e15519 Background: Metronomic therapy (MT) is one of the most promising advances in cancer treatment strategy focused on both tumor cells and their microenvironment, specifically anti-angiogenic, immune and metabolic regulation. The treatment modality is a durable cytostatic drugs exposure with less toxicity. We investigated the efficacy of MT in point of prolonged duration of response (more than 6 months) in pts with the advanced resistant tumors. Methods: A total of 678 pts have been enrolled in the study and have been treated MT cyclophosphamide 50 mg (qd, PO) and methotrexate 2.5 mg (BID, PO) twice per week dosing schedule until progression. 508 pts (75%) had disease progression during first 6 months. Long-term efficacy (more than 6 months) was assessed in 170 pts (25%). The study population characteristics were female 122 (72%) vs male 48 (28%). Among the enrolled pts median age was 70 years (range from 37 to 91 years). ECOG status ranged from 0 to 4 (median - 1). The majority of pts received MT as a 2nd and 3rd line (57%) of the therapy (range from 1 to 11): 1-2 – 106 (62%), 3-4 - 52 (31%), 5 and more - 12 (7%). The distribution of pts by diagnosis is presented in the table 1. The majority of MT pts were represented by advanced clinical stage III-IV (97,6%): I - 1 (0,5%), II - 3 (2%), III - 7 (4%), IV - 159 (93,5%). MT commonly used in early-stages cancer in elderly patients with multiple comorbidities contraindicated to standard treatment. Most pts had two or multiple metastatic sites. Results: The ongoing long-term effect for MT indication was from 6 to 46 months. The main group consisted of the breast and colorectal cancer, 27% and 15%, respectively. The median time to progression was 9 months (16 months in CR was achieved (0,4%), 11 months and 9 months with a partial response (3,4%) and stable disease (21,2%), respectively). 12 (1,7%) pts are on ongoing long-term follow up more than 24 months. MT was well-tolerated. Drug related adverse events were described upon the study: hematological (10,2%, Gr 3-4 – 3,5%) vs non-hematological (6,6%, Gr 3-4 1,7%) toxicity. Conclusions: MT schedule demonstrated effectiveness in patients with advanced resistant tumors. The median duration of the effectiveness doesn’t depend on the line of therapy, tumor localization and objective response. The role of possible predictive markers of clinical benefit is question of further trials. [Table: see text]