Newly Diagnosed Myeloma Pateints Are at Risk of Venous Thrombotic Events - High Risk Patients Need To Be Identified and Recieve Thromboprophylaxis: The MRC Experience.
Authors: Davies Faith E. , Child J. Anthony , Hawkins Kim , Bell Susan , Brown Julia , Drayson Mark T. , Jackson Graham H. , Morgan Gareth J. 
Published: April 2020

Standard treatment for younger patients with presenting myeloma is VAD followed by high-dose melphalan with stem cell support. However this regimen requires a central venous catheter with risks of recurrent line infections and central venous thrombus. A number of oral alternatives have been used including dexamethasone (Dex), thalidomide (Thal) or combinations (Thal/Dex), although to date no randomized control trial has compared an intravenous with oral induction therapy. In older patients melphalan/prednisolone (MP) remains the standard approach. Thal combinations (MPT, CTD, DVdT) improve response rates and providing side effects can be managed effectively may also be appropriate for an elderly population. Patients with myeloma have an increased risk of venous thrombotic events (VTEs), and presenting patients receiving Thal may be at increased risk due to bulk disease. Combination with anthracyclines may also exacerbate this risk. The MRC Myeloma IX trial has been designed to address some of these issues. Younger patients are randomized to receive intravenous CVAD or an oral Thal containing regimen, CTD prior to autologous transplantation; older patients are randomized to MP or the Thal containing regimen, CTDa. At trial initiation (May 2003) physicians were advised that patients should start low-dose Thal (100mg od in the intensive and 50mg od in the non-intensive arm) and slowly dose escalate to 200mg. Patients at high risk of VTE should be considered for full anticoagulation with either warfarin or LMWH. As of Aug 2004 420 patients (239 intensive, 181 non-intensive) have been randomized and a total of 30 VTEs in 28 patients have been reported (22 intensive, 6 non-intensive). In the intensive arm there were 8 DVT, 9 PE and 7 line-related thromboses. In the non-intensive arm there were 4 DVT and 2 PE.

CVAD CTD CTDa MP DVT 4.2% 2.5% 4.4% 0% PE 1.7% 5.8% 2.2% 0% Line related 5.0% 0.8% NA NA Total 10.9% 9.1% 6.6% 0%

The median time from randomization to DVT/PE was 54.5 days (range 15–113). 4 patients were identified who had additional risk factors (2 immobility, 1 recent operation, 1 renal failure). Only 1 patient was receiving prophylaxis having previously suffered a DVT. There was one PE-related death. Importantly 2 PE and 5 DVT occurred in patients not receiving Thal therapy. All central thrombosis occurred in relation to the central line. In the non-intensive arm the addition of Thal increased VTE risk compared to MP. In conclusion myeloma patients have an increased incidence of VTE (5.9%–8.3%) although in this study so far patients on MP appear to have no excess thrombotic risk. Patients receiving infusional regimes are also at increased risk of line-related events (additional 5.0%). Using the combination of a slowly increasing Thal dose and thromboprophylaxis based on identification of high risk patients the addition of Thal marginally increased DVT/PE risk over and above the risk seen in patients with infusional regimens, but even in a large study such as this the number of events are too small to make firm recommendations. Currently our advice remains unchanged and ALL high risk patients should receive thromboprophylaxis.