Phase I/II results of ceralasertib as monotherapy or in combination with acalabrutinib in high-risk relapsed/refractory chronic lymphocytic leukemia.

Background: Patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL) have limited treatment options. Ceralasertib, a selective ataxia telangiectasia and Rad-3-related protein (ATR) inhibitor, demonstrated synergistic preclinical activity with a Bruton tyrosine kinase (BTK) inhibitor in TP53- and ATM-defective CLL cells. Acalabrutinib is a selective BTK inhibitor approved for treatment of CLL. Objectives: To evaluate ceralasertib ± acalabrutinib in R/R CLL. Design: Nonrandomized, open-label phase I/II study. Methods: In arm A, patients received ceralasertib monotherapy 160 mg twice daily (BID) continuously (cohort 1) or 2 weeks on/2 weeks off (cohort 2). In arm B, patients received acalabrutinib 100 mg BID continuously (cycle 1), followed by combination treatment with ceralasertib 160 mg BID 1 week on/3 weeks off from cycle 2. Co-primary objectives were safety and pharmacokinetics. Efficacy was a secondary objective. Results: Eleven patients were treated [arm A, n = 8 (cohort 1, n = 5; cohort 2, n = 3); arm B, n = 3 (acalabrutinib plus ceralasertib, n = 2; acalabrutinib only, n = 1)]. Median duration of exposure was 3.5 and 7.2 months for ceralasertib in arms A and B, respectively, and 15.9 months for acalabrutinib in arm B. Most common grade ⩾3 treatment-emergent adverse events (TEAEs) in arm A were anemia (75%) and thrombocytopenia (63%), with four dose-limiting toxicities (DLTs) of grade 4 thrombocytopenia. No grade ⩾3 TEAEs or DLTs occurred in arm B. Ceralasertib plasma concentrations were similar when administered as monotherapy or in combination. At median follow-up of 15.1 months in arm A, no responses were observed, median progression-free survival (PFS) was 3.8 months, and median overall survival (OS) was 16.9 months. At median follow-up of 17.2 months in arm B, overall response rate was 100%, and median PFS and OS were not reached. Conclusion: Ceralasertib alone showed limited clinical benefit. Acalabrutinib plus ceralasertib was tolerable with preliminary activity in patients with R/R CLL, though findings are inconclusive due to small sample size. Registration: NCT03328273.

No clinically relevant drug-drug interactions when dalcetrapib is co-administered with atorvastatin.

OBJECTIVES: Dalcetrapib, which targets cholesteryl ester transfer protein, is in clinical development for prevention of cardiovascular events and is likely to be used concomitantly with statins. Two studies investigated co-administration of dalcetrapib with atorvastatin and any effects of the timing of atorvastatin on the pharmacokinetics of dalcetrapib. RESEARCH DESIGN AND METHODS: Two crossover studies were performed in healthy subjects: a two-period study of dalcetrapib 900 mg concurrently with atorvastatin (concurrent dosing study) and a three-period study of dalcetrapib 600 mg (dose chosen for Phase III) with atorvastatin concurrently or serially 4 h after dalcetrapib (interval dosing study). MAIN OUTCOME MEASURES: The primary pharmacokinetic end points were AUC(0 - 24) and C(max); lipid effects and tolerability were secondary end points. RESULTS: In the concurrent study (n = 26), co-administration reduced dalcetrapib AUC(0 - 24) and C(max) and caused small changes in AUC(0 - 24) and C(max) of atorvastatin and its active metabolites. In the interval study (n = 52), serial and concurrent co-administration of atorvastatin resulted in similar reductions in dalcetrapib exposure that were comparable to those observed in the concurrent dosing study. Co-administration did not decrease the efficacy of dalcetrapib or atorvastatin and was generally well tolerated. CONCLUSIONS: These results indicate no clinically relevant interactions for co-administration of dalcetrapib with atorvastatin.

Coadministration of dalcetrapib with pravastatin, rosuvastatin, or simvastatin: no clinically relevant drug-drug interactions.

Dalcetrapib targets cholesteryl ester transfer protein and increases high-density lipoprotein cholesterol (HDL-C) levels. It is in clinical development for the prevention of cardiovascular events and will likely be used in combination with standard of care, including statins. Three crossover studies in healthy males investigated the pharmacokinetic drug-drug interaction potential of 900 mg dalcetrapib and statins: two 3-period studies (dalcetrapib plus pravastatin or rosuvastatin) and a 2-period study (dalcetrapib plus simvastatin). Effect on lipids and safety were secondary end points. The 900 mg dose investigated is higher than the 600 mg dose currently being investigated in Phase III. Coadministration of dalcetrapib with pravastatin, rosuvastatin, or simvastatin was not associated with significant increases in statin exposure except for a 26% increase in rosuvastatin C(max) (90% CI 1.088 to 1.468) but not AUC(0-24) (90% CI 0.931 to 1.085). Dalcetrapib AUC(0-24) and C(max) were not significantly altered by coadministration with pravastatin, and were significantly lower when dalcetrapib was coadministered with rosuvastatin or simvastatin compared with dalcetrapib alone. The HDL-C increase with dalcetrapib was not compromised by coadministration with statins, and reduction in low-density lipoprotein cholesterol with dalcetrapib coadministered with statins was greater than with statins alone. Dalcetrapib alone and coadministered with statins was generally well tolerated.