Ultragenyx Pharmaceutical Inc. ( RARE ) shares are down on Thursday as the company reported data from its Phase 3 study of DTX301, a gene therapy for ornithine transcarbamylase (OTC) deficiency.

• Ultragenyx Pharmaceutical ( RARE ) shares are sliding. Why is RARE stock dropping?

OTC deficiency is an inherited disorder that causes ammonia to accumulate in the blood. OTC is one of six enzymes that play a role in the breakdown and removal of nitrogen from the body, a process known as the urea cycle. The lack of the OTC enzyme results in excessive accumulation of nitrogen, in the form of ammonia (hyperammonemia), in the blood.

Ultragenyx Reveals Rare Disease Trial Data

The 36-week data from the phase 3 study of DTX301 showed promising results, with a significant increase in urinary orotic acid levels.

At week 36, DTX301-treated patients (n=18) demonstrated a 18% reduction in 24-hour plasma ammonia compared to placebo (n=19) and maintained average ammonia AUC0-24 in the normal range through week 36.

Eight of nine patients with abnormal ammonia at baseline, despite optimal current drug treatment and diet restriction, reached normal ammonia levels rapidly, which were generally maintained during this treatment period.

Baseline 24-hour ammonia AUC levels were normal in 50% of DTX301-treated patients and 68% of placebo patients, who were all on current care of scavenger medications and strict dietary control of protein intake.

Patients treated with DTX301 (n=18) experienced a rapid reduction in 24-hour ammonia by week 6 and were decreased by 18% compared to placebo (n=19) at Week 36.

Ammonia was generally maintained in normal range in treated patients despite their mean 27% reduction in ammonia scavenger medications at week 36 (n=18) and an approximately 13% increase in protein intake relative to no change in placebo (n=19).

Safety Profile

DTX301 was well tolerated with an acceptable safety profile, consistent with prior phase 1/2 safety data.

The most common treatment-emergent adverse events were mild to moderate transient hepatic reactions managed with steroids.

One serious adverse event (SAE) of acute hepatitis was assessed as treatment-related and resolved with steroids.

What Comes Next For Ultragenyx

The study is continuing to its second primary endpoint, the reduction in treatment burden through 64 weeks of follow-up.

The company expects data in the first half of 2027.

Ultragenyx Pharmaceutical Technical Analysis

Currently, Ultragenyx is trading 3.7% below its 20-day simple moving average (SMA) and 24.8% below its 100-day SMA, indicating bearish momentum in the short to medium term.

Over the past 12 months, shares have decreased by 46.87%, and they are positioned closer to their 52-week lows.

The RSI is at 43.32, which is considered neutral territory, while the MACD shows a value of -0.5147, with the signal line at -0.6510, indicating bullish momentum as the MACD is above the signal line.

The combination of neutral RSI and bullish MACD suggests mixed momentum, reflecting uncertainty in the stock’s performance.

Key Resistance: $25.50

Key Support: $19.50

Analyst Consensus & Recent Actions: The stock carries a Buy Rating with an average price target of $71.45. Recent analyst moves include:

Canaccord Genuity: Buy (Lowers target to $79 on Feb. 18)

Evercore ISI Group: Outperform (Lowers target to $34 on Feb. 18)

Top ETF Exposure

Tema Heart & Health ETF ( HRTS ) : 3.25% Weight

RARE Stock Price Activity: Ultragenyx Pharmaceutical ( RARE ) shares were down 3.02% at $21.54 at the time of publication on Thursday, according to Benzinga Pro data.

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