Children Patient Case Studies
See how CRYSVITA may help your patients
with XLH
Medical history*
Pediatric evaluation
- 20-month-old male presented with bowed legs
- Bowing present since birth, worsened once patient started walking
- Other physical exam findings: waddling gait, cannot run well
- Suspected diagnosis: congenital bilateral knee bowing
- At 24-month exam, worsened bowing of legs and waddling gait noted
- X-ray findings: bilateral bowing of femur and tibia; cupping of distal femur, proximal and distal tibia and fibula
- Suspected diagnosis: rickets
Endocrinology and genetics evaluations
- Physical exam at 24.5 months: severe knee bowing, intercondylar distance 5 cm, short stature, height: 1st percentile (see Growth chart, A)
- X-rays: metaphyseal flaring at wrists and ankles
- Laboratory findings (see Table)
- Suspected diagnosis: hypophosphatemic rickets
- Upon genetic evaluation at 25 months, pathologic PHEX variant identified, mother negative
Growth chart
FOOTNOTES
Patient growth evolution prior to and after CRYSVITA.
A: At 24.5 months, the patient was in the 1st percentile for height.
B: At enrollment, the patient was in the 5th percentile for height.
C: While on CRYSVITA, the patient was in the 10th percentile for height.
†The reference percentiles on the graph are combined from the two clinical growth charts for boys 2-20 years of age provided by the Centers for Disease Control and Prevention.
Diagnosis and initial treatment
- Spontaneous XLH
- Treatment: oral calcitriol and phosphate
Disease progression
Evaluation at academic center
- Physical exam at 29 months: femoral bowing; obvious genu varus – knees 4.5 cm apart, ankles touching; bilateral tibial bowing
- Height 5th percentile (see Growth chart, B)
- X-rays: metaphyseal widening at wrists, mild cupping of distal radius and ulna
- Knees: marked bowing, cupping and fraying of growth plates (see X-rays)
- Laboratory findings (see Table)
- Enrolled in CRYSVITA clinical trial at 31 months
CRYSVITA treatment, 64 weeks
- Physical exam at 46 months: femoral bowing; bilateral tibial bowing
- Genu varum resolved; knees straight
- Height 10th percentile (see Growth chart, C)
- X-rays: resolved cupping and fraying of metaphysis of radius and ulna; improved fraying of femoral metaphysis; decreased widening of femoral growth plate (see X-rays)
- Laboratory findings: tests improved (see Table)
X-rays: evolution of rickets and lower limb deformity
Prior to CRYSVITA
(29 months old)
CRYSVITA 40 weeks
(40 months old)
CRYSVITA 64 weeks
(46 months old)
Prior to CRYSVITA
(29 months old)
CRYSVITA 40 weeks
(40 months old)
CRYSVITA 64 weeks
(46 months old)
Laboratory test results
| Test (reference rangea unit) | Results (age) | |||
|---|---|---|---|---|
| Early evaluation (24.5 months) |
Prior to CRYSVITA (31 months) |
CRYSVITA 40 weeks (40 months) |
CRYSVITA 64 weeks (46 months) |
|
| Serum phosphorus (4.3-6.8 mg/dL) | 2.9 | 2.9 | 3.7 | 4 |
| TmP/GFR (4.0-5.2 mg/dL) | n/a | 2.8 | 3.7 | 4 |
| 25(OH)D (≥20 ng/mL) | 26 | 24 | 36 | 26 |
| ALP (156-369 U/L) | 636 | 459 | 283 | 299 |
| Serum calcium (9.2-10.5 mg/dL) | 9.4 | 9.5 | 9.6 | 9.6 |
| PTH (10-65 pg/mL) | 56 | 20 | 36 | 23 |
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FOOTNOTES
25(OH)D, 25-hydroxy vitamin D (calcifediol); ALP, alkaline phosphatase; PTH, parathyroid hormone; TmP/GFR, ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate.
aIndicates normal range, age, and sex matched. Note that normal range values may vary depending on reference dataset. The range in this table was provided by the treating physician.
Summary
- Patient presented with symptoms at 20 months and underwent several specialty evaluations before XLH diagnosis at 25 months
- Conventional therapy initiated; XLH symptoms continued to progress
- Patient enrolled in CRYSVITA clinical trial at 31 months
- After 64 weeks on CRYSVITA, patient demonstrated improvements in laboratory findings and lower limb deformity
*The information for this case study was provided courtesy of Dr. Anthony Portale, Division of Pediatric Nephrology, UCSF Benioff Children’s Hospital, San Francisco. This case study represents a real patient and is intended to be illustrative, not a recommendation for treatment or management. Not all patients will respond the same to CRYSVITA treatment. Results may vary. This case study does not claim to represent typical results.
Medical history*
Orthopedic evaluation
- 19-month-old female presented with hip clicks
- X-ray findings: normal hips
Endocrinology evaluation
- Physical exam at 24 months: waddling gait, mild bowing at knees, no pain
- Reported poor weight gain: from 25th percentile at 9 months to between 3rd and 5th percentile at 23 months
- Walking delayed until 18 months
- No family history of rickets
- Laboratory findings (see Table)
- Suspected diagnosis: probable vitamin D deficiency rickets; possible intestinal malabsorption; additional laboratory testing performed
- Recommended management: cholecalciferol and increased calorie intake
Nephrology evaluation
- Physical exam at 26 months: frontal bossing, waddling gait, prominent costochondral junctions, genu varus, bilateral tibial bowing; intercondylar distance 12.7 cm with ankles touching
- Height 3rd to 5th percentile (see Growth chart, A), weight <3rd percentile
- X-rays: metaphyseal flaring and cupping of the distal femoral and proximal and distal tibial and fibular metaphyses with varus bowing of the bilateral femurs, tibias, and fibula; and bilateral genu varum compatible with rickets (see X-rays)
- Laboratory findings (see Table)
Growth chart
FOOTNOTES
Patient growth evolution prior to and after CRYSVITA.
A: At 26 months, the patient was in the 3rd to 5th percentile for height.
B: At enrollment, the patient was in the 10th percentile for height.
C: While on CRYSVITA, the patient was between the 10th and 15th percentile for height.
†The reference percentiles on the graph are combined from the two clinical growth charts for girls 2-20 years of age provided by the Centers for Disease Control and Prevention.
Diagnosis and initial treatment
- Hypophosphatemic rickets, probable XLH
- Treatment: oral calcitriol and phosphate
Disease progression
Evaluation at academic center
- Physical exam at 37 months: wide-based gait, genu varus with intercondylar distance 2.5 cm; bilateral tibial bowing greater on the right than the left
- Height 10th percentile (see Growth chart, B)
- X-rays: mild metaphyseal widening at wrists
- Laboratory findings (see Table)
- Enrolled in CRYSVITA clinical trial
CRYSVITA treatment, 106 weeks
- Physical exam at 63 months: knees touching; mild tibial bowing on right
- Height 10th to 15th percentile (see Growth chart, C)
- X-rays: mild bowing of femurs; considerable improvement in varus (see X-rays)
- Laboratory findings: tests improved (see Table)
X-rays: evolution of rickets and lower limb deformity
Early evaluation
(26 months old)
Prior to CRYSVITA
(37 months old)
CRYSVITA 40 weeks
(47 months old)
CRYSVITA 64 weeks
(53 months old)
CRYSVITA 106 weeks
(63 months old)
Laboratory test results
| Results (age) | ||||||
|---|---|---|---|---|---|---|
| Test (reference rangea unit) | Early evaluation (24 months) |
Early evaluation (26 months) |
Prior to CRYSVITA (37 months) |
CRYSVITA 40 weeks (47 months) |
CRYSVITA 64 weeks (53 months) |
CRYSVITA 106 weeks (63 months) |
| Serum phosphorus (4.3-6.8 mg/dL) | 2.7 | 3.0 | 2.5 | 3.7 | 3.4 | 3.9 |
| TmP/GFR (4.0-5.2 mg/dL) | n/a | 2.5 | 2.15 | n/a | 2.79 | 3.91 |
| 25(OH)D (≥20 ng/mL) | 27 | n/a | 40 | n/a | 30 | n/a |
| ALP (156-369 U/L) | 487 | 502 | 528 | 369 | 232 | 295 |
| Serum calcium (9.2-10.5 mg/dL) | 9.9 | 9.8 | 9.3 | 9.2 | 8.9 | 9.4 |
| PTH (10-65 pg/mL) | 48 | n/a | 33 | 31 | 44 | n/a |
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FOOTNOTES
25(OH)D, 25-hydroxy vitamin D (calcifediol); ALP, alkaline phosphatase; PTH, parathyroid hormone; TmP/GFR, ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate.
aIndicates normal range, age, and sex matched. Note that normal range values may vary depending on reference dataset. The range in this table was provided by the treating physician.
Summary
- Patient presented with symptoms at 19 months and underwent several specialty evaluations before XLH diagnosis at 26 months
- Conventional therapy initiated; XLH symptoms continued to progress
- Patient enrolled in CRYSVITA clinical trial at 37 months
- After 106 weeks on CRYSVITA, patient demonstrated improvements in laboratory findings and lower limb deformity
*The information for this case study was provided courtesy of Dr. Anthony Portale, Division of Pediatric Nephrology, UCSF Benioff Children’s Hospital, San Francisco. This case study represents a real patient and is intended to be illustrative, not a recommendation for treatment or management. Not all patients will respond the same to CRYSVITA treatment. Results may vary. This case study does not claim to represent typical results.
Medical history*
Early evaluation
- Positive family history of X-linked hypophosphatemia (XLH); mother and older brother have XLH
- Early symptoms included leg bowing and delayed walking
Diagnosis and initial treatment
- XLH confirmed by genetic testing shortly after birth
- Conventional therapy with oral calcitriol and phosphate initiated at 30 months
Disease progression
XLH symptoms and associated complications
- Age 5.5: history of recurrent dental abscesses, hip pain, and abnormal gait; conventional therapy continued
- Physical exam: genu valgum (knock-knees), more pronounced on the right leg than left leg; height: 104.7 cm, between 3rd and 5th percentile (see Growth chart, A)
- Age 6.5: underwent epiphyseal stapling of the proximal femur bilaterally and right proximal tibia to correct deformities
- Age 8.8: transitioned from conventional therapy to CRYSVITA
- Physical exam: height between 3rd and 5th percentile (see Growth chart, B); no genu valgum; mild torsion of left tibia; renal ultrasound shows no evidence of nephrocalcinosis
- Laboratory findings (see Table)
- Enrolled in CRYSVITA clinical trial
CRYSVITA treatment, 3.8 years
- Physical exam at age 12: height at the 10th to 25th percentile (see Growth chart, C)
- Laboratory findings: tests improved (see Table)
- Radiology: rickets improved; mild residual widening and irregularity of physis of distal femur are observed (see X-rays); renal ultrasound shows no evidence of nephrocalcinosis
Growth chart
FOOTNOTES
Patient growth evolution prior to and after CRYSVITA.
A: Prior to 6 years, the patient’s height was at the 3rd to 5th percentile.
B: At enrollment in the CRYSVITA clinical trial, the patient’s height was at the 3rd to 5th percentile.
C: During CRYSVITA treatment, the patient’s height increased to the 10th to 25th percentile.
†The reference percentiles on the graph are combined from the two clinical growth charts for girls 2-20 years of age in Sets 1 and 2 of the clinical charts provided by the Centers for Disease Control and Prevention.
X-rays: evolution of rickets and lower limb deformity
Prior to CRYSVITA
(8 years old)
CRYSVITA 3.8 years
(12 years old)
Prior to CRYSVITA
(8 years old)
CRYSVITA 3.8 years
(12 years old)
Laboratory test results
| Results (age) | |||||
|---|---|---|---|---|---|
| Test (reference rangea unit) | Early evaluation (8.8 years) |
Prior to CRYSVITA (8.9 years) |
CRYSVITA 40 weeks (9.6 years) |
CRYSVITA 2 years (11 years) |
CRYSVITA 3.8 years (12 years) |
| Serum phosphorus (3.2-6.1 mg/dL) |
2.4 | 1.9 | 3.4 | 3.6 | 3.2 |
| TmP/GFR (4.0-5.2 mg/dL) |
n/a | 1.7 | 3.1 | 3.2 | 3.0 |
| 25(OH)D (20-50 ng/mL) |
n/a | 38 | n/a | 29 | 24 |
| ALP (156-369 U/L) |
492 | 490 | 538 | 404 | 300 |
| Serum calcium (8.8-10.3 mg/dL) |
9.5 | 9.7 | n/a | 9.7 | 9.4 |
| PTH (18-80 pg/mL) |
16 | 38 | 45 | 38 | 70 |
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FOOTNOTES
25(OH)D, 25-hydroxy vitamin D (calcifediol); ALP, alkaline phosphatase; PTH, parathyroid hormone; TmP/GFR, ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate.
aIndicates normal range, age, and sex matched. Note that normal range values may vary depending on reference dataset.
The range in this table was provided by the treating physician.
Summary
- Patient was diagnosed with XLH shortly after birth based on positive family history and genetic testing
- Conventional therapy was initiated at 30 months; XLH symptoms continued to progress
- Patient enrolled in CRYSVITA clinical trial at 8.8 years of age
- After approximately 4 years of treatment with CRYSVITA, patient demonstrated improvements in rickets severity, laboratory findings, and linear growth
*The information for this case study was provided courtesy of Dr. Anthony Portale, Division of Pediatric Nephrology, UCSF Benioff Children’s Hospital, San Francisco. This case study represents a real patient and is intended to be illustrative, not a recommendation for treatment or management. Not all patients will respond the same to CRYSVITA treatment. Results may vary. This case study does not claim to represent typical results.
Reference
- Clinical growth charts. Center for Disease Control and Prevention. Last reviewed June 16, 2017. Accessed December 20, 2021. https://www.cdc.gov/growthcharts/clinical_charts.htm
ADULT Patient Case Studies
See how CRYSVITA may help your patients
with XLH
Medical history*
During childhood
- Birth: positive family history of X-linked hypophosphatemia (XLH); father and paternal grandmother affected
- Early infancy and childhood symptoms included leg bowing and delayed growth
- X-rays: evidence of rickets
- Laboratory findings: hypophosphatemia
Diagnosis and initial treatment
- Diagnosed with XLH at birth
- Conventional therapy with oral calcitriol and phosphate initiated at 3 years of age
Disease progression
XLH symptoms and associated complications
- Age 7: conventional therapy continued
- Physical exam: mild genu varum (bowed legs) and mild tibial bowing; height below 3rd percentile (see Growth chart, A)
- Age 10: conventional therapy discontinued due to loss of medical insurance; lost to follow-up
- Age 12: oral calcitriol and phosphate resumed with intermittent adherence
- Physical exam: significant worsening of genu varum and tibial bowing; deceleration of growth: height below 3rd percentile (see Growth chart, B)
- X-rays: coxa vara, genu varum, femoral and mild tibial bowing, rachitic changes at knee and wrist (see X-rays)
- Laboratory findings (see Table)
- Age 12.5: underwent bilateral proximal tibial epiphysiodeses
- Age 18: worsening left leg pain
- X-rays: proximal tibial pseudofracture
- Age 19: persisting bilateral knee pain; abnormal gait; underwent proximal tibial osteotomy with realignment
- Physical exam: genu varum
- Age 23: enrolled in CRYSVITA clinical trial
CRYSVITA treatment
- Age 23.5: serum phosphorus improved; patient attempted to transfer care to adult specialist but could not find a provider with experience in the care of adults with XLH
- Age 24-25: transitioned care to an adult endocrinologist; married and expressed concern about risk of disease in future children; received genetic counseling
Growth chart
FOOTNOTES
Patient growth evolution.
A: At 7 years, the patient’s height was below the 3rd percentile.
B: At 13 years, the patient’s height continued to be below the 3rd percentile.
C: Final adult height remained below the 3rd percentile.
†The reference percentiles on the graph are combined from the two clinical growth charts for girls 2-20 years of age in Sets 1 and 2 of the clinical charts provided by the Centers for Disease Control and Prevention.
X-rays: rickets
Laboratory test results
| Test (reference rangea unit) |
Results (age) | |||
|---|---|---|---|---|
| Conventional therapy (12 years) |
Conventional therapy (23 years) |
CRYSVITA (23.5 years) |
CRYSVITA (25 years) |
|
| Serum phosphorus (2.5-4.5 mg/dL) |
2.0 | 1.9 | 3.1 | 2.9 |
| TmP/GFR (2.5-4.2 mg/dL) |
n/a | 1.5 | 2.7 | n/a |
| 25(OH)D (20-50 ng/mL) |
n/a | 28 | 25 | n/a |
| Serum calcium (8.6-10.2 mg/dL) |
9.7 | 8.9 | 8.7 | 9.3 |
| PTH (14-72 pg/mL) |
57 | 49 | n/a | n/a |
FOOTNOTES
25(OH)D, 25-hydroxy vitamin D (calcifediol); PTH, parathyroid hormone; TmP/GFR, ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate.
aIndicates normal range, age, and sex matched. Note that normal range values may vary depending on reference dataset.
The range in this table was provided by the reference laboratory.
Summary
- Patient was diagnosed with XLH at birth based on family history
- Conventional therapy was initiated at 3 years of age; XLH symptoms continued to progress
- CRYSVITA was initiated at age 23; serum phosphorus values improved
- Patient experienced difficulty finding an experienced adult specialist in order to transition care from pediatric providers
*The information for this case study was provided courtesy of Dr. Anthony Portale, Director of the Pediatric Dialysis Program, UCSF Benioff Children’s Hospital, San Francisco. This case study represents a real patient and is intended to be illustrative, not a recommendation for treatment or management. Not all patients will respond the same to CRYSVITA treatment. Results may vary. This case study does not claim to represent typical results.
Medical history*
During childhood
- Age 5: evidence of rickets in wrists and knees along with delayed skeletal maturation; sister and father with known history of X-linked hypophosphatemia (XLH)
- Diagnosed with XLH based on clinical and biochemical findings and family history
- Initiated oral calcitriol and phosphate
- Renal ultrasound indicated nephrocalcinosis; serum phosphorus was 2.4 (reference range 2.5 to 4.5 mg/dL); alkaline phosphatase was 538 U/L (reference range 100 to 300 U/L)
- Age 7: radiographic evidence of rickets in lower limbs (see X-ray 1)
- Age 8: stiffness and bone pain documented in pediatric records
- Age 9 to 18: treatment for depression
- Age 15 to 18: underwent bilateral hip surgery due to bilateral impingements and tibial osteotomy
- No history of recombinant growth hormone use
- Fracture history includes stress fracture of right femur, right ankle fracture, and left wrist fracture
Transition to adult metabolic clinic, exam at age 25
- Previously cared for in the pediatric endocrine clinic
- Physical exam
- Height, 4’11” (both mother and father, 5’2”)
- No evidence of scoliosis
- Reported stiffness, which made it difficult to get up from sitting positions or to stand for prolonged periods of time
- Reported disabling bone and muscle pain; ongoing symptoms of childhood rickets complicated by depression; history of opiate dependence
- Adherent to medical management with renal ultrasounds and 24-hour urine collections every 6 months
X-rays
X-Ray 1: Rickets
X-Ray 2: Enthesopathy
X-Ray 3: Right Knee Discomfort
Diagnosis and initial treatment
- Confirmed XLH diagnosis
- Treatment: continue oral calcitriol and phosphate
- Referral to integrative medicine
Disease progression
Integrative medicine evaluation
- Greatest patient-reported health concern: lower extremity pain (bilateral hips, knees, and ankles), which was experienced since early teens
- Due to pain, transitioned jobs from a bedside nurse position into an administrative desk position
- Reported anxiety and depression; expressed concerns with taking too many medications at a young age
- Previously hospitalized for attempted suicide
X-ray evaluation at age 26 (see X-ray 2)
- Bilateral calcaneal enthesophytes; left Achilles enthesophyte previously broken
- Small bilateral Haglund bumps with mild bilateral retrocalcaneal bursitis
Metabolic clinic follow-up evaluation at age 27
- Maintained adherence to prescribed XLH treatment; no change in dosage
- Reported recent root canal for an abscess
- Reported persistent pain
- Recent Achilles tendon tear
- Developed lower back pain
- Developed pain in the anteromedial aspect of the right knee with prolonged walking, sit/stand transition, or using steps (see X-ray 2)
- Referred to physical medicine and rehabilitation
- Laboratory findings (see Table)
- Initiated CRYSVITA treatment
CRYSVITA treatment, 21 weeks
- Patient reported resolution of stiffness and a return to work
- Laboratory findings: tests improved (see Table)
- Adverse reactions included mild injection site reactions (ISRs) and restless legs syndrome (RLS)
- ISRs were treated with topical antihistamine medication
- RLS resolved after 3 months
Laboratory test results
| Test (reference rangea unit) | Results (age) | |
|---|---|---|
| Prior to CRYSVITA (27 years) |
CRYSVITA 21 weeks (27 years) |
|
| Serum phosphorus (2.3-4.7 mg/dL) | 1.2 | 3.1 |
| 1,25 (OH)2 (20-79 ng/mL) | 31.4 | 73 |
| 25(OH)D (25-80 ng/mL) | 36 | 30 |
| BSAP (4.5-16.9 mcg/L) | 21.3 | 19.2 |
| PTH (16-88 pg/mL) | 54 | 43 |
| Creatinine (0.57-1.11 mg/dL) | - | 0.73 |
FOOTNOTES
1,25 (OH)2, 1,25 25-hydroxy vitamin D; 25(OH)D, 25-hydroxy vitamin D (calcifediol); BSAP, bone-specific alkaline phosphatase, also known as BAP; PTH, parathyroid hormone.
aIndicates normal range, age, and sex matched. Note that normal range values may vary depending on reference dataset. The range in this table was provided by the treating physician.
Summary
- At age 5, patient was diagnosed with XLH; was compliant with conventional therapy of oral phosphate and calcitriol
- XLH symptoms progressed from diagnosis: history of fractures, stiffness, pain, and impaired physical function
- Disease progression in adulthood was managed by multiple specialties including endocrinology, integrative medicine, and physical medicine and rehabilitation
- At age 27, patient initiated CRYSVITA; after 5 months demonstrated improvements in laboratory findings and joint stiffness
- Adverse reactions associated with CRYSVITA treatment included ISRs and RLS; ISRs were treated with topical antihistamine, and RLS resolved after 3 months
*The information for this case study was provided courtesy of Dr. Kathyryn McCrystal Dahir, Professor of Medicine, Department of Endocrinology, Vanderbilt University Medical Center, Nashville. This case study represents a real patient and is intended to be illustrative, not a recommendation for treatment or management. Not all patients will respond the same to CRYSVITA treatment. Results may vary. This case study does not claim to represent typical results.
Medical history*
During childhood
- Age 2: diagnosed with X-linked hypophosphatemia (XLH) as a toddler
- Initiated oral phosphate and calcitriol and was compliant
- Age 13: XLH diagnosis was confirmed by genetic testing
Family history
- Mother and maternal grandmother had XLH
XLH symptoms and associated complications in adulthood
- Chiari malformation requiring two corrective surgeries
- Chronic ankle pain and swelling in joints
- Gait abnormalities
- Sustained pelvic fracture during childbirth
- Age 33: discontinued oral phosphate and calcitriol
Evaluation prior to CRYSVITA
- Age 35: presented to adult endocrinology with bowing of upper and lower extremities and joint stiffness in hips, knees, and ankles
- Physical exam
- Height, 5’2”
- Required the use of assistive walking device (cane) for long distances and handicap tags due to mobility challenges
- Tinnitus in right ear
- Calcifications noted on prior renal ultrasound
- Laboratory findings (see Table)
- Physical therapy evaluation
- Required assistance to rise from seated to standing position
- Tight hip flexors; limited range of motion in hips
- X-rays
- Prominent enthesophytes associated with the calcaneus bilaterally as well as ankle and midfoot arthritis; slight bowing seen bilaterally in lower legs (see X-ray 1)
- Hypertrophic bone formation occurring at the hip articulation and trochanters; sclerosis at the sacroiliac joints; slight bilateral bowing of femurs (see X-ray 2)
- Bowing deformity at each femur and degenerative changes of the knees including bilateral articular surface irregularities of the femoral condyles (see X-ray 3)
- Bilateral bowing of femurs, tibias, and fibulas; bones diffusely demineralized and bilateral narrowing of joint space compartment also noted (see X-ray 4)
X-rays (at 35 years old)
X-Ray 1: Feet
X-Ray 2: Hips and Femurs
X-Ray 3: Knees
X-Ray 4: Knees
Diagnosis and initial treatment
- XLH diagnosis reconfirmed
- Treatment: CRYSVITA
Disease progression
CRYSVITA treatment, 35 weeks
- Age 36: initiated CRYSVITA and over time reported progressive improvement in joint stiffness
- After 10 weeks: CRYSVITA dose reduced after a 30-pound intentional weight loss due to diet and increased physical activity
- Reported adverse events
- Myalgias and fatigue, left knee swelling and pain during the first 3 months
- Adverse events managed with over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid pain medication; resolved with subsequent CRYSVITA injections
- No restless legs symptoms or injection site reactions were reported
- Laboratory findings: biochemical improvements after 35 weeks (see Table)
Laboratory test results
| Test (reference rangea unit) | Results (age) | |
|---|---|---|
| Early evalution (35 years) |
CRYSVITA 35 weeks (37 years) |
|
| Serum phosphorus (2.3-4.7 mg/dL) | 1.6 | 2.6 |
| 1,25 (OH)2 (20-80 ng/mL) | 40.3 | - |
| 25(OH)D (25-80 ng/mL) | 35 | 60.6 |
| BSAP (4.5-16.9 mcg/L) | 25 | 19.1 |
| PTH (16-88 pg/mL) | 55 | 52 |
| Creatinine (0.57-1.11 mg/dL) | 0.74 | 0.70 |
FOOTNOTES
1,25 (OH)2, 1,25 25-hydroxy vitamin D; 25(OH)D, 25-hydroxy vitamin D (calcifediol); BSAP, bone-specific alkaline phosphatase, also known as BAP; PTH, parathyroid hormone.
aIndicates normal range, age, and sex matched. Note that normal range values may vary depending on reference dataset. The range in this table was provided by the treating physician.
Summary
- Patient was diagnosed with XLH as a toddler and suffered from XLH-associated symptoms throughout adulthood, including fractures, joint stiffness, pain, and diminished physical function
- At age 36, CRYSVITA was initiated and after nearly a year, patient demonstrated improvements in serum phosphorus levels and joint stiffness
- Adverse reactions reported during treatment included myalgia, fatigue, and left knee pain and swelling, which resolved within 3 months of treatment
*The information for this case study was provided courtesy of Dr. Kathyryn McCrystal Dahir, Professor of Medicine, Department of Endocrinology, Vanderbilt University Medical Center, Nashville. This case study represents a real patient and is intended to be illustrative, not a recommendation for treatment or management. Not all patients will respond the same to CRYSVITA treatment. Results may vary. This case study does not claim to represent typical results.
Reference
- Clinical growth charts. Centers for Disease Control and Prevention website. Last reviewed June 16, 2017. Accessed September 24, 2020. https://www.cdc.gov/growthcharts/clinical_charts.htm
Laboratory test results
| Test (reference rangea unit) | Results (age) | |||
|---|---|---|---|---|
| Conventional therapy (12 years) |
Conventional therapy (23 years) |
CRYSVITA (23.5 years) |
CRYSVITA (25 years) |
|
| Serum phosphorus (2.5-4.5 mg/dL) |
2.0 | 1.9 | 3.1 | 2.9 |
| TmP/GFR (2.5-4.2 mg/dL) |
n/a | 1.5 | 2.7 | n/a |
| 25(OH)D (20-50 ng/mL) |
n/a | 28 | 25 | n/a |
| Serum calcium (8.6-10.2 mg/dL) |
9.7 | 8.9 | 8.7 | 9.3 |
| PTH (14-72 pg/mL) |
57 | 49 | n/a | n/a |
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×
Growth Chart
×
X-Rays: Rickets
At 12 years old: coxa vara, genu varum, femoral and mild tibial bowing, rachitic changes at knee and wrist (arrows).
×
X-Ray 2: Rickets
×
Laboratory test results
| Test (reference rangea unit) | Results (age) | |
|---|---|---|
| Prior to CRYSVITA (27 years) |
CRYSVITA 21 weeks (27 years) |
|
| Serum phosphorus (2.3-4.7 mg/dL) | 1.2 | 3.1 |
| 1,25 (OH)2 (20-79 ng/mL) | 31.4 | 73 |
| 25(OH)D (25-80 ng/mL) | 36 | 30 |
| BSAP (4.5-16.9 mcg/L) | 21.3 | 19.2 |
| PTH (16-88 pg/mL) | 54 | 43 |
| Creatinine (0.57-1.11 mg/dL) | - | 0.73 |
×
X-Ray 1: Rickets
×
X-Ray 2: Enthesopathy
At 26 years old: bilateral calcaneal enthesophytes; previously broken left Achilles enthesophyte; small bilateral Haglund bumps with mild bilateral retrocalcaneal bursitis.
×
X-Ray 3: Right Knee Discomfort
At 27 years old: significant discomfort in the anteromedial aspect of the right knee with use. Proximal tibial osteotomy performed when patient was a teenager.
×
Laboratory test results
| Test (reference rangea unit) | Results (age) | |
|---|---|---|
| Early evalution (35 years) |
CRYSVITA 35 weeks (37 years) |
|
| Serum phosphorus (2.3-4.7 mg/dL) | 1.6 | 2.6 |
| 1,25 (OH)2 (20-80 ng/mL) | 40.3 | - |
| 25(OH)D (25-80 ng/mL) | 35 | 60.6 |
| BSAP (4.5-16.9 mcg/L) | 25 | 19.1 |
| PTH (16-88 pg/mL) | 55 | 52 |
| Creatinine (0.57-1.11 mg/dL) | 0.74 | 0.70 |
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X-Ray 1: Feet
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X-Ray 2: Hips and Femurs
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X-Ray 3: Knees
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X-Ray 4: Knees
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Growth Chart
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Laboratory test results
| Test (reference rangea unit) | Results (age) | |||
|---|---|---|---|---|
| Early evaluation (24.5 months) |
Prior to CRYSVITA (31 months) |
CRYSVITA 40 weeks (40 months) |
CRYSVITA 64 weeks (46 months) |
|
| Serum phosphorus (4.3-6.8 mg/dL) | 2.9 | 2.9 | 3.7 | 4 |
| TmP/GFR (4.0-5.2 mg/dL) | n/a | 2.8 | 3.7 | 4 |
| 25(OH)D (≥20 ng/mL) | 26 | 24 | 36 | 26 |
| ALP (156-369 U/L) | 636 | 459 | 283 | 299 |
| Serum calcium (9.2-10.5 mg/dL) | 9.4 | 9.5 | 9.6 | 9.6 |
| PTH (10-65 pg/mL) | 56 | 20 | 36 | 23 |
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X-RAYS: Evolution of Rickets and Lower Limb Deformity
Prior to CRYSVITA
(29 months old)
CRYSVITA 40 weeks
(40 months old)
CRYSVITA 64 weeks
(46 months old)
Cupping and fraying of growth plates, marked bowing.
Prior to CRYSVITA
(29 months old)
CRYSVITA 40 weeks
(40 months old)
CRYSVITA 64 weeks
(46 months old)
Resolved cupping and fraying of metaphysis of radius and ulna; improved fraying of femoral metaphysis; decreased widening of femoral growth plate.
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Growth Chart
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Laboratory test results
| Results (age) | ||||||
|---|---|---|---|---|---|---|
| Test (reference rangea unit) | Early evaluation (24 months) |
Early evaluation (26 months) |
Prior to CRYSVITA (37 months) |
CRYSVITA 40 weeks (47 months) |
CRYSVITA 64 weeks (53 months) |
CRYSVITA 106 weeks (63 months) |
| Serum phosphorus (4.3-6.8 mg/dL) | 2.7 | 3.0 | 2.5 | 3.7 | 3.4 | 3.9 |
| TmP/GFR (4.0-5.2 mg/dL) | n/a | 2.5 | 2.15 | n/a | 2.79 | 3.91 |
| 25(OH)D (≥20 ng/mL) | 27 | n/a | 40 | n/a | 30 | n/a |
| ALP (156-369 U/L) | 487 | 502 | 528 | 369 | 232 | 295 |
| Serum calcium (9.2-10.5 mg/dL) | 9.9 | 9.8 | 9.3 | 9.2 | 8.9 | 9.4 |
| PTH (10-65 pg/mL) | 48 | n/a | 33 | 31 | 44 | n/a |
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X-rays: Evolution of Rickets and Lower Limb Deformity
Early evaluation
(26 months old)
Prior to CRYSVITA
(37 months old)
CRYSVITA 40 weeks
(47 months old)
CRYSVITA 64 weeks
(53 months old)
CRYSVITA 106 weeks
(63 months old)
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Laboratory test results
| Results (age) | |||||
|---|---|---|---|---|---|
| Test (reference rangea unit) | Early evaluation (8.8 years) |
Prior to CRYSVITA (8.9 years) |
CRYSVITA 40 weeks (9.6 years) |
CRYSVITA 2 years (11 years) |
CRYSVITA 3.8 years (12 years) |
| Serum phosphorus (3.2-6.1 mg/dL) |
2.4 | 1.9 | 3.4 | 3.6 | 3.2 |
| TmP/GFR (4.0-5.2 mg/dL) |
n/a | 1.7 | 3.1 | 3.2 | 3.0 |
| 25(OH)D (20-50 ng/mL) |
n/a | 38 | n/a | 29 | 24 |
| ALP (156-369 U/L) |
492 | 490 | 538 | 404 | 300 |
| Serum calcium (8.8-10.3 mg/dL) |
9.5 | 9.7 | n/a | 9.7 | 9.4 |
| PTH (18-80 pg/mL) |
16 | 38 | 45 | 38 | 70 |
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Growth Chart
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X-rays: Evolution of Rickets and Lower Limb Deformity
Prior to CRYSVITA
(8 years old)
Active rickets at knee.
CRYSVITA 3.8 years
(12 years old)
Mild widening of physis of distal femur.
Prior to CRYSVITA
(8 years old)
Femoral bowing, coxa vara.
CRYSVITA 3.8 years
(12 years old)
Persistent femoral bowing.
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