A Study to Learn if Recombinant Human Parathyroid Hormone [rhPTH(1-84)] Can Improve Symptoms and Metabolic Control in Adults With Hypoparathyroidism (BALANCE)

Has an understanding, ability, and willingness to fully comply with study procedures and restrictions.

Is able to voluntarily provide a signed and dated informed consent form before any study-related procedures are performed.

Is an adult male or female 18 to 85 years of age, inclusive.

In participants 18-25 years of age, has radiological evidence of epiphyseal closure based on bone age X-ray (single posteroanterior X-ray of left wrist and hand) before randomization.

Has chronic hypoparathyroidism with onset 12 months or more before screening. The diagnosis of hypoparathyroidism is established based on hypocalcemia in the setting of inappropriately low serum PTH levels.

During the Week -3 screening visit, the participant reports by history at least 2 of the following symptoms related to hypoparathyroidism occurring within the 2 weeks before Week -3 visit: muscle cramps, muscle spasms or twitching, tingling, numbness, heaviness in arms or legs, physical fatigue, or slowed or confused thinking (brain fog).

The participant must have a Hypoparathyroidism Symptom Diary (HPT-SD) symptom subscale Sum Score of greater than or equal to (\>=) 10 during the 14-day period immediately prior to the baseline (Week 0) visit (Day -14 to Day -1). In addition, the participant must have at least 4 HPT-SD diaries completed in the first 7 day period and at least 4 HPT-SD diaries completed in second 7 day period.

Must be treated with active vitamin D (calcitriol or alfacalcidol) alone or in conjunction with calcium supplements for at least 4 months prior to the screening visit.

1. The participant must be taking \>= 0.5 microgram (mcg)/day of calcitriol or \>=1.0 mcg/day of alfacalcidol.

2. If the participant is treated with a lower dose of active vitamin D the participant must also be taking calcium supplements of at least 800 milligrams per day (mg/day) of elemental calcium.

Has serum thyroid-stimulating hormone (TSH) results within normal laboratory limits at screening for all participants not receiving thyroid hormone replacement therapy. For participants on thyroid hormone replacement therapy, the thyroid hormone dose must have been stable for at least 4 weeks before screening, and serum TSH level must be within the central laboratory normal range. A serum TSH level below the lower limit of the normal range but not undetectable in participant treated with thyroid hormone may be allowed if there is no anticipated need for a change in thyroid hormone dose during the trial.

Has serum 25-hydroxyvitamin D levels \>=50 nmol/L (nanomoles per liter) (20 nanograms per milliliter \[ng/mL\]) and less than (\<) 1.5 times the upper limit of normal (ULN) for the central laboratory normal range.

Has estimated glomerular filtration rate (eGFR) greater than (\>) 30 milliliter per minute per 1.73 square meters (ml/min/1.73m\^2).

Prior to randomization, is able to perform daily SC self-injections of study medication (or have a designee perform injection) via a multidose injection pen into the thigh.

Willing to use oral active vitamin D and calcium supplements provided for the study unless directed to remain on the supplements used prior to enrollment in the current study by the investigator after consultation with the medical monitor.

With regard to female participants: women who are postmenopausal (12 consecutive months of spontaneous amenorrhea and age \>= 51 years) and women who are surgically sterilized can be enrolled. Women of childbearing potential must have a negative pregnancy test at randomization and be willing to comply with any applicable contraceptive requirements of the protocol and pregnancy testing for the duration of the study.

What this study is about