One-way sensitivity analyses. (A) Tornado diagram of 1-way sensitivity analysis on multiple model parameters. Parameter values corresponding to the low and high ICER are highlighted. (B) Sensitivity to the cost of ibrutinib at initiation of therapy. Values on labeled points represent monthly costs of ibrutinib to reach the corresponding willingness-to-pay (WTP) thresholds. Notably, to be considered cost-effective for a health care system that is willing to pay $150 000 per QALY, the cost of ibrutinib would need to be less than $6800 per month when compared to the comparator, which is likely to be less effective than combination chemoimmunotherapy in the population analyzed. Supplemental Table 11 contains costs of ibrutinib that reach the same WTP thresholds presented above when examining more effective comparators. (C) A sensitivity analysis on a hazard ratio (HR) applied only to the progression rate of the comparator drug, holding all other variables constant. The PFS and OS curves are plotted, with the corresponding ICERs labeled on the right. The base case ICER of $189 000 is highlighted along with increasing ICERs as the efficacy of the comparator is improved, which illustrates worsened performance by ibrutinib from a cost-effectiveness perspective. GChl, obinutuzumab plus chlorambucil (survival curves from Goede et al¹⁴ ).