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Does intake of Keytruda help in treating pleural mesothelioma?

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Posted on Wed, 25 May 2016
Question: My husband is about to start on a clinical trial using Keytruda for a recurrence of pleural mesothelioma. I am keen to know what Keytruda actually does, or hopefully does in his case. I know it works on stimulation of the immune system, and I think it has to do with certain proteins expressed in the tumour cells that are not killed by the bodies immune system in his case. But would be glad if you could help me understand the exact action of this drug.
doctor
Answered by Dr. Shafi Ullah Khan (2 hours later)
Brief Answer:
Mechanism of action explained.

Detailed Answer:
Thank you for asking

I read your question and i understand your concern. I am sorry for the troubles of your husband's mesothelioma and i wish you both luck with your new trial of keytruda. Keytruda is a monoclonal antibody called pembrolizumab. It is approved for use in melanoma and small cell lung cancer. Mesothelioma is under trials. Our body produces defence cells called lymphocytes which make sure body's own system is not hurt and foreign intruder of any kind, an organism, tumor, abnormal cell is lysed. The patrol in the body and use their unique ID Programmed cell Death PD 1 to identify body's own cells which have counteracting ligand to approve it named PD L1. So which ever cell in body have this PDL 1 identity with them T cells spare those and consider them of body's own.

Tumor cells for which pembrolizumab is used, do the same and mimim bodys own ID PDL1 and thus manage to spare themselves of the destruction by T cells. This antibody drug is to make sure this bond is broken for ever and it targets these PD1 and PDL1 sites.

I hope i explained the mechanism of action of this drug simple enough to make you understand. Take good care of your husband and yourself and dont forget to close the discussion please.
Regards
Khan
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Shafi Ullah Khan (1 hour later)
Hello Dr XXXXXXX

Thankyou for your answer....I think I am beginning to understand!

I have a few more questions to get it clear in my mind.....

Is the PD1 unique to every person?

Is PD 1 the name of the lymphocyte, or the part of the lymphocyte that destroys abnormal cells?

From what I already know, the T cell is a type of lymphocyte, what does this have to do with PD1?

Is the PD 1 cell the enemy or the friend? Or is it named PD1 as it is programmed to destroy any abnormal cell?

Do the lymphocytes , or T cells, in a well person, select the persons correct PD1 cells to stay alive, and reject any others?

So am I right in thinking that a tumour cell is able to mimic the body's own PD 1 cell, and therefore is not considered an enemy cell by the T cell?

Do these things happen in any abnormal tumour growth in the body, or only in certain cancers?


Hello....I do not have a reply yet to my questions.

Were the questions too hard? Should I ask another doctor, maybe an oncologist?

Kind regards

XXXXXX
doctor
Answered by Dr. Shafi Ullah Khan (14 hours later)
Brief Answer:
Explained

Detailed Answer:
Thank you for getting back to me

PD ( program cell death ) ligand is a receptor at the t lymphocyte surface. Consider it a scanner to detect fake passport ( absent PD1 ligand receptor ) in outsider cells. Mesothelioma manages to have a passport and thus spare itself of the detection and survives. This pembrolizumab acts against these fake passport identities and make them susceptible to breakage by t lymphocytes.

So

1) PD is not t lymphocyte. Its a cell membrane receptor of t lymphocyte.

2) Yes they are unique to every human body in composition and genome.

3) PD receptors are on lymphocytes and PDI ligands should be present on body own cells, if not them they die, this is called programmed cell death. Every cell lose this ligand ( passport ) once the time is near finishing decided by genetic makeup. Cancerous cells don't succumb and they get rebellious and stay with PD1 and thus lead to malignancy. As we know, cancer is uncontrolled production of cell. Nutshell its a lock and key model.

I hope it helps.
regards
Khan
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Shafi Ullah Khan (6 hours later)
Hello Dr XXXXXXX

Thank you for your reply, I now understand the basics of the actions of Keytruda, T cells, PD1, and PDL1. You must have spent a lot of time researching this answer for me, as my husband's oncologist was not able to make me understand!

I will close after this and give you an excellent review!

Thank you again!
doctor
Answered by Dr. Shafi Ullah Khan (34 minutes later)
Brief Answer:
:)

Detailed Answer:
You are welcome miss XXXXXXX

I appreciate the review and kind words.

Regards
Khan
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Answered by
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Dr. Shafi Ullah Khan

General & Family Physician

Practicing since :2012

Answered : 3613 Questions

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Does intake of Keytruda help in treating pleural mesothelioma?

Brief Answer: Mechanism of action explained. Detailed Answer: Thank you for asking I read your question and i understand your concern. I am sorry for the troubles of your husband's mesothelioma and i wish you both luck with your new trial of keytruda. Keytruda is a monoclonal antibody called pembrolizumab. It is approved for use in melanoma and small cell lung cancer. Mesothelioma is under trials. Our body produces defence cells called lymphocytes which make sure body's own system is not hurt and foreign intruder of any kind, an organism, tumor, abnormal cell is lysed. The patrol in the body and use their unique ID Programmed cell Death PD 1 to identify body's own cells which have counteracting ligand to approve it named PD L1. So which ever cell in body have this PDL 1 identity with them T cells spare those and consider them of body's own. Tumor cells for which pembrolizumab is used, do the same and mimim bodys own ID PDL1 and thus manage to spare themselves of the destruction by T cells. This antibody drug is to make sure this bond is broken for ever and it targets these PD1 and PDL1 sites. I hope i explained the mechanism of action of this drug simple enough to make you understand. Take good care of your husband and yourself and dont forget to close the discussion please. Regards Khan