The safety and efficacy of diclofenac sodium suppository as adjunctive opioids in the treatment of cancer pain: A prospective, multi-center, real-world study.
Authors: He Jianping , Zhang Yan , Wu Yaogui , Zhao Huarong , Yang Jinqi , Zhang Zhenhua , Qiao Hongmei , Cao Yufeng , Yan Zhenhua , Wang Yang , Ji Guoyi , Zhan Shudong , Zhang Yarui , Sun Yu , Meng Peng , Zhang Xiuliang , Wang Xiang , Guo Zhifeng , Ren Shoulei , Zhang Wentian 
Published: June 2024

12055 Background: Cancer pain is one of the most common and unbearable symptoms for cancer patients (pts), seriously affecting their quality of life. Diclofenac sodium is a potent third-generation non-steroidal anti-inflammatory drug known for its significant analgesic, anti-inflammatory, and antipyretic effects. It is commonly used to treat different types of cancer pain. The objective of this study was to assess the safety and effectiveness of diclofenac sodium suppository when used alongside opioids for managing cancer pain in pts with solid tumors. Methods: In this prospective, multi-center, real-world study, we enrolled pts diagnosed with malignancy, Eastern Cooperative Oncology Group (ECOG) performance status of 0-3, numeric rating scale (NRS) score ≥ 3, and sustained cancer pain, who required additional analgesic medication were enrolled. Diclofenac sodium suppository is an anal administration suppository, prescribed once a day at a dosage of 50 mg. This study was conducted across 20 centers to observe the clinical characteristics of pain relief in pts with cancer pain . The primary endpoint of the study was to assess the safety of the medication. The secondary endpoints included evaluating the incidence of breakthrough pain (BP), NRS score, and Brief Pain Inventory (BPI) score on the second and sixth days of medication. Results: Of the 506 pts that were screened, 437 pts met the inclusion criteria. This included 10 pts who did not receive planned treatment and 2 pts who did not undergo post-baseline efficacy evaluation. Among the 425 pts in the full analysis set (FAS), 261 were man, and 169 (39.8%) had baseline BP. The mean age was 63.0±11.3 years old. Among 425 response-evaluable pts, compared to the baseline, the incidence of BP was reduced on the second (20.0% vs 39.8%), and sixth days (14.8% vs 39.8%) of medication and the difference was statistically significant ( P < 0.001, P < 0.001). For pts with baseline BP, 56.2% and 66.9% pts achieved BP relief on the second and sixth days of medication, respectively. From the baseline evaluation, the mean NRS scores for the three visits (baseline, second day, sixth day) were 5.28 ± 1.71, 3.73 ± 1.71, and 2.91 ± 1.88, respectively. The mean pain intensity at each visit was decreased compared to the baseline, and the difference was statistically significant ( P < 0.001, P < 0.001). 427 pts were included for safety analysis and 5 pts experienced any grade treatment emergent adverse events (TEAEs). All TEAEs were grade 1-2. TEAE leading to treatment discontinuation was occurred in one pt. Conclusions: This study demonstrated that diclofenac sodium suppository was an effective treatment option for managing breakthrough pain in patients with persistent cancer pain who required additional analgesic therapy. Moreover, diclofenac sodium suppository was found to be well tolerated when administered anally.