# Monte Carlo / bootstrapping to generate a Kaplan Meier curve

I have 4 survival datasets from 4 different trials examining 2 different drug classes independently.

I would like to model the likely survival curve resulting from a pooled selection of either drug class, preferably with an ability to dictate weights for each drug class type in the final model (e.g., 50% of patients come from drug class 1, 50% of patients come from drug class 2)

What would be the best way to do this in R?

I've looked at censboot, but that seems more inline with bootsrapping a specific statistic from the data.

My end goal is to use this modeled arm to predict cut-offs for a treatment effect of an add-on therapy.

Truly appreciate any input / examples.

• Could you elaborate on the end goal? I don't think you could use bootstrap to estimate the entire survival curve. How about using bootstrap to estimate the survival probability at specific time points. (example, each month or so). – dietervdf Aug 1 '18 at 22:38
• I ended up using sample to create a new dataframe from existing individual patient dataframes and reconstructed a KM curve from that. The goal to construct a KM curve over a 36 month period, which I believe this straightforward approach achieved adequately. Thanks for the questions though! – wingsoficarus116 Aug 2 '18 at 16:25

n_control <- 10000

perc_ambri <- 0.10
perc_maci <- 0.40
perc_maci_control <- 0.25

ambri_sample = ambri_mono[sample(nrow(ambri_mono),
size = perc_ambri * n_control,
replace=TRUE,
prob=NULL),]

replace=TRUE,
prob=NULL),]

maci_sample = maci_mono[sample(nrow(maci_mono),
size = perc_maci * n_control,
replace=TRUE,
prob=NULL),]

maci_control_sample = maci_control_mono[sample(nrow(maci_control_mono),
size = perc_maci_control * n_control,
replace=TRUE,
prob=NULL),]

control_arm = bind_rows(list(ambri_sample, tada_sample, maci_sample, maci_control_sample))

control_arm\$arm <- NULL

# this last bit was done so given that I wanted a ~350pt dataset
#but wanted to reduce variability in the overall result for repeatability
control_arm = control_arm[sample(nrow(control_arm),
size = 696/2,
replace=TRUE,
prob=NULL),]