PAD Induction Therapy Followed by Autologous Peripheral Blood Stem Cell Transplant (APBSCT) as Upfront Treatment for Myeloma (MM) in Chinese Patients.

The anti-myeloma effect of bortezomib, used as a single agent or in combination chemotherapy, is well recognized in various clinical studies. The aim of this study is to determine the feasibility of using the PAD combination (bortezomib, doxorubicin and dexamethasone) as upfront treatment in Chinese patients with newly diagnosed MM, followed by APBSCT.

Patients between the ages of 18 to 65 year-old with newly diagnosed MM were recruited. PAD (bortezomib 1.3 mg/m² on days 1, 4, 8 & 11; doxorubicin 9 mg/m² on days 1 & 4; dexamethasone 40 mg on days 1-4, 8-11 & 15-18 during cycle 1 and days 1-4 during cycles 2-4) induction therapy was administered for four 28-days cycles, followed by autologous peripheral blood stem cell mobilization with cyclophosphamide 3 g/m² plus G-CSF 5 mg/kg/BD. Subsequently, APBSCT was performed with high dose melphalan 200 mg/m² conditioning.

A total of 25 patients has been recruited so far (male:female = 14:11). The age ranged from 44 to 65 year-old (median 53). Eleven patients were of IgG subtype, 6 were IgD, 4 were IgA and 4 were kappa light chain disease. By Durie-Salmon staging, 22 were stage III, 2 were stage II and 1 was stage I. Seventeen (68%) patients have completed the four cycles of PAD induction therapy, while 3 (12%) are still having on-going PAD induction. Five (20%) patients withdrew from the PAD therapy. One patient developed disease progression after 2 cycles of PAD, while the other 4 developed serious adverse events with the first cycle of PAD, including 1 patient each with severe bradycardia, atrial fibrillation, severe sensory neuropathy and pulmonary haemorrhage. Of the 18 patients who had evaluable response to PAD (i.e. 17 patients who completed four cycles of PAD and 1 who progressed on PAD induction), the results were 3 CR, 7 VGPR, 5 PR and 3 NR. Fourteen of the patients with at least PR received APBSCT. Post-APBSCT responses were so far evaluable in 11 patients with 6 CR, 4 VGPR and 1 PR. Hence, PAD is a feasible and effective upfront induction therapy for Chinese patients with MM resulting in a satisfactory response rate. Nevertheless, significant adverse events may occur even early on with the treatment. Subsequent APBSCT further improved the response rate but long-term survival rate remains to be established.

No relevant conflicts of interest to declare.