This was a multicenter, prospective, interventional study designed to evaluate the efficacy and safety of denosumab in the prevention of CTIBL in Japanese GIC patients. The protocol was performed in accordance with the Declaration of Helsinki, Japanese ethical guidelines on clinical research, and Ethical Guidelines for Clinical Studies and was registered with the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (protocol ID UMIN000023855). The date of first registration was 31/August/2016. The enrollment period was from 01/March/2017 to 28/February/2018. Written informed consent was obtained from all patients, and protocol approval was obtained from the clinical research ethics review board of Sapporo City General Hospital and the each participating institutions in Japan.
All patients fulfilled the following criteria: histologically confirmed GIC (colorectal and non-colorectal cancers), including esophageal, gastric, pancreatic, and biliary cancer; no prior treatment (e.g., radiation therapy or chemotherapy) for these cancers; scheduled premedication with periodic glucocorticoids to prevent chemotherapy-induced nausea and vomiting or allergic reactions that was scheduled weekly, biweekly, or triweekly and in which >4-week steroid-free intervals were not allowed; age 40 to 90 years; a clinical risk score in the Japanese Society for Bone and Mineral Research (JSBMR) updated guidelines of 3 or more, which was defined as the optimal cutoff score for pharmacologic intervention to prevent steroid-induced osteoporosis . The following exclusion criteria were used: previous or current regular steroid use, regular bisphosphonate or denosumab use; regimens that included steroid-free intervals of >4 weeks; patients in which dual-energy x-ray absorptiometry (DXA) could not be performed due to their inability to maintain posture; patients who had previously undergone a total or partial gastrectomy; premenopausal women; serum calcium levels under 8.0 mg/dl; serum creatinine levels 1.5 mg/dl or higher; ongoing dental treatment.
BMD was measured with DXA of the lumbar spine (L2, L3, and L4 posteroanterior views) and the proximal left femur using the Hologic Discovery A or Ci or Horizon C (Hologic, Inc., Waltham, MA, USA) densitometers according to the manufacturer’s protocols. A daily quality control test was performed using the manufacturer-recommended phantom to ensure that observed density changes were not due to machine and/or operator variability. All technicians responsible for measuring BMD were blinded. T-scores were calculated by dividing the difference between the patient’s measured BMD and the mean BMD of healthy young adults matched for gender and ethnic group, and by expressing the difference relative to the young adult population standard deviation (SD). Z-scores were calculated by dividing the difference between the patient’s measured BMD and the age-matched mean BMD expected for the patient’s peers (a healthy normal subject matched for age, gender, and ethnic group) by the age-matched population SD.
Bone turnover markers
Two serum bone turnover markers (BTM), sBAP and sNTX, were measured. All assays were performed by SRL Inc. (Tokyo, Japan). All blood samples were collected in the morning after ≥8 h of fasting. sBAP levels were measured by a completely automated chemiluminescent enzyme immunoassay using a Beckman Coulter Access Ostase (Beckman Coulter, Inc., CA, USA) with a reference range of 3.7–20.9 µg/L for men, 2.9–14.5 µg/L for premenopausal women, and 3.8–22.6 µg/L for postmenopausal women. sNTX levels were measured using a completely automated enzyme-linked immunosorbent assay (ELISA) with Osteomark NTx Serum ELISA Test Kits (Alere Inc., WA, USA). The reference ranges for men and premenopausal and postmenopausal women were 9.5–17.7, 7.5–16.5, and 10.7–24.0 nmol bone collagen equivalent (BCE)/L, respectively.
Health-Related Quality of Life (QOL) Measurements
We used the Japanese Osteoporosis Quality of Life Questionnaire (JOQOL), which was established by the JSBMR, to measure and assess the QOL of Japanese osteoporotic patients. The JOQOL instrument consists of 6 domains and 38 items that are based on the Osteoporosis Assessment Questionnaire and the Quality of Life Questionnaire of the European Foundation of Osteoporosis, with some added questions specific to Japanese lifestyle . Higher scores indicated a better QOL, and each item was scored with a point scale from 0 to 4, with a maximum total score of 152 points. The use of JOQOL was approved by the JSBMR secretariat.
Diagnosis of Vertebral Fractures
A vertebral fracture was defined as new when it occurred in a vertebra that was not fractured at baseline. A fracture adjudication process that consisted of quantitative morphometry (QM) by a central committee radiologist without any information on the patient was used to confirm the presence of a new vertebral fracture. QM was done as follows: an independent experienced research assistant marked six points per vertebra, defining the anterior (ha), posterior (hp), and middle (hm) vertebral heights . In addition, the following ratios were calculated:
Anterior-posterior ratio (APR) = ha/hp
Middle-anterior ratio (MAR) = hm/ha
Middle-posterior ratio (MPR) = hm/hp
An existing fracture was defined as an APR of less than 0.75 or a MAR or MPR less than 0.8 at baseline. A new vertebral fracture was defined as an electronically measured decrease from baseline of at least 20% and a decrease of at least 4 mm in the each vertebral height.
The primary endpoint was BMD change in the L2-L4 lumbar spine (LS), which is considered the optimum site for monitoring treatment response , measured by DXA from baseline to 16 weeks after starting chemotherapy. Secondary endpoints included the percent changes from baseline in BTM levels, the safety profiles of denosumab, new fractures and changes in JOQOL and BMD in the femoral neck (FN) or total hip (TH), which is considered the optimum sites for predicting the risk of a hip fracture [13, 14, 15, 16, 17, 18]. For new fractures and jaw osteonecrosis we collected 2-year minimum follow-up data from the final case’s denosumab start date to February 29th, 2020.
The safety of the chemotherapy regimen were assessed by the study physicians at each visit. The study physicians all assessed if any adverse events (AEs) were related to the chemotherapy drugs at that time. AEs were graded using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 4.03.
In ESPRESSO-01 the average BMD reduction rate was −1.89%. Assuming that the lower limit of the 95% confidence of the BMD variation rate would exceed −1.89%, an estimated sample size of 36 was estimated based on a two-sided alpha value of 0.05 and a power of 90%. We estimated that 45 patients would be needed to achieve the required number of final cases assuming 20% attrition. Patient characteristics were summarized using descriptive statistics. Steroid dose intensity was calculated by dividing the total dose by the number of treatment weeks. Changes in BMD, BTM levels, and JOQOL scores from baseline to 16 weeks after chemotherapy start were examined using a paired samples t-test. The cross-trial comparisons between ESPRESSO-01 and -02 for adverse events were analyzed using the chi-squared test. Fisher’s exact test was used when the frequency of any cell of the contingency table was ≤5. Statistical significance was set at P < 0.05. Statistical calculations were performed using SPSS for Macintosh (release 24.0; SPSS Inc., Chicago, IL, USA).