Clarithromycin (Biaxin)-Lenalidomide-Low-Dose Dexamethasone (BiRd) Versus Lenalidomide-Low-Dose Dexamethasone (Rd) as Initial Therapy for Newly Diagnosed Multiple Myeloma.

In newly diagnosed multiple myeloma (MM), the combination of lenalidomide plus high-dose dexamethasone (RD) is superior to high-dose dexamethasone (Zonder JA et al, Blood 2007;110:77). Preliminary results show that lenalidomide plus low-dose dexamethasone (Rd) has better 2-year overall survival (OS) compared with RD (Rajkumar SV et al, J Clin Oncol 2008;26:8504). The addition of clarithromycin (Biaxin) to lenalidomide and low-dose dexamethasone (BiRd) has been investigated in a phase II study, demonstrating a high response rate and 2-year OS (Niesvizky R at al, Blood 2008;111:1101-1109). However, the additive value of clarithromycin is not known. No randomized trials have compared Rd versus BiRd, none are planned. The objective of this case–matched study was to compare the efficacy and the toxicity of BiRd vs Rd as initial therapy for newly diagnosed MM.

Data from 72 newly diagnosed MM patients treated at the New York Presbyterian Hospital–Cornell Medical Center, from December 2004 to December 2006, with BiRD, were analyzed. For comparison, an equal number of pair mates were selected among newly diagnosed patients seen at the Mayo Clinic who received Rd, from March 2005 to December 2008. Case matching was performed with respect to age, gender, and transplant status. Patients treated with BiRd received oral lenalidomide (25 mg/day, days 3-21 of cycle 1; days 1-21 of subsequent cycles); dexamethasone (40 mg days 1, 2, 3, 8, 15, 22 of cycle 1; days 1, 8, 15, and 22 of each subsequent cycle); clarithromycin (500 mg twice daily, from day 2 of cycle 1). Patients treated with Rd received oral lenalidomide (25 mg/day, days 1-21) plus low-dose dexamethasone (40 mg days 1, 8, 15, 22). In both groups patients were allowed to discontinue treatment to pursue transplant, but treatment until progression, relapse or unacceptable toxicity was permitted at the physician's discretion. Outcome was analyzed on an intention-to-treat basis. The Chi-square or the rank sum tests were used to compare variables. Time-to-event analysis was performed using the Kaplan-Meier method; comparisons were determined by the log-rank test and the Cox proportional hazards model.

Median duration of treatment was 11.8 months in the BiRd group vs 6 months in the Rd group. On intention-to-treat analysis, complete response was significantly higher with BiRd compared to Rd (45.8% vs 13.9%, respectively, p<0.001); similarly very good partial response (VGPR) or better was higher with BiRd (73.6% vs 33.3%, p<0.001). Rates of VGPR or better, after 6 months and 1 year of therapy, were significantly higher in BiRd patients. Both time-to-progression (TTP) (median 48.3 months vs 27.5 months; HR 0.51; 95% CI 0.25-1.06; p=0.071) and PFS (median 48.3 months vs 27.5 months, HR 0.50; 95% CI 0.25-0.98; p=0.044) were higher with BiRd. Median time to next treatment (TTNT) was not reached in BiRd group compared to 29.9 months in Rd patients (HR 0.37 95% CI 0.20-0.66, p<0.001). There was a trend toward better OS with BiRd, (3-year OS: 89.7% vs 73.0%), but the difference was not statistically significant (HR 0.48; 95% CI 0.17-1.37; p=0.170). Thirty-two patients in each group received transplant; median time to transplant was longer in BiRd group (13.5 vs 5.9 months). Results of survival, for patients who received transplant and patients who did not, were similar to those of the total population. On subset analysis, among patients presenting with International Staging System (ISS) stage I/II at diagnosis, TTP, PFS and TTNT were significantly longer in BiRd patients; no significant differences were found among patients with ISS stage III. Main grade 3-4 toxicities of BiRd were hematological, in particular thrombocytopenia (23.6% vs 8.3%, p=0.012); rate of neutropenia was similar between the 2 groups (19.4% vs 16.7%, p=0.665). Infections (16.7% vs 9.7%, p=0.218) and dermatological toxicity (12.5% vs 4.2%, p=0.129) were higher in patients who received Rd. Rate of venous thromboembolism was similar in the 2 groups (9.7% vs 12.5%, respectively in Rd and BiRd patients, p=0.596).

Results of this case-control analysis suggest superiority of BiRd in terms of response rate and survival, compared with Rd, and suggest that there may be a significant additive value when clarithromycin is added to Rd. These data indicate the need for randomized prospective phase III studies to evaluate BiRd versus Rd in the treatment of MM.

Off Label Use: research drug in combination to standard of care. Kumar:celgene: Research Funding; millenium: Research Funding; bayer: Research Funding; novartis: Research Funding; genzyme: Research Funding. Mark:celgene: Research Funding. Dispenzieri:celgene: Research Funding. Gertz:celgene: Honoraria; genzime: Honoraria; millenium: Honoraria; amgen: Honoraria. Leonard:celgene: Consultancy. Lacy:celgene: Research Funding. Witzig:celgene: Research Funding. Fonseca:medtronic: Consultancy; genzyme: Consultancy; celgene: Consultancy; amgen: Consultancy; BMS: Consultancy; otsuka: Consultancy. Greipp:celgene: Research Funding. Niesvizky:celgene: Research Funding, Speakers Bureau; Millenium: Research Funding, Speakers Bureau; Proteolix: Research Funding, data monitoring committee.