Clinical studies of adults with X-linked hypophosphatemia (XLH)
have shown that CRYSVITA can help by:
The risks and benefits of CRYSVITA treatment
were studied in a total of
148 adults with XLH
- Number of patients: 134
- Ages: 19 to 66 years
- Length of treatment: 48 weeks
- Number of patients: 14
- Ages: 25 to 52 years
- Length of treatment: 48 weeks
- Phosphorus is a mineral that is important for healthy bones. Adults with XLH don’t have enough phosphorus, leading to weakening of their bones.
- In Study 4, adults with XLH were given either CRYSVITA or a placebo every 4 weeks for 24 weeks, and the amount of phosphorus in their blood, described as serum phosphorus, was measured. At Week 24, adults who started on placebo were switched to CRYSVITA every 4 weeks. Both groups were re-evaluated at Week 48.
CRYSVITA helped increase and maintain serum
phosphorus levels within
the normal range*
In Study 4, 68 adults received CRYSVITA and 66 adults received placebo every 4 weeks for 24 weeks. At Week 24, all 134 adults received CRYSVITA for 24 weeks.
*Normal levels of serum phosphorus for this group of patients ranged from 2.5 to 4.5 milligrams/deciliter (mg/dL). The normal range of serum phosphorus varies by age and sex.
At baseline, patients in both the CRYSVITA and placebo groups had phosphorus levels below the normal range. After 24 weeks of treatment with CRYSVITA or placebo, more patients achieved serum phosphorus levels within the normal range in the CRYSVITA group than in the placebo group. After 24 weeks of treatment, all patients were placed on CRYSVITA. Patients receiving CRYSVITA maintained their serum phosphorus levels through Week 48.
CRYSVITA helped heal fractures
In Study 4, 68 adults received CRYSVITA for 48 weeks and 66 adults received placebo for 24 weeks and then CRYSVITA for 24 weeks. At the beginning of Study 4, there were 65 total fractures in the CRYSVITA group and 91 total fractures in the placebo group.
During treatment through Week 24, a total of 6 new fractures or pseudofractures appeared in 68 patients in the CRYSVITA group, compared to 8 new abnormalities in 66 patients in the placebo group.
Softening and weakening of the bones is called osteomalacia.
- Under normal conditions, minerals like phosphorus are continuously added to bones. This process, called mineralization, helps to keep bones strong.
- People with XLH don’t have enough phosphorus for bones to properly mineralize, which causes some parts of the bone to become “soft” and more likely to break.
CRYSVITA helped heal osteomalacia
In Study 5, small samples of bone were taken from 14 adults with XLH and examined for signs of healing of osteomalacia. Bone samples were taken before the patients started treatment with CRYSVITA and then again after the patients were treated with CRYSVITA every 4 weeks for 48 weeks.
Healing of osteomalacia was observed in 10 out of 14 (71%) patients. Their bone biopsies showed a 57% reduction in osteoid volume to bone volume (OV/BV), which is a measurement of unmineralized bone.
Adults with XLH often report joint stiffness as part of their disease symptoms. Osteomalacia and abnormalities of the bones and joints can lead to several physical symptoms of disease that can impact daily life.
CRYSVITA improved XLH-related joint stiffness in adults
In Study 4, 68 adults received CRYSVITA and 66 adults received placebo every 4 weeks for 24 weeks.
In Study 4, patient-reported stiffness was measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). At Week 24, CRYSVITA showed improvement from baseline (–7.9) compared to placebo (+0.3) in the stiffness severity score (range 0 to 100; lower scores reflect symptom improvement).