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The largest study to date of a “cancer vaccine” plus one of the immunotherapy drugs that has revolutionized cancer treatment found that they kept patients’ tumors in check longer, on average, than drugs alone, but that the benefit was still only a few months for two forms of cancer, study sponsor Neon Therapeutics reported on Monday.

It was a hint that an experimental therapy often described as the next great hope for immune-based approaches to fighting cancer will not be a silver bullet.


In the study, the 21 patients with metastatic bladder cancer, and the 27 with metastatic non-small-cell lung cancer, had a median progression-free survival (PFS) of 5.6 months, meaning half saw their tumors grow or spread before that time.

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  • In 2017 I began treating at Mass General Hospital with a series of infusions
    using the immunotherapy drug, Keytruda, to treat melanoma. After 3 series of infusions, beginning in January 2017 and ending in October 2017, the Keytruda had no effect on the melanoma but did destroy my immune system resulting in 3 different hospitalizations in the winter/spring of 2018. I recovered from the non-infectious ulcerative colitis, the pneumonia and SVR infection and the cellulitis. The melanoma was surgically removed in February, 2019. However, I am now disabled as I have been left with Chemo-induced peripheral neuropathy of both my hands and feet, for which there is no cure. . I am no longer independent and need help in my day to day personal care.

    Keytruda basically poisoned me and destroyed my life.

  • You cannot say that adding the vaccine prolongs PFS without a control arm. It is impossible to tell whether there was a benefit to adding the vaccine in this trial – use of the word “longer” leads to the question of longer than what? Longer than seen in a different trial of different patients with probably different doctors, different baseline criteria, different treatment at different centers. Longer than the investigators predicted based on prior data. PFS is a highly variable outcome driven largely by the baseline characteristics of the treated patients and especially fraught when only a small number of patients are included. I would agree, however, that the PFS data are promising and justify more robust studies.

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