When the effect of treatment may vary by individual, precision medicine can be improved by identifying patient covariates to predict the effect at the individual level. One may impose a working model in order to smooth (or summarize) the conditional effect rather than estimate the effect separately for all possible patient subgroups. When working with observational data one must also adjust for all potential confounders of the treatment-outcome relationship, which can be accomplished with propensity score and/or outcome regression modeling. Due to large data requirements, investigators may be interested in using the individual patient data from multiple studies. Our data arise from a systematic review of observational studies contrasting different treatment regimens for patients with multidrug-resistant tuberculosis, where multiple antibiotics are taken concurrently over a long period to cure the infection. We develop a targeted maximum likelihood estimator (TMLE) to fit a marginal structural model representing the treatment effect model in the individual patient data network meta-analytic setting when, for instance, any given treatment may not be observed in all studies.