Vosoritide for Short Stature in Turner Syndrome

Eligibility Criteria

• 1. Parent(s) or guardian(s) are willing and able to provide written, signed informed consent after the nature of the study has been explained and prior to performance of any research-related procedure. Also, subjects under the age of 18 are willing and able to provide assent (if required) after the nature of the study has been explained and prior to performance of any research-related procedure.
• 2. Stated willingness to comply with all study procedures and availability for the duration of the study
• 3. Age \>3 years 0 days AND \<10 years 364 days
• 4. Pre-pubertal defined as Tanner Stage 1 breasts in females.
• 5. Patient height \<-2 SDS. All height SDS values are calculated using the CDC growth charts/data tables.
• 6. Patients must have a confirmed diagnosis of Turner Syndrome based on a karyotype with a minimum of 30 cells or on a chromosomal microarray. Subjects with Turner Syndrome mosaicism (such as a 46,XX/45,X karyotype) must have a minimum of 10% mosaicism of 45,X cell line in order to participate in the study.
• 7. Subjects must either be naïve to growth hormone or have a poor response to growth hormone therapy defined as either:
• 1. Subjects completed at least one year of treatment with GH and first year height velocity (HV) below -1 SD according to the National Cooperative Growth Study TS 1st year response to growth hormone height velocity curve.
• 2. Subjects receiving GH for more than a year with AGV in the last 6 months \< 50%ile for US girls for age/sex). Subjects meeting this criterion are no longer showing catch up growth and may benefit from an alternative form of therapy.
• 1. Growth plate fusion - Defined as a bone age via the Greulich and Pyle method of 13 years. These patients have limited remaining growth potential.
• 2. Concomitant treatment with growth hormone or recombinant insulin-like growth factor-1 (IGF-1). Patients may have been previously treated with growth hormone or IGF-1 therapy. If the patient is currently on one of these therapies, they will be required to discontinue at least 1 week prior to the screening visit. That decision will be deferred to their treating clinical endocrinologists in conjunction with the patient's guardians. We anticipate that only patients who are having a poor response to their therapy will be interested in enrolling in the current study as there is no rationale for a patient who is receiving growth hormone therapy and having a positive response to enroll in the current study.
• 3. Prior or concomitant treatment with any form of estrogen, gonadotropin-releasing hormone (GnRH) analog, aromatase inhibitor or oxandrolone
• 4. History of any type of malignancy
• 5. Subjects known to have Y-chromosome material unless they have undergone gonadectomy and have fully external female genitalia
• 6. Chronic medical condition known to affect growth including but not limited to:
• 7. Malnutrition - Defined as a BMI \<5th percentile (CDC growth charts)
• 8. Any clinically significant abnormality on screening tests as determined by the principal investigator. Abnormal screening labs may be repeated up to 3 months after the screening visit. If those labs are normal on repeat, the subject may proceed into the trial.
• 9. Known or suspected allergy to trial medication, excipients, or related products
• 10. The receipt of any investigational drug within 90 days prior to this trial