Dual targeting of MCL1 and NOXA as effective strategy for treatment of mantle cell lymphoma

Imbalances in the composition of BCL2 family proteins contribute to tumourigenesis and therapy resistance of mantle cell lymphoma (MCL), making these proteins attractive therapy targets. We studied the efficiency of dual targeting the NOXA/MCL1 axis by combining fatty acid synthase inhibitors (NOXA stabilization) with the CDK inhibitor Dinaciclib (MCL1 reduction). This combination synergistically induced apoptosis in cell lines and primary MCL cells and led to almost complete inhibition of tumour progression in a mouse model. Apoptosis was NOXA‐dependent and correlated with the NOXA/MCL1 ratio, highlighting the importance of the NOXA/MCL1 balance for effective cell death induction in MCL.     

Randomized phase 2 study of the cyclin-dependent kinase inhibitor dinaciclib (MK-7965) versus erlotinib in patients with non-small cell lung cancer

Objectives

Dinaciclib (MK-7965, formerly SCH 727965), a novel, small-molecule inhibitor of cyclin-dependent kinases, has been shown to induce apoptosis in preclinical studies of human tumor cell lines, including non-small cell lung cancer (NSCLC) cells. Erlotinib, an epidermal growth factor receptor inhibitor, is approved for the treatment of advanced NSCLC as second- or third-line therapy. This phase 2, randomized, multicenter, open-label study compared dinaciclib with erlotinib in patients with previously treated NSCLC.

Materials and methods

The study was comprised of 2 parts: in part 1, patients were randomized to either intravenous (IV) dinaciclib (50 mg/m²) or oral erlotinib (150 mg) using an adaptive Bayesian design that adjusted the randomization ratio in favor of the more active arm, and in part 2, patients who had progressed on erlotinib were permitted to cross over to receive dinaciclib at the same dosage as in part 1. Patients were followed until disease progression or death, initiation of nonstudy cancer treatment, discontinuation, or withdrawal of consent. The primary efficacy end point was time-to-progression (TTP) in part 1 and objective response rate (ORR) in part 2.

Results

Based on Kaplan–Meier estimates, the median TTP was 1.49 months (95% confidence interval [CI]: 1.31, 2.63) following initial treatment with dinaciclib, compared with 1.58 months (95% CI: 1.38, 2.83) with erlotinib. No objective responses were observed following initial treatment with dinaciclib. Common severe (grade 3 or 4) drug-related adverse effects included neutropenia, leukopenia, vomiting, and diarrhea.

Conclusions

Dinaciclib, administered IV, was well tolerated at the 50 mg/m² dose, but does not have activity as monotherapy in previously treated NSCLC. Evaluation of dinaciclib in combination with other agents for other indications including breast cancer and multiple myeloma is in progress.