Would Be Cyclophosphamide, Thalidomide and Dexamethasone (CTD) a Possible Treatment For Multiple Myeloma Where Is Not Possible New Drugs?

Nowadays, the best evidence for symptomatic patients with Multiple Myeloma (MM) is initial induction therapy with more than two drugs that contains bortezomib. If patients are eligible it is established the use of high dose chemotherapy and autologous stem cell transplantation (ASCT). We do not have to prescribe in Brazilian public health service, due to economic reasons, new drugs such as: bortezomib and lenalidomide. On the other hand, it is known that Cyclophosphamide, thalidomide and dexamethasone (CTD) regimen is an effective primary therapy for MM and it is widely used in some countries such as United Kingdom. We have been prescribing for first line therapy CTD regimen in our clinical practice for approximately 4 years. Thus, we performed a retrospective analysis of patients with MM treated with CTD regimen in the Instituto do Câncer do Estado de São Paulo. Here we present response rate, reduction dose rate, toxicity rate and progression free survival (PFS) and overall survival (OS).

We studied 71 patients that were submitted as first line treatment CTD, during 2006-2012. This regimen consists: Cyclophosphamide 500mg orally on days 1, 8, 15; Thalidomide 100mg orally on days 1 to 28 and Dexamethasone 40mg orally on days 1 to 5 and 14 to 18, every 30 days. To sensitive and eligible patients, we have submitted them for  ASCT. PFS and OS were calculated by the Kaplan-Meier method. PFS was calculated from the start of treatment until progression or death or last follow-up and OS until death or last follow-up. GraphPad Prism (v5.0) software was used for statistical calculations, and P values < 0.05 were considered to be statistically significant.

In the 71 patients, 54.2% were male patients, the median age was 57.81 years old (± 7.96). Out of the 71 patients (78.7%), were classified by Durie Salmon staging as IIIA or IIIB and 30% presented stage III for the International Staging System (ISS). Fifty seven (80.2%) were considered eligible for ASCT in the beginning of treatment. Moreover, the evidences of end-organ damage felt related to the plasma cell disorder were: lytic lesions 78.6%; anemia 51.4%, renal failure 20% and hypercalcemia 11.4%. The median of CTD cycles prescribed was 6.44 (± 2.62) and 47.1% were treated in the beginning without adjustment doses. It was evidenced 5.63% deaths related to the treatment. It was observed adjustment doses after 1^st cycle in 35.7% of patients due to: peripheral neuropathy 36%, tremor 16%, thrombosis 12%, bradycardia 12% and others 24%. It was observed in 71 patients: 6 (8.45%) stable disease (SD); 4 (5.63%) progressive disease (PD); 26 (36.66%) partial response (PR); 15 (21.1%) very good partial response (VGPR) and 16 (22.53%) complete response (CR), it was not possible to analyze 4 (5.63%) patients due to death. Of total eligible patients to ASCT, 57.62% were submitted for ASCT and in this moment 6.7% have been preparing for ASCT. The median of PFS was 29.2 months (CI 95% 0,22-0,66) and  median of OS was not achieved. It was observed difference in OS between patients with stage III for the ISS: 28,92 months versus (vs) patients with stage I and II median not reached, p = 0.0105. PFS study demonstrated curves that patients responding to CTD at least VGPR (VGPR+CR) presented better median PFS 37.48 months than others patients (PR+PD+SD) 17.93 months, p=0.0018.  Only patients that presented PD and SD response to CTD had a significantly shorter OS median 19.21 months than patients responses at least PR (PR+VGPR+RC) median was not reached, p < 0.0001.

We conclude that CTD is a feasible regimen where is not possible to prescribe new drugs, with acceptable toxicity. Moreover, patients that presented at least VGPR and at least PR to CTD demonstrated better PFS and OS, respectively.

No relevant conflicts of interest to declare.