What Factors Influence Response to Multiple Myeloma Treatment?

Two recent studies analyzed patients with multiple myeloma to identify factors that impacted response to therapy.

Patients who achieve a very good partial response (VGPR) or better have longer progression-free survival (PFS) than patients who have poorer responses to induction therapy. Patients who do not achieve maximum response after 4 cycles of induction therapy should continue induction therapy until maximum response is achieved.

PFS is an important endpoint that for many hematologic malignancies, including multiple myeloma. As one of the primary survival endpoints, it is essential that investigators identify what patient characteristics lead to longer-term responses to improve treatment. In one study, investigators analyzed patients with multiple myeloma to identify any common features that led to longer term responses.

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Patients from the UK MRC Myeloma IX (M-IX) and NCRI Myeloma XI (M-XI) trials were studied and separated between long-term response post induction (PFS ≥48 months) and those with PFS <48 months. Patients in the M-IX trial received either alkylating therapy (cyclophosphamide, vincristine, doxorubicin [Adriamycin], dexamethasone [CVAD] or melphalan, prednisone [MP]) or thalidomide-based induction (cyclophosphamide, thalidomide, dexamethasone [CTD]) therapy while patients in the M-XI trial received either thalidomide or lenalidomide-based induction (CTD or cyclophosphamide, lenalidomide [Revlimid], dexamethasone [CRD]) and response-based bortezomib intensification (cyclophosphamide, bortezomib [Velcade], dexamethasone [CVD]).

^{1In both trials, a higher number of transplant-eligible patients had a PFS ≥48 months compared with patients who were ineligible for transplant (M-IX, 25.8% vs 7%, respectively; M-XI, 34.2% vs 10.2%). Longer PFS also translated to longer overall survival in both trials. Factors that were associated with PFS ≥48 months included International Staging System I and lower performance status (WHO). Patients with high-risk lesions (gain [1q] or del[17p]) were more frequently in the PFS <48-month group. In a multivariable analysis of baseline parameters, absence of gain [1q] was the only genetic factor associated with PFS ≥48 months in transplant-ineligible patients. In comparison, absence of all high-risk lesions was associated with PFS ≥48 months in transplant-eligible patients.1Continue reading on The American Journal of Managed Care.}