by ecancer reporter Vanessa Lane

Consolidation therapy, which is intended to further enhance the frequency and quality of response obtained with previous treatment phases, has traditionally been autologous stem cell transplant (ASCT) in transplant-eligible patients.

The strength of the data for novel therapies has led to their investigational use as part of consolidation therapy after ASCT.

In Phase II and III studies, these novel agents have been given either alone or in combination with one another for 2-5 months.

Results have shown consistent increases in complete response (CR) rates, even to a molecular or immunophenotypic level, in comparison with that seen after single or double ASCT.

In some studies, this response was associated with prolonged progression-free survival (PFS) and overall survival (OS) from the start of consolidation therapy. 

With the introduction of novel agents, most MM patients respond to induction therapy. Therefore, the next challenge is to maintain these responses, or even to improve them, to achieve prolonged PFS and, eventually, longer survival.

Three recent randomised trials have shown that lenalidomide maintenance was associated with prolonged PFS in MM; one showed a survival benefit. Two additional randomised trials have shown benefit of maintenance with bortezomib in terms of PFS and OS.

However, in these trials it was difficult to separate the value of maintenance from the variations in induction therapy between the two arms being tested.
Many questions remain in terms of whether maintenance therapy should be offered, which therapy should be given and how long it should be given for. The answers will partly depend on the patient profile, including risk.

In terms of duration, recent data suggest that a minimum of 8-12 months of post-ASCT immunomodulatory therapy should be considered.  Numerous ongoing studies are addressing these questions and will hopefully help elucidate the benefit of maintenance therapy and how it could be implemented into routine clinical practice.

Until these results become available, current practice in Europe is to restrict maintenance therapies to patients enrolled into clinical trials.