Pacritinib in Combination With a BTK Inhibitor for the Treatment of Patients With Relapsed or Refractory Mantle Cell Lymphoma

This study is testing pacritinib — a drug that blocks certain growth signals in cancer cells — combined with a BTK inhibitor (another targeted cancer drug) in patients with mantle cell lymphoma (MCL) that has come back or stopped responding to previous treatment. **You may be eligible if...** - You are 18 or older with a confirmed diagnosis of mantle cell lymphoma - Your lymphoma has relapsed (come back) or is refractory (no longer responding) to prior treatment - Your general health score (ECOG) is 2 or lower - You are willing to provide a tumor tissue sample **You may NOT be eligible if...** - Your heart function is significantly impaired - You have active bleeding problems or are on certain blood thinners - You have had severe side effects from prior BTK inhibitor treatment that would make re-treatment unsafe - You have uncontrolled infections or other serious conditions Talk to your doctor to see if this trial is right for you.