An observational study on the efficacy and safety of zoledronic acid (ZA) in patients with non-small cell lung cancer (NSCLC) patients with bone metastases with high urine n-telopeptide (uNTX) at diagnosis (C-TONG 0801).

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e19541 Background: A retrospective study showed that bone metastatic NSCLC patients with high uNTX levels at diagnosis had a higher skeletal related event (SRE) and an increased death risk than that with lower uNTX levels. However, Patients with normalized uNTX levels after three months ZA treatment associated with lower SRE and better overall survival compared with those patients with continuously elevated uNTX levels. The present study prospectively investigated the relationship between SRE incidence and normalization of uNTX as well as the long-term safety of ZA in Chinese NSCLC patients with bone metastases. Methods: The NSCLC patients with bone metastasis, high uNTX levels (≥50 nmol/mmol) at diagnosis and treated with ZA (4mg, iv drip, every 3-4 weeks) more than 3 months were included to the study. All the patients continuously received ZA treatment and the standard chemotherapy. Urinary NTX was measured at baseline and 3, 6, 9 months. Clinical efficacies were measured with SREs rate at 12 months, annual SRE incidence, time to first SRE and survival. Patients were stratified into continued elevated uNTX levels group (CEG) and normalized uNTX levels group (NG). Results: 158 patients were enrolled. 51 and 99 patients were included into CEG and NG group respectively. uNTX Normalization rate after 3 month ZA treatment was 62.7% (99/158). For the all group, the SRE rate at 12 months is 14.65%, the mean annual SRE incidence was 0.48 events/year and median time to first SRE was 6.03 months. There are no differences between CEG and NG in term of annual SRE incidence (0.51 vs 0.47 events/year, P=0.89), SRE rate at 12 months (15.69% v 14.14%, P=0.80) and time to first SRE (4.61 vs 7.40 months, P=0.72). However, the patients in CEG had significantly poor overall survival than NG patients (16 vs >21 months, P=0.05). ZA was generally well tolerated. Conclusions: This is first prospectively study of the value of normalization uNTX in NSCLC patient with bone metastasis. The results confirmed that continued elevated NTX level during ZA treatment was a poor prognostic fact.