brms

It is available from CRAN, so it can be installed with install.packages(). Here is a documentation example,

  library(brms)
# Survival regression modeling the time between the first
# and second recurrence of an infection in kidney patients.
  fit3 <- brm(time | cens(censored) ~ age * sex + disease + (1|patient),
              data = kidney, family = lognormal())
  summary(fit3)
  plot(fit3, ask = FALSE)
  plot(conditional_effects(fit3), ask = FALSE)
  fit3cox <- brm(time | cens(censored) ~ age * sex + disease + (1|patient),
                 data = kidney, family = family('cox'))
  summary(fit3cox)
  plot(fit3cox, ask = FALSE)
 

In case of compilng error, it is necessary to use the developmental version of rstan (2.21.3 at the time of writing), see below.