Evaluation of Residual Minimum Response with Free Serum Light Chains in Patients with Multiple Myeloma Diagnosis

The International Myeloma Group has added the serum free light chain assay to the multiple myeloma response criteria, incorporating a new category of response: the strict complete response. This response requires, in addition to the negativization of immunofixation and the absence of clonal CPs in the bone marrow, the normalization of the free κ / λ ratio. This is a descriptive study with the main objective of identifying patients who were diagnosed at the National institute of cancerology and were able to characterize their response. We included 67 patients with thalidomide Dexamethasone-based regimens up to 72.5% and 27.5% regimens based on others Types of drugs,The chemotherapy regimens were 2 patients chemotherapy with VAD (vincristine, Dexamethasone and doxorubicin), 2 patients melphalan prednisone, patients CyborD (cyclophosphamide, bortezomib and Dexamethasone, and Tacydex (thalidomide, dexamethasone and cyclophosphamide), two patients had carfilzomib based regimen and one patient received daratumumab. 21 patients were transplanted hematopoietic cells 90% had autologous transplantation and 10% were transplanted in tandem with an average of 4 months between infusions of hematopoietic progenitors. After the exposure to the first line of treatment, the response was assessed in the total population at 3 months. We obtained clinical and laboratory reports available in the medical history to be able to classify the response according to current criteria, 48.3% achieved partial response and only 3 patients obtained complete response. The rest of the patients were protocolized for autologous transplantation The new response was evaluated at 6 months of treatment, reaching complete responses up to 33.8%. At 9 months a complete response was documented in 19.3%. Finally, at 12 months, most of the complete responses are reached up to 37% Information on the serum light chain ratio was obtained in 76% of patients included in the sample. Finding up to 93% patients with MM RCe. In our center, only 4 patients, the 7% of the total of the analyzed sample, presented a ratio of free light chains in abnormal serum. In all cases of abnormal quotient, this was above the upper limit, reflecting a relative overproduction of free kappa chains. Follow-up was achieved in twelve patients whose response was reached in the first 3 to 6 months, remaining with a negative light chain ratio Regarding the time in which the strict response was reached, 96.77% of the patients presented a complete response at 3 months and the serum light chain ratio was negativized. However, only 23.71% of the patients presented a response that presented complete response to 12 months were able to negativize the ratio of serum light chains. With a 95% confidence interval and a standard error of estimation of (2.24-6.09%) implying that the further the timeline advances, the lower the probability of negative light chain response. Male and female gender presented negative response at 3 and 9 months respectively. As for gender, there were no significant changes, 67% of the women had a strict complete response in the first 6 months, while 62% of the men had a complete complete response. With a 95% confidence interval and a standard error of estimation (2.90-8.40%) for the masculine gender and (3.51-8.68%) for the feminine gender. Finally, in comparison with the international staging system for multiple myeloma for patients who managed to respond to the first 3 months, 96.67% belonged to the ISS and 68% of the patients who presented a response at 6 months belonged to the ISS II group. 55.93% achieved complete complete responses at 12 months belonging to the ISS III group. With a 95% confidence interval and a standard error of estimation of ISS I (11.59-12.35%) for ISS II (3.28-9.38%) for ISS I, And (6.05-9.76%) for ISS III. During the last decade there have been important changes in the treatment of multiple myeloma that have resulted in an improvement in prognosis. Nowadays, we know that the inclusion of proteasome inhibitors as well as new agents and some low availability monoclonal antibodies in our medium have a profile that may be of future utility in these patients. As is well known, RC is rarely achieved with the use of conventional chemotherapy. This population, although the majority deal with the institutional scheme obtained extremely encouraging responses since more than half of those who achieved the complete response achieved the stricte complete response. Disclosures No relevant conflicts of interest to declare.