A Phase 2 interventional study of STS in Systemic Sclerosis, Dermatomyositis and iPPSD2, sponsored by University Hospital, Limoges. Recruiting at 11 sites in France. Open to participants aged 6 Months and older. Per ClinicalTrials.gov, last updated 2026-09-15.
Sponsored by University Hospital, Limoges · Phase 2, Interventional, and Treatment
Ectopic soft tissue calcifications or ossifications can complicate the course of numerous diseases; most of them are rare or very rare. Even if the clinical, radiological and pathological presentation of ectopic calcifications and ossifications are different, the same hypotheses are discussed considering their hypothetical pathophysiology. Indeed, high calcium phosphate product, local cellular lesions and abnormal transdifferentiation of mesenchymal cells are regularly evoked when pathophysiology of such calcifications or ossifications are discussed. Apart from several case reports that have not been confirmed so far, no medical treatments are available, leading to significant pain and impairment of quality of life for patients. Therefore, only surgical treatment can be proposed when the volume or the consequences of these calcifications/ossifications become too important.
Sodium thiosulfate (STS) is currently used as a cyanide poisoning antagonist and a chemoprotectant against adverse effects of several chemotherapies such as Cisplatin. Numerous case reports and several studies have revealed the potential interest of STS in the treatment of uremic induced vascular or soft tissues calcifications. Recently, our group has developed an expertise in the use of STS for the treatment of ectopic soft tissue calcifications or ossifications. Considering these promising preliminary data, and their limits, we developed a strategy to treat soft tissue calcifications or ossifications based on a local administration of STS. The first results of this therapeutic strategy are highly promising and the local or systemic safety is satisfactory so far. These preliminary data also reported by others deserve to be confirmed in a prospective study.
We propose in this project to conduct a prospective open controlled phase II trial in order to assess the efficacy and the safety of intralesional administration of STS for the treatment of calcifications secondary to dermatomyositis or systemic sclerosis and ectopic ossifications secondary to pseudo-hypoparathyroidism 1a type (PHP1A/iPPSD2) (inactivating parathyroid hormone / parathyroid-hormone-related peptid (PTH/PTHrP) signalling disorder).
610 studies on the registry are indexed under Scleroderma, Systemic; 218 are open to participants now.
This study's planned enrollment of 40 is close to the median of 37 across 446 interventional studies indexed under Scleroderma, Systemic.
Browse Scleroderma, Systemic studies →University Hospital, Limoges is the lead sponsor of 264 studies on the registry; 38 are open to participants now.
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Patient presenting with:
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.
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
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.
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.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
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.
M0-M6: run-in phase (control) M6-M12: STS treatment phase
Drug: STS
M0-M6 (run-in phase): medical care and follow-up as usual M6-M12 (STS phase): * Patients with iPPSD2 will be treated with subcutaneous infusion using a portable pump. * Patients with dermatomyositis or systemic sclerosis will be treated with repeated injections every two weeks. Patients will receive a maximal total number of 11 STS injections. M12: final visit (V5): clinical evaluation, photograph and CT scan of the treated lesion, pain and quality of life evaluation.
Change of the percentage of volume of the treated calcifications / ossifications
Calculation of percentage of volume evolution of the treated calcification / ossification between the beginning and the end of STS treatment, in each of the three diseases (dermatomyositis, systemic sclerosis and iPPSD2), evaluated on CT-scan measurements.
Time frame: between Month 6 and Month 12
Change of the volume of the treated calcifications / ossifications
Calculation of volume of the treated calcification / ossification at (i) inclusion, the end of the run-in period (6 month) and after 6 months of local injections of STS in each disease (12 month), evaluated on CT-scan measurements.
Time frame: Month 0, Month 6 and Month 12
Adverse events
Collection of adverse events (clinical and biological): causality, severity, and seriousness during the STS treatment.
Time frame: Month 12
Change of the Hounsfield density of the treated ectopic calcifications/ossifications
Hounsfield density analysis of the treated ectopic calcifications/ossifications at inclusion, the end of the run-in period (6 month) and after 6 months of local injections of STS (12 month), evaluated on CT-scan measurements.
Time frame: Month 0, Month 6 and Month 12
Change of the percentage of patient with a clinically pertinent variation in pain
Calculation of Percentage of patients with a clinically pertinent variation in pain evaluated with pain scales: difference in hetero-evaluation scale of pain in children (HEDEN) ≥ 2 (2-7 years old) between M0-M6 and M6-M12
Time frame: Between Month0 and Month 6 and Between Month 6 and Month 12
Change of the percentage of patient with a clinically pertinent variation in pain
Calculation of Percentage of patients with a clinically pertinent variation in pain evaluated with pain scales: difference in visual analogue pain intensity scale (VAS) score ≥ 2 (\> 7 years old) between M0-M6 and M6-M12
Time frame: Between Month0 and Month 6 and Between Month 6 and Month 12
Change of the percentage of patients with a clinically pertinent variation in quality of life
Calculation of percentage of patients with a clinically pertinent variation in quality of life : difference in PedsQL ≥ 5 (2-18 years old, using appropriates reports) between M0-M6 and M6-M12
Time frame: Between Month0 and Month 6 and Between Month 6 and Month 12
Change of the percentage of patients with a clinically pertinent variation in quality of life
Calculation of percentage of patients with a clinically pertinent variation in quality of life : difference in Short Form 36 (SF36) score ≥ 20 (\> 18 years old) between M0-M6 and M6-M12
Time frame: Between Month0 and Month 6 and Between Month 6 and Month 12
Started Jan 2020 (actual). Primary completion is estimated for Jun 2029, 113 months after the start.
Of 48 phase 2 interventional studies under Scleroderma, Systemic, half reached primary completion within 37 months of starting (the median), counting those still running; a quarter within 24 and three quarters within 83. This study's planned 113 months is above that.
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