"Previous data from the trial reported that 107 participants received the mRNA vaccine and Keytruda treatment, while the remaining 50 only received Keytruda. At the two-year follow-up, 24 of the 107 (22 percent) who got the experimental vaccine and Keytruda had recurrence or death, while 20 of 50 (40 percent) treated with just Keytruda had recurrence or death, indicating a 44 percent risk reduction"
Statistically, if those in the control group had gotten the treatment, then in expectation 9 of those people wouldn't have had their cancer return or died. It must be exciting to run these sorts of trials with super promising drugs, but also a little bittersweet/dark.
You make a very good point. But the other side of it is that sometimes it goes poorly. The vaccine could have some previously unknown bad reaction with the Keytruda and the numbers get 44% worse instead. In this case it would be better to be in the vaccine group, but that's not guaranteed.
There are affordances for "this works so well and has so few side effects that we are ethically bound to give the control group the drug too." This happened with AZT for HIV.
Resectable cutaneous melanoma metastatic to a lymph node and at high risk of recurrence
Complete resection within 13 weeks prior to the first dose of pembrolizumab
Disease free at study entry (after surgery) with no loco-regional relapse or distant metastasis and no clinical evidence of brain metastases
Has an formalin fixed paraffin embedded (FFPE) tumor sample available suitable for sequencing
Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1
Normal organ and marrow function reported at screening
Key Exclusion Criteria:
Prior malignancy, unless no evidence of that disease for at least 5 years prior to study entry
Prior systemic anti-cancer treatment (except surgery and interferon for thick primary melanomas. Radiotherapy after lymph node dissection is permitted)
Live vaccine within 30 days prior to the first dose of pembrolizumab
Transfusion of blood or administration of colony stimulating factors within 2 weeks of the screening blood sample
Active autoimmune disease
Immunodeficiency, systemic steroid therapy, or any other immunosuppressive therapy within 7 days prior to the first dose of pembrolizumab
Solid organ or allogeneic bone marrow transplant
Pneumonitis or a history of (noninfectious) pneumonitis that required steroids
Prior interstitial lung disease
Clinically significant heart failure
Known history of human immunodeficiency virus (HIV)
Known active hepatitis B or C
Active infection requiring treatment
Ages Eligible for Study
18 Years and older (Adult, Older Adult )
Frequency data =
24 107 | 131
20 50 | 70
--------------------------------------
44 157 201
[### Fisher's exact test ###]
Ho (Null hypothesis) : There is no
association between two classification
of the rows and columns.
Ha (Alternative hypo) : There is an
association between two classification
of the rows and columns.
p = 0.108418 NS (2 tails)
--> Ho was not rejected.
(Reference: Chi square test)
X2 = 2.8036907 (p = 0.094048)
X2Y = 2.2362266 (p = 0.134809)
(Adjusted by Yates Correction)
"Previous data from the trial reported that 107 participants received the mRNA vaccine and Keytruda treatment, while the remaining 50 only received Keytruda. At the two-year follow-up, 24 of the 107 (22 percent) who got the experimental vaccine and Keytruda had recurrence or death, while 20 of 50 (40 percent) treated with just Keytruda had recurrence or death, indicating a 44 percent risk reduction"
Statistically, if those in the control group had gotten the treatment, then in expectation 9 of those people wouldn't have had their cancer return or died. It must be exciting to run these sorts of trials with super promising drugs, but also a little bittersweet/dark.
You make a very good point. But the other side of it is that sometimes it goes poorly. The vaccine could have some previously unknown bad reaction with the Keytruda and the numbers get 44% worse instead. In this case it would be better to be in the vaccine group, but that's not guaranteed.
There are affordances for "this works so well and has so few side effects that we are ethically bound to give the control group the drug too." This happened with AZT for HIV.
40% recurrence seems insanely high after just 2 years.
It makes me wonder what the selection criteria for candidates were
from clinicaltrials.gov:
Eligibility Criteria
Key Inclusion Criteria:
Resectable cutaneous melanoma metastatic to a lymph node and at high risk of recurrence
Complete resection within 13 weeks prior to the first dose of pembrolizumab
Disease free at study entry (after surgery) with no loco-regional relapse or distant metastasis and no clinical evidence of brain metastases
Has an formalin fixed paraffin embedded (FFPE) tumor sample available suitable for sequencing
Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1
Normal organ and marrow function reported at screening
Key Exclusion Criteria:
Prior malignancy, unless no evidence of that disease for at least 5 years prior to study entry
Prior systemic anti-cancer treatment (except surgery and interferon for thick primary melanomas. Radiotherapy after lymph node dissection is permitted)
Live vaccine within 30 days prior to the first dose of pembrolizumab
Transfusion of blood or administration of colony stimulating factors within 2 weeks of the screening blood sample
Active autoimmune disease
Immunodeficiency, systemic steroid therapy, or any other immunosuppressive therapy within 7 days prior to the first dose of pembrolizumab
Solid organ or allogeneic bone marrow transplant
Pneumonitis or a history of (noninfectious) pneumonitis that required steroids
Prior interstitial lung disease
Clinically significant heart failure
Known history of human immunodeficiency virus (HIV)
Known active hepatitis B or C
Active infection requiring treatment
Ages Eligible for Study 18 Years and older (Adult, Older Adult )
Sexes Eligible for Study All
Accepts Healthy Volunteers No
## 12. Fisher exact test ## (2026-1-25, 10:56pm)
Frequency data = 24 107 | 131 20 50 | 70 -------------------------------------- 44 157 201
[### Fisher's exact test ###]
(Reference: Chi square test) X2 = 2.8036907 (p = 0.094048) X2Y = 2.2362266 (p = 0.134809) (Adjusted by Yates Correction)