HOW TO USE THIS SNAPSHOT
The information provided in Snapshots highlights who participated in the key clinical trials that supported the original FDA approval of this drug, and whether there were differences among sex, race, age, and ethnic groups. The “MORE INFO” bar shows more detailed, technical content for each section. The Snapshot is intended as one tool for consumers to use when discussing the risks and benefits of the drugs.

LIMITATIONS OF THIS SNAPSHOT
Do not rely on Snapshots to make decisions regarding medical care. Always speak to your healthcare provider about the benefits and risks of a drug.

Some of the information in this Snapshot is for presentation purposes and does not represent the approved conditions of use of this drug. Refer to the DAWNZERA Prescribing Information for all the approved conditions of use of this drug (e.g., indication(s), population(s), dosing regimen(s), safety information).

Snapshots are limited to the information available at the time of the original approval of the drug and do not provide information on who participated in clinical trials that supported later approvals for additional uses of the drug (if applicable).

DAWNZERA (donidalorsen) 
dawn-ZAIR-ah
Ionis Pharmaceuticals, Inc.
Approval date: August 21, 2025

DRUG TRIALS SNAPSHOT SUMMARY:

What is the drug for?

DAWNZERA is a prekallikrein-directed antisense oligonucleotide indicated for prophylaxis to prevent attacks of hereditary angioedema (HAE) in adult and pediatric patients 12 years of age and older.

How is this drug used?

DAWNZERA is a subcutaneous injection that is taken every four or eight weeks.

Who participated in the clinical trials?

The FDA approved DAWNZERA based on evidence from one clinical trial of 90 patients with type I and type II HAE. The trial was conducted at 39 sites in 13 countries in Belgium, Bulgaria, France, Germany, Italy, Netherlands, Poland, Spain, United States, Canada, United Kingdom, Israel, and Turkey. A total of 18 subjects were enrolled at sites in the United States.

How were the trials designed?

DAWNZERA was evaluated in a clinical trial of 90 adult and pediatric patients 12 years of age and older with type I and type II HAE. The trial was a 24-week multicenter, randomized, double-blind, placebo-controlled trial (OASIS-HAE), in which patients received subcutaneous doses of DAWNZERA 80 mg every four weeks (n=45), DAWNZERA 80 mg every eight weeks (n=23), or matching placebo (n=22). The primary endpoint for OASIS-HAE was the HAE attack rate (number of investigator-confirmed HAE attacks per four weeks) from Week 0 to Week 24.

How were the trials designed?

The efficacy and safety of DAWNZERA 80 mg every four weeks or every eight weeks were evaluated in a 24-week multicenter, randomized, double-blind, placebo-controlled trial (OASIS-HAE), in which adults and pediatric patients aged 12 years of age and older with HAE received subcutaneous doses of DAWNZERA 80 mg every four weeks (n=45), DAWNZERA 80 mg every eight weeks (n=23), or matching placebo (n=22). The trial included a two-month run-in period during which patients had to demonstrate two or more acute HAE attacks. Eligible patients were randomized in a 3:1 ratio to receive DAWNZERA or placebo every four or eight weeks over a six-month treatment period. The primary endpoint for OASIS-HAE was the HAE attack rate (number of investigator-confirmed HAE attacks per four weeks) from Week 0 to Week 24.

DEMOGRAPHICS SNAPSHOT

Figure 1 shows how many male and female patients were enrolled in the clinical trial used to evaluate the efficacy of DAWNZERA.

Figure 1. Baseline Demographics by Sex, Safety Population

Source: Source: Adapted from FDA Review

Figure 2 shows how many patients by race were enrolled in the clinical trial used to evaluate the efficacy of DAWNZERA.

Figure 2. Baseline Demographics by Race, Safety Population

Source: Adapted from FDA Review 
* Other includes: American Indian or Alaska Native (3 patients), multiple races (1 patient), and other race (1 patient).

Figure 3 shows how many patients by age were enrolled in the clinical trial used to evaluate the efficacy of DAWNZERA.

Figure 3. Baseline Demographics by Age, Safety Population

Source: Adapted from FDA Review

Figure 4 shows how many patients by ethnicity were enrolled in the clinical trial used to evaluate the efficacy of DAWNZERA.

Figure 4. Baseline Demographics by Ethnicity, Safety Population

Source: Adapted from FDA Review

Who participated in the trials?

Table 1. Baseline Demographics of Efficacy Trial

Characteristic

DAWNZERA

80 mg Q8W

N=23

n (%)

DAWNZERA

80 mg Q4W

N=45

n (%)

Placebo

N=22

n (%)

Sex

 

 

 

Female

12 (52)

28 (62)

8 (36)

Male

11 (48)

17 (38)

14 (64)

Age group, years

 

 

 

12 to 17

3 (13)

4 (9)

0

18 to 64

19 (83)

40 (89)

22 (100)

≥65

1 (4)

1 (2)

0

Race

 

 

 

American Indian or Alaska Native

1 (4)

0

2 (9)

Asian

0

1 (2)

0

Black or African American

0

1 (2)

1 (5)

Multiple

0

0

1 (5)

White

22 (96)

42 (93)

18 (82)

Other

0

1 (2)

0

Ethnicity

 

 

 

Hispanic or Latino

3 (13)

2 (4)

1 (5)

Not Hispanic or Latino

20 (87)

43 (96)

21 (95)

Geographic region

 

 

 

United States

4 (17)

7 (16)

7 (32)

Rest of the world

19 (83)

38 (84)

15 (68)

Source: Adapted from FDA Review 
Abbreviations: Q4W, every four weeks; Q8W, every eight weeks

What are the benefits of this drug?

In patients 12 years of age and older with HAE, DAWNZERA helped reduce the number of HAE attacks per month over a 24-week period.

What are the benefits of this drug (results of trials used to assess efficacy)? 

The trial demonstrated that treatment with DAWNZERA was superior to placebo in patients 12 years of age and older with HAE. This was measured by the primary endpoint of the time-normalized number of investigator-confirmed HAE attacks per month during a 24-week treatment period. DAWNZERA showed a reduction in the time-normalized number of investigator-confirmed HAE attacks per month compared to placebo.

Table 2. Time-Normalized Number of Investigator-confirmed HAE Attack Rate Per Four Weeks From Week 0 to Week 24, Efficacy Population

Parameter

DAWNZERA

80 mg Q8W
N=23

DAWNZERA

80 mg Q4W
N=45

Placebo
N=22

Least square mean rate (95% CI)

1.02 (0.65, 1.59)

0.44 (0.27, 0.73)

2.26 (1.66, 3.09)

Model adjusted mean rate ratio (95% CI)

0.45 (0.26, 0.78)

0.19 (0.11, 0.35)

NA

Difference versus placebo, % (95% CI)

-55 (-74, -22)

-81 (-89, -65)

NA

Source: Adapted from FDA Review 
Abbreviations: CI, confidence interval; HAE, hereditary angioedema; NA, not applicable; Q4W, every four weeks; Q8W, every eight weeks.

Were there any differences in how well the drug worked in clinical trials among sex, race, and age?

  • Sex: DAWNZERA worked similarly in males and females.
  • Race: The number of patients of races other than White was small; therefore, differences in how DAWNZERA worked among races could not be determined.
  • Age: DAWNZERA worked similarly in adults 18 to 39 years and 40 to 64 years of age. The number of patients younger than 18 years of age or 65 years of age and older was small; therefore, differences in how the drug worked in other age groups could not be determined.
  • Ethnicity: The study did not include a sufficient number of Hispanic or Latino patients; therefore, differences in how DAWNZERA worked among ethnicities could not be determined.

Were there any differences in how well the drug worked in clinical trials among sex, race, and age groups?

Subgroup analyses of the primary endpoint based on sex, race, age, and ethnicity were performed. In general, there were no significant differences in the efficacy of DAWNZERA based on the demographic subgroups, but some subgroups were small.

Table 3. Efficacy Results by Subgroup, Rate Ratio of HAE Attacks through Week 25 Between DAWNZERA and Placebo, Efficacy Population

Subgroup 

n[Q8W], n[Q4W], n[P] 

DAWNZERA Q8W vs. Placebo

Rate Ratio (95% CI) 

DAWNZERA Q4W vs. Placebo

Rate Ratio (95% CI) 

Age group, years 

 

 

 

12 to 17 

3, 4, 0 

X 

X 

18 to 39 

12, 19, 15 

0.33 (0.15, 0.72) 

0.14 (0.06, 0.32) 

40 to 64 

7, 21, 7 

0.54 (0.24, 1.20) 

0.25 (0.12, 0.51) 

≥65 

1, 1, 0 

X 

X 

Sex 

 

 

 

Female 

12, 28, 8 

0.73 (0.32, 1.65) 

0.21 (0.09, 0.52) 

Male 

11, 17, 14 

0.29 (0.12, 0.69) 

0.20 (0.09, 0.45) 

Race 

 

 

 

American Indian or Alaska Native 

1, 0, 2 

0.30 (0.02, 4.78) 

X 

Black or African American 

0, 1, 1 

X 

0.13 (0.00, 4.01) 

White 

22, 42, 18 

0.50 (0.27, 0.91) 

0.22 (0.12, 0.42) 

Ethnicity 

 

 

 

Hispanic or Latino 

3, 2, 1 

X 

X 

Not Hispanic or Latino 

20, 43, 21 

0.51 (0.29, 0.90) 

0.20 (0.11, 0.37) 

Source: Adapted from FDA Review 
Abbreviations: CI, confidence interval; n, number of subjects in subset; HAE, hereditary angioedema; P, placebo; Q8W, DAWNZERA 80 mg every eight weeks; Q4W, DAWNZERA 80 mg every four weeks; X, value cannot be calculated due to zero patients in one or more arms

What are the possible side effects?

DAWNZERA may cause serious side effect, including hypersensitivity reactions (anaphylaxis).

What are the possible side effects (results of trials used to assess safety)?

DAWNZERA may cause serious side effect, including hypersensitivity reactions (anaphylaxis).

Table 4. Safety Results, Safety Population

Preferred Term

DAWNZERA

80 mg Q8W
N=23
n (%)

DAWNZERA

80 mg Q4W
N=45
n (%)

Placebo
N=22
n (%)

Injection site reaction 

1 (4)

11 (24)

1 (5)

Upper respiratory tract infection

2 (9)

4 (9)

1 (5)

Urinary tract infection

2 (9)

4 (9)

0

Abdominal discomfort

0

3 (7)

0

Source: Adapted from FDA Review 
Abbreviations: Q4W, every four weeks; Q8W, every eight weeks

Were there any differences in side effects among sex, race and age?

  • Sex: The occurrence of side effects was similar in males and females.
  • Race: The number of patients of races other than White was small; therefore, differences in the occurrence of side effects among races could not be determined.
  • Age: The occurrence of side effects was similar in adults 18 to 39 years and 40 to 64 years of age. The number of patients younger than 18 years of age or 65 years of age and older was small; therefore, the rate of side effects in other age groups could not be determined.
  • Ethnicity: The study did not include a sufficient number of Hispanic or Latino patients; therefore, differences in the occurrence of side effects among ethnicities could not be determined.

title="MORE INFO" open="no"

Were there any differences in side effects of the clinical trials among sex, race, and age groups?

Table 5. Overview of Adverse Events by Demographic Subgroup, Safety Population

Characteristic

DAWNZERA 80 mg Q8W
N=23
n/Ns (%)

DAWNZERA 80 mg Q4W
N=45
n/Ns (%)

Placebo
N=22
n/Ns (%)

Sex

 

 

 

Female

8/12 (67)

20/28 (71)

6/8 (75)

Male

6/11 (55)

13/17 (77)

12/14 (86)

Age group, years

 

 

 

12 to 17

1/3 (33)

2/4 (50)

0/0 (NA)

18 to 39

8/12 (67)

14/19 (74)

13/15 (87)

40 to 64

5/7 (71)

16/21 (76)

5/7 (71)

≥65

0/1 (0)

1/1 (100)

0/0 (NA)

Race

 

 

 

American Indian or Alaska Native

1/1 (100)

0/0 (NA)

2/2 (100)

Asian

0/0 (NA)

1/1 (100)

0/0 (NA)

Black or African American

0/0 (NA)

1/1 (100)

1/1 (100)

Multiple

0/0 (NA)

0/0 (NA)

1/1 (100)

Other

0/0 (NA)

1/1 (100)

0/0 (NA)

White

13/22 (59)

30/42 (71)

14/18 (78)

Ethnicity

 

 

 

Hispanic or Latino

3/3 (100)

1/2 (50)

1/1 (100)

Not Hispanic or Latino

11/20 (55)

32/43 (74)

17/21 (81)

Is in United States

 

 

 

United States

2/4 (50)

5/7 (71)

6/7 (86)

Non-United States

12/19 (63)

28/38 (74)

12/15 (80)

Source: Adapted from FDA Review 
Abbreviations: N, number of patients in treatment arm; n, number of patients with adverse event; NA, not applicable; Ns, total number of patients for each specific subgroup and were assigned to that specific arm; Q4W, every four weeks; Q8W, every eight weeks

GLOSSARY

CLINICAL TRIAL: Voluntary research studies conducted in people and designed to answer specific questions about the safety or effectiveness of drugs, vaccines, other therapies, or new ways of using existing treatments.
COMPARATOR: A previously available treatment or placebo used in clinical trials that is compared to the actual drug being tested.
EFFICACY: How well the drug achieves the desired response when it is taken as described in a controlled clinical setting, such as during a clinical trial.
PLACEBO: An inactive substance or “sugar pill” that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.
SUBGROUP: A subset of the population studied in a clinical trial. Demographic subsets include sex, race, and age groups.

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