Supplementary Material for: Intake of Proton Pump Inhibitors is Associated with a Shorter Time To First Treatment in early-stage Chronic Lymphocytic Leukemia.

Proton pump inhibitors (PPIs) are one of the most widely used drugs worldwide(1). The use of PPI has become a common practice, and are overprescribed for all patients with cancer including patients with hematological malignancies.
In the current study, we aimed to explore retrospectively the effect of PPI, on time to first treatment (TTFT) in a large cohort of patients with Chronic lymphocytic leukemia who were under watch and wait approach.
Our cohort included 3,474 patients with CLL who are treatment-naïve, and the median follow-up was 1745 days (602-3700). 1061 patients (30.5%) received a PPI agent, for a minimum of 3 months during the watch-and-wait period.
The intake of PPI was found to be associated with a shorter TTFT: among PPI users, the ten years treatment free ratio is 79.2%, while among non PPI users it is 90.6%.
In conclusion, routine use of PPI in CLL patients may negative impact their clinical course. Biology of this primary observation require further investigation.