Bortezomib in Combination with Pegylated Liposomal Doxorubicin and Thalidomide (VDT), An Effective Steroid Independent Regimen for Previously Untreated Multiple Myeloma Patients: Final Result of a Phase II Study.

Steroids have been an important component of multiple myeloma (MM) therapeutics. High doses steroids as used in MM are associated with significant toxicity and morbidity. Development of steroid independent or steroid-lite regimens remains an important area of investigation in MM. Orlowski et al combined Doxil (D) with bortezomib (V) and showed enhanced anti-myeloma activity. In a phase II study in relapsed refractory MM patients, we observed further improvement in clinical efficacy with addition of thalidomide (T) to VD combination (VDT regimen). Encouraged by high response rates of this steroid sparing novel combination we investigated VDT regimen in treatment naïve MM patients. Final results of this phase II trial are reported here.

Patients with previously untreated MM were eligible for this phase II trial. VDT regimen (V 1.3mg/m² on days 1, 4,15,18; D 20mg/m² on days 1,15 and T 200 mg daily continuously) given on a 4-week cycle for a maximum of 8 cycles. Acyclovir (400 mg BID) and weight adjusted low-dose warfarin (1 or 2mg for absolute body weight <70kg or ≥70kg, respectively) was given for prophylaxis of herpes zoster and deep vein thrombosis (DVT), respectively. Response was assessed using the modified Blade criteria.

Forty patients (26 males, 14 females; median age 60.5, range 40-80 yrs) were enrolled on this study. Among these 58%(n=23) had stage III (Durie-Salmon) disease with a median b2 microglobulin of 3.7 (range 1.6-16.5 mg/L) and median LDH of 443 (range 152-129 IU/L). Thirty-nine patients are eligible for response evaluation (1 too early for assessment). Overall response rate (CR/nCR+PR) was 79.4% (n=31) with 38% (n=15) patients achieving CR/nCR. The median progression free (PFS) and overall survival (OS) has not been reached. At 1 year the PFS and OS is 81% and 97%, respectively (1 patient died from disease progression to leukemic phase). Toxicity: Neutropenia was the most significant hematological toxicity with grade 3 and 4 neutropenia observed in 22.5% and 2.5% of the patients, respectively. Only 1 (2.2%) patient had febrile neutropenia. Clinically significant neuropathy (grade ≥2) was seen in 20% while grade ≥2 palmer planter erythrodysesthesia was seen in 15% (n=6) of the patients. Other grade 3 non-hematological toxicities included pneumonia (20%), pleural effusion (10%), pulmonary embolism (2%), DVT (2%), congestive heart failure (5%) and interstitial pneumonitis (2%).

Although effective, steroid based treatment regimen can be associated with significant toxicity especially among patients with concurrent co morbid conditions such as hypertension and diabetes mellitus. Furthermore, recent investigations demonstrate that decreasing steroid doses may actually improve PFS and OS despite a comparatively low initial ORR. In this clinical trial we hypothesized that rational combination of novel myeloma agents may actually preclude the need to rely on high-dose steroids without significantly compromising ORR. Consistent with our expectations, the VDT regimen has ORR comparable to some of the steroid-inclusive triple drug combinations. The toxicity profile of this combination was acceptable and the regimen was well tolerated. Thus we note that VDT is an effective and well tolerated steroid-independent induction regimen for MM patients.

Off Label Use: A Phase II study of a novel combination in newly diagnosed myeloma patients. Miller:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Czuczman:Centocor Ortho Biotech: Research Funding. Sood:Celgene: Stock. Chanan-Khan:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immunogen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.