A Phase 4 interventional study of Teriparatide Pen Injector and Zoledronic Acid in Osteogenesis Imperfecta, sponsored by University of Edinburgh. Completed at 23 sites in 2 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-11.
Sponsored by University of Edinburgh · Phase 4, Interventional, and Treatment
Osteogenesis imperfecta (OI) is an inherited skeletal disorder characterised by increased risk of fragility fractures. Bisphosphonates are frequently prescribed for adult patients with OI with the aim of preventing fractures but the evidence base for efficacy is poor. Recent evidence suggests that the bone anabolic agent teriparatide (TPTD) increases bone mineral density (BMD) and may have the potential to prevent fractures in OI.
The purpose of the TOPaZ Trial is to investigate if a a two-year course of teriparatide (TPTD) followed by antiresorptive therapy with a single infusion of zoledronic acid (ZA) in adults with OI reduces the proportion of patients who experience a fracture as compared with standard care
Adult patients with a clinical diagnosis of OI who are willing and able to give informed consent and who do not have contraindications to the study medications will be recruited from participating sites. Participants will be randomised 1:1 to receive either standard care for the duration of the trial or TPTD for 24 months followed by a single infusion of ZA, or another antiresorptive agent in the event that ZA is contraindicated.
Participants will attend recruiting centres for a Baseline/Screening visit, at 12 months, 24 months and at the end of the trial for formal study visits with telephone calls every 6 months from a site research nurse. Participants randomised to TPTD will also attend recruiting centre at regular intervals during the 24 month treatment period to collect new supplies of TPTD.
Osteogenesis imperfecta (OI) is an inherited skeletal disorder characterised by increased risk of fragility fractures. Bisphosphonates are frequently prescribed for adult patients with OI with the aim of preventing fractures but the evidence base for efficacy is poor. Recent evidence suggests that the bone anabolic agent teriparatide (TPTD) increases bone mineral density (BMD) and may have the potential to prevent fractures in OI.
The purpose of the TOPaZ Trial is to investigate if a a two-year course of teriparatide (TPTD) followed by antiresorptive therapy with a single infusion of zoledronic acid (ZA) in adults with OI reduces the proportion of patients who experience a fracture as compared with standard care.
The trial has a number of secondary objectives which aim to investigate if a two-year course of TPTD followed by antiresorptive therapy with a single infusion of ZA in adults with OI reduces the total number of fractures, reduces the risk of vertebral fractures; or affects bone pain, quality of life and functional status as compared with standard care. There is also a planned mechanistic analysis to understand which baseline characteristics of adults with OI, such as age, clinical subtype of OI, genetic diagnosis, bone turnover, BMD, and previous treatment influences the occurrence of fractures and/or the response to treatment
Adult patients with a clinical diagnosis of OI who are willing and able to give informed consent and who do not have contraindications to the study medications will be recruited from participating sites. Participants will be randomised 1:1 to receive either standard care for the duration of the trial or TPTD for 24 months followed by a single infusion of ZA, or another antiresorptive agent in the event that ZA is contraindicated. Exclusion criteria include: current or previous treatment with an investigational (non-licensed experimental) drug with effects on bone metabolism, contraindication to TPTD or ZA, women of childbearing potential not using highly effective methods of contraception, pregnancy, women that are breastfeeding or age \<18 years.
Participants will attend recruiting centres for a Baseline/Screening visit, at 12 months, 24 months and at the end of the trial for formal study visits with telephone calls every 6 months from a site research nurse. Participants randomised to TPTD will also attend recruiting centre at regular intervals during the 24 month treatment period to collect new supplies of TPTD.
The baseline assessment will include dual energy x-ray absorptiometry (DEXA), spine x-rays, safety bloods, medical and fracture history, pain (brief pain inventory, BPI) and quality of life (SF36, HAQ, EQ5D, PSQI). Blood will be taken for genetic analysis and for analysis of biochemical markers of bone turnover. In some centres, a high resolution quantitative CT scan (HRQCT) of the wrist and tibia will be performed. Participants will be seen after 12 months when bloods, questionnaires and HRQTC will be repeated; at 24 months when bloods, questionnaires, DEXA and HRQCT will be repeated. At the end of the study participants will undergo DEXA, spine x-rays, HRQCT and bloods and questionnaires will be repeated. Information on adverse events and fractures will be collected throughout the study and participants suspected to have fractures will have x-ray or other imaging to confirm the presence of fractures.
84 studies on the registry are indexed under Osteogenesis Imperfecta; 20 are open to participants now.
This study's enrollment of 350 is above the median of 28 across 60 interventional studies indexed under Osteogenesis Imperfecta.
Browse Osteogenesis Imperfecta studies →University of Edinburgh is the lead sponsor of 403 studies on the registry; 64 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Teriparatide (TPTD) 20mcg daily using Teriparatide Pen Injector, given subcutaneously using a self-administered injection device for two years (24 months) followed by a single intravenous 5mg infusion of zoledronic acid.
Drug: Teriparatide Pen Injector · Drug: Zoledronic Acid
Continuation of existing bone modifying treatment (i.e. bisphosphonate treatment) or no active bone modifying treatment according to the clinical judgement of the local investigator.
Also known as: Forsteo, Forteo
Any brand or preparation may be used to deliver the required dose of 5mg
Also known as: Aclasta 5mg solution for infusion, Zoledronic acid 5mg/100ml solution for infusion
Incident clinical fractures validated by x-ray or other imaging
Proportion of participants experiencing a clinical fracture validated by x-ray or other imaging as compared to standard care
Time frame: Through study completion, approximately 5 years
Total number of incident vertebral fractures
Incident vertebral fractures assessed by imaging of the thoracic and lumbar spine and reviewed by an independent masked adjudicator using two spine x-rays collected at the start and end of the trial
Time frame: Baseline (0) and Final Trial Visit (5 years after baseline)
Total number of fractures
Total number of fractures experienced by participant defined as combination of validated clinical fractures, vertebral fractures and fractures reported by participants where imaging was not performed, was not feasible or where results were inconclusive
Time frame: Through study completion, approximately 5 years
Pain assessed by the Brief Pain Inventory (BPI) Short Form measure
Bone pain assessed by the Brief Pain Inventory (BPI) Short Form, a Patient Reported Outcome Measure completed at 4 time-points throughout the trial. The BPI gives two main scores - a pain severity score and a pain interference score. The pain severity score is calculated from the four questions (3-6) about pain intensity. Each item is rated from 0 (no pain) to 10 (pain as bad as you can imagine). The scores from the 4 questions are added together and then divided by 4, giving a severity score out of 10. The pain interference score corresponds to Question 9 responses. The seven sub-items are rated from 0 (does not interfere) to 10 (completely interferes). The scores are added together and divided by 7, giving an interference score out of 10. Question 2 (pain drawing diagram), Question 7 and Question 8 (pain relief treatment or medication) do not contribute to the scoring.
Time frame: Baseline (0), 12 months, 24 months and Final Trial Visit (5 years after baseline)
Quality of life assessed by the SF-36 (v1) Quality of Life
The SF-36 questionnaire consists of 36 generic health questions: 8 health domains of the questionnaire, each of which are summarised (Physical functioning score (10 items), Role-physical score (4 items), Bodily pain (2 items), General health score (5 items), Vitality score (4 items), Social functioning score (2 items), Role-emotional score (3 items), and Mental health score (5 items)). The resulting score for each domain is standardized, to obtain values ranging from 0 to 100, with higher values indicating a better quality of life.Two overall summary measures (physical and mental component scores) are calculated.
Time frame: Baseline, 12 months, 24 months and Final Trial Visit (5 years after baseline
Sleep quality assessed by the Pittsburgh Sleep Quality Index (PSQI) measure
Sleep quality as assessed by the Pittsburgh Sleep Quality Index, a Patient Reported Outcome Measure completed at 4 time-points throughout the trial. The Pittsburgh Sleep Quality Index contains 19 self-rated questions. The questions are combined to form seven 'component' scores, each of which has a range of 0-3 points. In all cases, a score of 0 indicates no difficulty while a score of 3 indicates severe difficulty. The seven component scores are added to yield one global score, ranging from 0-21 points, 0 indicating no difficulty and 21 indicating severe difficulties in all areas.
Time frame: Baseline (0), 12 months, 24 months and Final Trial Visit (5 years after baseline)
Functional status assessed by the Health Assessment Questionnaire (HAQ) measure
The HAQ includes 8 blocks of questions covering difficulties performing simple daily activities. There are 20 questions in total. A 4 point grading system is used to denote degree of difficulty (0=none, 1=some difficulty, 2=great difficulty, 3=not able to perform at all). Each item has a companion aids-devices variable used to record types of assistance the subject uses for his/her usual activities. These variables are coded from 0 to 3 (0 = No assistance is needed, 1 = A special device is used by the subject in his/her usual activities, 2 = The subject usually needs help from another person, 3 = The subject usually needs BOTH a special device AND help from another person). The highest score reported for any component question of the 8 categories determines the score for that category. A global score is calculated by summing the scores for each of the categories and dividing by the number of categories answered.
Time frame: Baseline (0), 12 months, 24 months and Final Trial Visit (5 years after baseline)
Adverse events
All adverse events reported throughout the duration of the trial. Summarised by treatment and by severity, causality and seriousness, reporting both the number of events and the number of patients experiencing a given event.
Time frame: Through study completion, approximately 5 years
Mechanistic analyses (ITT)
Relationship between gender, clinical OI subtype, lowest Bone Mineral Density T score at spine or hip (≤ -2.5 or \> -2.5)), type of genetic mutation (mutations of COLIA1 or COLIA2 and biochemical markers of bone turnover with fracture occurrence and response to treatment. Descriptive statistics by treatment group for each subgroup will be presented. The primary outcome, defined as the proportion of participants experiencing a clinical fracture validated by x-ray or other imaging, will be analysed for these subgroups. The interaction between subgroup and treatment will be included in the primary and secondary analysis models to determine if the treatment effect differs by subgroup.
Time frame: Biological samples collected at Baseline (0), 12 months, 24 months and Final Trial Visit (5 years after baseline)
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No — Anonymised aggregate data only will be shared.
This study is completed, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Teriparatide · Zoledronic Acid