A Phase 1 Study of Adding Pitavastatin to Venetoclax-Based Therapy in AML and CLL/SLL

Statins (HMG-CoA-reductase inhibitors) are drugs used widely for the treatment of high cholesterol and are generally well-tolerated. There has been increasing interest in repurposing statins for oncology based on the recognition that many cancer cells are “addicted” to the mevalonate biosynthetic pathway (Iannelli et al, 2017; Juarez and Fruman 2021). We have shown that statins increase expression of the pro-apoptotic BCL2 family member PUMA (Lee at al, 2018). We have strong pre-clinical evidence that statins improve responses to the BCL2 inhibitor venetoclax (VEN) in cell line models and ex vivo primary patient specimens from patients with both chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) (Lee et al, 2018). Additionally, retrospective review of patients enrolled into the early clinical trials of VEN in CLL revealed improved responses to VEN (complete remission [CR] and progression-free survival) in the patients who were concurrently on a statin medication (Lee et al, 2018). These retrospective analyses may underestimate the potential of statins for leukemia therapy, as the statin drugs most commonly prescribed for hypercholesterolemia are not pharmacologically optimized for oncology (Abdullah et al., 2018).

We developed a phase 1 study of adding pitavastatin (PIT) to VEN-based therapy in patients with AML and CLL/small lymphocytic lymphoma (SLL) (NCT04512105). AML patients were eligible if receiving induction therapy with azacitidine (AZA) and VEN per standard of care. CLL/SLL patients could receive either VEN with obinutuzumab (O) or rituximab. A 3+3 design was employed. Dose level 1 was PIT 2 mg daily, and dose level 2 (DL2) was 4 mg daily. These doses are consistent with the doses used for the treatment of hypercholesterolemia. Those enrolling at DL2 had a creatinine clearance of 60 mL/min or higher based on the prescribing information for pitavastatin. Patients already on statins for the treatment for hypercholesterolemia were allowed; these patients stopped their prescribed statin for 72 hours prior to initiation of PIT. PIT started after patients completed VEN ramp-up and had been on a stable VEN dose for at least 5 days. Primary objectives were assessing safety and tolerability and determining the recommended phase 2 dose of PIT in combination with VEN-based therapies. Secondary objectives included CR rates. Exploratory objectives included performing BH3 profiling on pretreatment and post-treatment blood samples to assess whether add-on treatment with PIT increases apoptotic priming, as seen in preclinical models (Lee et al, 2018).

14 patients signed informed consent. 6 were deemed ineligible. 2 withdrew consent prior to starting PIT therapy. 6 patients received PIT on study. 2 patients had AML and received AZA+VEN. 2 patients had CLL, and 2 patients had SLL. The CLL/SLL patients all received VEN+O. Grade 1 myalgia was reported in one subject on the 4mg PIT dose. 1 patient experienced a grade 1 increase in AST on the 4mg dose. Another patient had grade 1 elevation in bilirubin and alkaline phosphatase at the 4 mg dose. Grade 3-4 toxicities included leukopenia, neutropenia (1 case of febrile neutropenia, grade 3), anemia, and thrombocytopenia. Cycle 1 was defined as the dose-limiting toxicity (DLT) period, and no hematologic toxicities occurred during the DLT period. 1 patient had grade 3 pancreatitis, but this was felt to be unrelated to therapy or disease (also outside the DLT period). No grade 5 toxicities occurred while on study therapy. Toxicities were overall felt to be similar to patients receiving VEN-based therapy in standard clinical practice. All evaluable patients (n=5) achieved clinical CR. 1 patient with SLL is awaiting re-staging at the time of this abstract.

Correlative studies are ongoing. In 2 patient peripheral blood samples analyzed, the % blasts (for an AML sample) and % CD5+ B-cells (for a CLL sample) were reduced 24 hours after PIT dosing compared to prior to any treatment and before PIT/after VEN ramp-up.

Based on the tolerability of PIT and encouraging clinical outcomes, a phase 2 study is being planned to better assess the efficacy of adding PIT to VEN-based therapies in AML and CLL/SLL.