that may occur with it's use. In my case, after my 3rd dose of Keytruda which had been added to my FOLFOX chemo regimen, I experienced a pseudo relapse and neurotic progression of my RRMS which had been in stable remission for >5yrs. I was nearly completely paralyzed and spent close to 3 months in the hospital and rehab. I went from being fully ambulatory to being in a wheel chair. In addition, I developed psoriasis and psoriatic arthritis. While Keytruda's off-target effects extracted a heavy toll by inducing increasing my physical disabilities, it did have a remarkable effect on my ESCC primary tumors and metastise which thus far seems to be sustained as evidenced by recent PET-CT-MIPs scans. I think the trade off was worth it. That said everyone who is offered Keytruda, Optdevo or other targeted adjuvant immunotherapies take the time tofamiliarize themselves with their potential risks and discuss them with their oncology care team.


Well said.
You certainly had
a tougher road than my husband. I read a study suggesting that those patients who experience an adverse event have more successful outcomes in the treatment of their cancer.

I would suggest that anyone on Keytruda or similar drug keep the possibility of an adverse reaction in the back of their mind.


Absolutely! See my prior comments on the risks and rewards of the Keytruda and other immuno-oncology adjuvant therapies. I would strongly advise that anyone who is prescribed Keytruda, Opdivo, etc to carefully read the drugs package insert (PI) which list all or most of the common adverse events of the drugs that were observed in patients who recieved the drug during its clinical development trials. The frequency of safety/side effect issues (adverse events or AEs) often arise or increase with many drugs' use after they have received FDA approval. They are more reflective of the drugs' true safety profiles as they now being used to treat larger numbers of patients in the general population who are afflicted with the drugs' particular targeted disease. The patients who participated in the clinical development trials for the drug were highly selected via a process that utilizes rather specific and restrictive inclusion and exclusion criteria for participation in the trial. Often, the trial populations patients are not truely reflective of the general population who may have other medical complications/co-morbidities/existing conditions.

Any new drug's true safety profile only begins to come into clearer focus after it's launch into the marketplace and it's wider uptake and use/prescription by health care providers.

Please sign in or register to post a reply.