Phase I study of the oral mammalian target of rapamycin inhibitor everolimus (RAD001) in Japanese patients with relapsed or refractory non-Hodgkin lymphoma

Phase I study was conducted to evaluate the safety, pharmacokinetics (PK) and efficacy of the oral mammalian target of rapamycin inhibitor, everolimus (RAD001), in patients with relapsed or refractory non-Hodgkin lymphoma (NHL). Patients received everolimus 5 or 10 mg orally once daily. Dose escalation was based on the safety assessment and the probability of dose-limiting toxicities (DLTs) using a Bayesian logistic model. DLTs were evaluated in six patients at each dose level during the initial 28 days of study treatment. A total of 13 patients were enrolled; 5 mg (seven) and 10 mg (six). No DLTs were observed at either dose level. Frequently observed potentially drug-related adverse events included leukopenia (8/13), thrombocytopenia (8/13), elevated hepatic transaminase (9/13), stomatitis (7/13), anemia (6/13), and nasopharyngitis (6/13). All adverse events were reversible. Non-infectious pneumonitis (grade 1) in one patient resolved following discontinuation of everolimus. Two patients with diffuse large B cell lymphoma and two patients with follicular lymphomas achieved objective responses with an overall response rate of 31% (4/13). The pharmacokinetic profiles were not different from those in non-Japanese patients. Everolimus was well tolerated at doses up to 10 mg/day and showed potential efficacy in relapsed or refractory NHL, warranting further investigation.

Targeted therapy in haematological malignancies

The recent and rapid development of molecularly targeted therapy is best illustrated by advances in the management of haematological malignancy. In myeloid diseases we have seen dramatic improvements in the overall survival and quality of life for patients with chronic myeloid leukaemia treated with ABL and Src/ABL kinase inhibitors and we are poised to discover whether JAK2 inhibitors may offer similar benefit in myeloproliferative diseases. For acute myeloid leukaemia, the introduction of ATRA and myelotarg have had major impacts on the design of therapy regimens and many novel targeted agents, including farnesyl transferase, FLT3 and histone deacetylase inhibitors, are now in clinical trial. In lymphoid malignancies the highlight has been the introduction of rituximab, with significant improvements in the management of non-Hodgkin lymphoma and chronic lymphocytic leukaemia. The last 10 years has experienced a rapidly expanding interest and acceptance that leukaemic stem cells, including an improved ability to target them, may hold the key to improved response and reduced relapse rates across both myeloid and lymphoid disease. We now eagerly anticipate an era in which a wealth of preclinical discoveries are progressed to the clinic.

The future of small molecule inhibitors in lymphoma

For the many patients with lymphoma that has relapsed after and/or has become refractory to existing treatments, the development of novel therapeutics is imperative. Investigation into intracellular processes that are dysregulated during lymphomagenesis has uncovered several new potential targets for anticancer agents. Although monoclonal antibodies and other immunotherapeutics have led to dramatic advances in the treatment of patients with lymphoma, the parallel development of small molecule inhibitors has been equally exciting. These agents, whose small size allows direct entry into tumor cells, can target distinct proteins or complexes, thereby disrupting molecular processes on which neoplastic cells depend for survival and growth. This review surveys the published literature on many of these new targeted molecules, focusing on some of the most promising agents for which phase 2 data currently exist. It also explores the potential for incorporating these agents into broader multidrug regimens.

A phase 2 study with a daily regimen of the oral mTOR inhibitor RAD001 (everolimus) in patients with metastatic clear cell renal cell cancer

BACKGROUND

Everolimus, an oral mammalian target of rapamycin (mTOR) inhibitor, affects tumor growth by blocking growth factor stimulation, arresting cell cycle progression, and inhibiting angiogenesis. mTOR inhibitors and agents with primarily antiangiogenic activity have been shown to have efficacy in renal cell cancer (RCC). This phase 2 study assessed the efficacy of daily oral dosing with everolimus in patients with RCC.

METHODS

Patients had confirmed predominantly clear cell RCC; had received <or=1 prior therapy; and had progressive, measurable metastatic disease. Everolimus was given at a dose of 10 mg daily orally without interruption (28-day cycle), with dose modifications for toxicity (graded according to National Cancer Institute Common Toxicity Criteria, version 3.0). Patients were evaluated every 2 cycles (8 weeks) using Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

Of 41 enrolled patients, 39 were treated and evaluable for safety, 37 of whom were evaluable for response (2 patients withdrew after the first week of therapy). Approximately 78% of the patients were male, the median age was 60 years, 93% had a Zubrod performance status of 0 to 1, and 83% had received prior therapy. The median progression-free survival (PFS) was 11.2 months and the median overall survival was 22.1 months. Partial responses were observed in 5 (14%) patients, stable disease lasting >or=3 months was reported in 27 (73%) patients, and stable disease lasting >or=6 months was reported in 21 (57%) patients. Nausea (38% of patients), anorexia (38% of patients), diarrhea (31% of patients), stomatitis (31% of patients), pneumonitis (31% of patients), and rash (26% of patients) were common. Grade 3 of 4 adverse events included pneumonitis (18% of patients); transaminase elevations (10% of patients); thrombocytopenia, hyperglycemia, and alkaline phosphatase elevations (8% each of patients); and hyperlipidemia (5% of patients).

CONCLUSIONS

In the current study, everolimus demonstrated encouraging antitumor activity against metastatic RCC as indicated by a PFS >or= 6 months for approximately 70% of patients.