Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 14 4 2020 10 07 226 231 Rony Benson Department of Medical Oncology, Regional Cancer Centre, Thiruvananthapuram 695011, India Sreejith Nair Department of Medical Oncology, Regional Cancer Centre, Thiruvananthapuram 695011, India Geetha Narayanan Department of Medical Oncology, Regional Cancer Centre, Thiruvananthapuram 695011, India 2019 10 25 2020 05 04 Background: The half-life of free light chain is short and can be used as an early marker for tumor response in patients with multiple myeloma [MM]. This prospective study is aimed at evaluating whether early light chain response can predict response to treatment in patients with MM. Materials and Methods: Thirty six patients with a diagnosis of MM and with an abnormal to normal light chain ratio of > 10 were included in this study. Results: The median age at presentation was 56 years. Fourteen patients had lambda light chain disease, whereas 22 patients had kappa light chain disease. Twenty-four patients [66.6%] had reduction of abnormal to normal light chain ratio to < 10 after 2 cycles, of whom 15 [62.5%] achieved a CR or VGPR after 6 cycles. Among 12 patients who did not have reduction of abnormal to normal light chain ratio to < 10, only 1 patient achieved CR while 11 patients [91.6%] achieved a PR or less[Fishers exact p=0.004]. Median follow-up was 13 months. Median progression-free survival for the entire cohort was 15 months. One-year Progression-Free Survival was 77% vs 57.1%, [p= 0.008], respectively for patients with early normalization and those who did not show early normalization. Conclusion: Early light chain response after 2 cycles of chemotherapy is a good predictor for treatment response in patients with MM treated with bortezomib based chemotherapy. Treatment intensification based on early light chain response merits further evaluation in a prospective trial https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/1199 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/1199/863