Final Phase I Results of Perifosine In Combination with Lenalidomide and Dexamethasone In Patients with Relapsed or Refractory Multiple Myeloma (MM)

Perifosine (Peri) a novel, oral signal transduction modulator with multiple effects including inhibition of Akt and activation of JNK, has demonstrated clinical activity when combined with dexamethasone (Dex) in patients (pts) with relapsed/refractory MM (ASH 2007 #1164). Lenalidomide (Revlimid , Rev) a novel, oral immunomodulatory drug has activity against MM when combined with Dex. We previously reported encouraging safety data and observed clinical activity of the oral triplet combination (ASH 2008 # 3691). We now report the final phase I results of this study which aimed to determine the MTD and to evaluate activity of Peri + Rev + Dex, as an oral combination in pts with relapsed or refractory MM.

Four cohorts ( 6 pts each) were planned, dosing Peri at 50 or 100mg (daily), Rev 15 or 25mg (d 1–21) and Dex 20mg (d 1–4, 9–12 and 17–20 for 4 cycles, then 20 mg d 1–4) in 28-d cycles. To limit dex-related toxicities, the protocol was amended to use weekly dex (40 mg), applying to cohorts 3, 4, and the MTD cohort. Toxicity was assessed using NCI CTCAE v3.0; DLT was defined as grade (G) 3 non-hematologic toxicity, G4 neutropenia for 5 d and/or neutropenic fever, or platelets <25,000/mm³ on >1 occasion despite transfusion. Response was assessed by modified EBMT criteria. Pts had to have received at least 1 prior therapy and no more than 4. Pts refractory to Rev/Dex were excluded.

32 pts (17M/15F, median age 64 y, range 37 – 79) were enrolled; 6 pts in cohort 1 (Peri 50mg, Rev 15mg, Dex 20mg); 6 pts in cohort 2 (Peri 50mg, Rev 25mg, Dex 20mg); 8 pts in cohort 3 (Peri 100mg, Rev 15mg, Dex 40mg/wk); 6 pts in cohort 4 (Peri 100mg, Rev 25mg, Dex 40mg/wk) and 6 pts at MTD (Cohort 4). Median prior lines of treatment was 2 (range 1–4) with a median PS of 1. Relapsed (53%), Refractory to last therapy prior to study entry (47%). Prior therapy included dex (94%), thalidomide (75%), bortezomib (44%), and stem cell transplant (72%). Two pts (6%) were previously treated with Rev. 63% (15/24) of the prior thalidomide + dex (Thal/Dex) treated pts had progressed on a Thal/Dex regimen while 43% (6/14) of the prior bortezomib (Vel) treated pts had progressed on a prior Vel based regimen. Two pts did not complete one full cycle (non-compliance and adverse event not related to study drugs – both in cohort 3) and were not included in the efficacy analysis. 31/32 pts were evaluable for safety (non-compliant patient never took study drug and was excluded). The most common grade 1/2 events (any causality) included fatigue (48%), diarrhea (45%), upper respiratory infection (35%), nausea (32%) and hyperglycemia (32%). Grade 3/4 events > 10% included neutropenia (26%); hypophosphatemia (23%); thrombocytopenia (16%) and leucopenia (13%). There was one reported DLT in cohort 3 (Nausea). No grade 3/4 events of peripheral neuropathy or DVT were reported. Rev dose was reduced in 11 pts, Peri reduced in 9 pts and Dex reduced in 7 pts: 30 pts are evaluable for response, with best response as follows:

Median progression-free survival (PFS) for all pts was 10.8 mos (CI: 4.6, 27.7) and 7 pts have not progressed. The median overall survival (OS) was 30.6 mos (CI: 16.7, NR) with 15/30 pts still alive. Of the 8 thalidomide naïve pts, 4 have progressed with a median projected PFS of 30 mos and all 8 pts remain alive (range 28 – 43 mos).

Pts have tolerated Peri + Rev + Dex well with manageable toxicity, and with promising clinical activity demonstrated by an ORR (≥ PR) of 50%, an extended PFS and OS. Given that most pts were exposed to Thal/Dex with more than half refractory to a prior Thal/Dex regimen, the encouraging response rates and survival appear to suggest benefit with the addition of perifosine to Rev/Dex. This data thus warrants further study, including a potential randomized trial to confirm the activity of perifosine added to Rev/Dex. A randomized phase III trial of Peri/Vel/Dex vs. Vel/Dex is underway for previously Vel exposed MM patients.

Jakubowiak:Millennium, Celgene, Bristol-Myers Squibb, Johnson & Johnson Ortho-Centocor: Honoraria; Millennium, Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Millennium, Celgene, Centocor-Ortho Biotech: Speakers Bureau. Off Label Use: Perifosine in combination with Lenalidomide and Dexamethasone. 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. Zimmerman:Millennium, Celgene: Speakers Bureau. Alsina:Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Ortho Biotech: Research Funding. Kaufman:Celgene, Millenium: Consultancy; Celgene, Merck: Research Funding. Sportelli:Keryx Biopharmaceuticals: Employment, Equity Ownership. Gardner:Keryx Biopharmaceuticals: Employment, Equity Ownership. Anderson:Celgene: Consultancy, Honoraria, Speakers Bureau; Millennium: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau.