Upacicalcet meets primary endpoint in two Phase 3 trials for dialysis patients

Overview

Updated 1 hour ago

Nearly all patients on dialysis develop secondary hyperparathyroidism, a condition in which parathyroid hormone climbs out of control and raises the risk of bone fractures and heart disease. On October 23, Pathalys Pharma presented Phase 3 data showing its intravenous drug upacicalcet reduced PTH by at least 30% in 42% of treated patients, versus 17% on placebo, in each of two identical trials.

The results, published the same day in the Journal of the American Society of Nephrology, set up an FDA submission. Upacicalcet has been sold in Japan since 2021. An approval would give US dialysis patients the first new calcimimetic since 2017.

Why it matters

If the FDA approves it, upacicalcet would be the first new IV calcimimetic for US dialysis patients in nearly a decade.

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Key Indicators

42.1%

PATH-1 primary endpoint rate

Patients on upacicalcet cutting PTH by 30% or more, versus 16.8% on placebo.

43.5%

PATH-2 primary endpoint rate

Same endpoint in the second trial, versus 17.4% on placebo.

768

Patients across both trials

Randomized 2:1 to upacicalcet or placebo after each dialysis session for 27 weeks.

23%

Asymptomatic hypocalcemia, PATH-1

The most common side effect, versus 8% on placebo; symptomatic cases were rare.

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Jessica Kendrick, MD, MPH

Professor of renal medicine, University of Colorado; primary investigator for PATH trials

Presented the Phase 3 findings at ASN Kidney Week 2026

Bastian Dehmel, MD

Chief Medical Officer, Pathalys Pharma

Leads clinical development for upacicalcet

Organizations Involved

Pathalys Pharma

Private biopharmaceutical company

Developer of upacicalcet; planning FDA submission

Private US biopharmaceutical company developing upacicalcet for chronic kidney disease.

American Society of Nephrology

Medical society

Hosted Kidney Week 2026 and published trial results in its journal

Medical society that hosted Kidney Week 2026 and publishes the Journal of the American Society of Nephrology.

Timeline

2021 October 2026

3 events Latest: 2 days ago

October 2026
PATH-1 and PATH-2 results presented
Latest Clinical Results

Both pivotal US trials meet primary and key secondary endpoints; papers published in JASN.
2 days ago
2023
Japanese Phase 3 data published
Publication

A 24-week placebo-controlled trial in Japanese dialysis patients shows PTH reductions.
2023
2021
Japan approves upacicalcet
Regulatory Approval

Japanese regulators clear upacicalcet for SHPT in dialysis patients.
2021

Scenarios

FDA approves upacicalcet for SHPT

Likely Resolves by End of 2028

Discussed by: Pathalys leadership and trial investigators

Pathalys files a New Drug Application with the FDA and the agency approves upacicalcet for secondary hyperparathyroidism in hemodialysis patients, making it the first new calcimimetic in nearly a decade. The two positive trials, with similar effect sizes and tolerable safety, support a standard review.

FDA issues Complete Response Letter, delaying approval

Possible Resolves by End of 2028

Discussed by: FDA precedent and trial safety data

The FDA asks for more data before deciding — whether on hypocalcemia, which reached 23% versus 8% on placebo in PATH-1, or on manufacturing. Upacicalcet is already approved in Japan, but the agency has required additional US trials for other calcimimetics when safety questions emerged.

Pathalys is acquired or partners on upacicalcet

Uncertain Resolves by End of 2027

Discussed by: Biotech industry observers

A larger pharmaceutical company acquires Pathalys or licenses US rights to upacicalcet after the Phase 3 success. Single-asset companies with positive pivotal data often attract buyers seeking to add a CKD product to their portfolios, which would change who carries the drug through approval and launch.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

March 2004

Cinacalcet (Sensipar), 2004

Amgen's cinacalcet became the first calcimimetic approved by the FDA. The oral pill lowered PTH in dialysis patients but its gastrointestinal side effects and daily dosing limited how widely it was used.

Then

Cinacalcet became the standard medical treatment for SHPT.

Now

Its patent has since expired and generics are available, so new entrants must compete on dosing and safety rather than novelty.

Why this matters now

Upacicalcet enters a market where the oral calcimimetic is generic and cheap, so its value rests on the IV route and side-effect profile.

February 2017

Etelcalcetide (Parsabiv), 2017

Amgen's etelcalcetide, approved in 2017, was the first intravenous calcimimetic, dosed three times weekly after dialysis. It proved the injectable approach works but carried its own hypocalcemia and gastrointestinal risks.

Then

Etelcalcetide offered an alternative for patients who could not tolerate oral cinacalcet.

Now

It set the precedent that IV calcimimetics are viable for this population, but also established expectations about managing hypocalcemia.

Why this matters now

Upacicalcet follows the same IV model nearly a decade later, aiming to improve on the established safety profile.