Updated Results of a Phase I Study of RAD001 In Combination with Lenalidomide In Patients with Relapsed or Refractory Multiple Myeloma with Pharmacodynamic and Pharmacokinetic Analysis

Lenalidomide (Revlimid^®, Len) plus dexamethasone (Dex) is approved for the treatment of relapsed or refractory multiple myeloma (MM) patients following ≥1 prior therapy. RAD001, an mTOR inhibitor has been studied as a single agent in MM, and although well tolerated, did not have single agent activity. Informed by our previous studies demonstrating synergistic anti-MM activity of mTOR inhibitors when combined with Len, we studied this combination to evaluate its safety and activity as a non-steroid containing oral regimen in advanced MM.

Patients with relapsed and refractory MM were assigned to Len and RAD001 to be taken for 21 days of a 28 day cycle (NCT00729638) in a standard 3+3 design. Patients were allowed to continue therapy until disease progression or unacceptable toxicity and were required to receive concomitant anti-thrombotic (aspirin 81 or 325 mg/day) therapy. Peripheral blood and bone marrow samples were collected before and after treatment for pharmacokinetic and pharmacodynamic studies.

Twenty-eight patients were registered on the trial between December 2008-December 2009. Two patients were inevaluable because of either rapidly progressive disease or failure to meet eligibility criteria on day 1. Data on 26 patients are therefore available. Pts had received a median of 4 prior lines of treatment.14 pts had received Len previously of which 11 pts had relapsed disease and 3 pts had relapsed/refractory disease. Both cohort 1 (Len: 10mg/day and RAD001: 5mg/every other day ×21 days of 28 day cycle) and 2 (Len: 15mg/day and RAD001: 5mg daily ×21 days of 28 day cycle) required expansion because of grade 3 neutropenia and grade 4 thrombocytopenia. Dose limiting toxicities included grade 4 neutropenia and thrombocytopenia in 2/3 patients in cohort 3 (Len: 20mg and RAD001: 5 mg × 21 days). The maximum tolerated dose (MTD) was therefore declared at 15 mg of len and 5mg of RAD001 for 21 days with a 7 day rest period. Most common (≥10%) Grade 1/2 events included nausea, fatigue, dyspnea, diarrhea, constipation, neuropathy and muscle cramps, all of which proved manageable with supportive care. One patient developed RAD related non-infectious pneumonitis requiring therapy discontinuation. Grade 3/4 adverse events (≥ 5%) included thrombocytopenia (11%) and neutropenia (22%). Nineteen patients completed 2 cycles and were evaluable for response. Median follow up is currently 8.7 months and median PFS is 4.3 months, with 12 patients receiving treatment at MTD. Overall response rate was 68% (13/19) (90% CI: [30-76%]) including CR(1) PR(2), MR(8) and SD(2). Four patients continue on the combination at 13, 14, 15 and 17 months respectively.

Pharmacokinetic and pharmacodynamic data including immunohistochemistry for phosphorylated AKT, cytokine profiles, T cell subsets and transcription profile on MM cell pre and post treatment as well as correlation of response with pharmacodynamic studies will be presented.

The combination of Len plus RAD001 is a well tolerated regimen with predictable hematological toxicities. Promising responses were noted in this heavily pretreated patient population with advanced MM. This combination thus provides an oral steroid free combination treatment strategy which warrants future evaluation in phase II studies.

Richardson:Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees. Ghobrial:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millennium Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees. Adams:Novartis: Employment. Makrides:Celgene: Employment. Munshi:Millennium Pharmaceuticals: Honoraria, Speakers Bureau. Anderson:Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Raje:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Astra Zeneca: Research Funding; Acetylon: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Lenalidomide and RAD 001 for treatment of relapsed and refractory multiple myeloma.