STAR-0215 reduces HAE attacks over 90% in early trial, data show

Astria now planning 2025 launch of Phase 3 trial of injection therapy

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Two hands, a stethoscope, and some medications surround a clinical trial graph showing positively trending results.

Treatment with the experimental under-the-skin injection therapy STAR-0215 reduced the rates of monthly swelling attacks by more than 90% in people with hereditary angioedema (HAE) in a small early clinical trial.

That’s according to new data announced by developer Astria Therapeutics, which further showed that HAE attacks requiring on-demand rescue treatment also dropped by more than 90% in the first four patients participating in the Phase 1b/2 ALPHA-STAR trial. Another 12 patients were treated in two subsequent groups with similar results, the data show.

“Thanks to the enthusiasm for STAR-0215, the ALPHA-STAR trial enrolled ahead of schedule, enabling us to report these data earlier than originally scheduled,” Jill C. Milne, PhD, CEO of Astria, said in a company press release.

Marcus Maurer, MD, executive director of the Institute of Allergology at Charite – Universitatsmedizin Berlin, in Germany, said the results suggest that “STAR-0215 has the potential to normalize the lives of people living with HAE.”

Based on these positive results, Astria now is planning to launch a Phase 3 trial to further test STAR-0215. If those results are consistently positive, the company plans to use them as a basis to apply for regulatory approvals of STAR-0215. Pending feedback from regulatory authorities, Astria expects to start the Phase 3 trial in early 2025, with top-line results anticipated to become available by the end of 2026.

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Preventive therapy found to reduce number, not severity of HAE attacks

STAR-0215 works like approved therapy Takhzyro but isn’t needed as often

An antibody-based therapy, STAR-0215 is designed to block the activity of an enzyme called kallikrein. This enzyme is responsible for producing a signaling molecule called bradykinin. In HAE, genetic mutations lead to the excessive production of bradykinin, which triggers swelling attacks. By blocking kallikrein, the therapy is expected to reduce bradykinin levels and ultimately, prevent swelling.

This mechanism of action is similar to that of Takeda’s approved HAE therapy Takhzyro (lanadelumab), which also is given by a subcutaneous or under-the-skin injection, but every other week or once monthly.

STAR-0215 is being developed with the aim of providing patients with a therapy that has a similar ability to control swelling — but one that doesn’t need to be administered as often, thus easing the burden of treatment for patients.

Astria’s goal is to get the therapy approved as quickly as possible. To that end, the company plans, in the upcoming Phase 3 trial, to test a dosing regimen for STAR-0215 in which the therapy will be given every three months.

Assuming all goes well, the company then plans to immediately launch another trial to test a further dosing regimen in which STAR-0215 would be given every six months.

“These [initial] results give us conviction that we will be able to deliver STAR-0215 once every three and six months, and we look forward to progressing this program into Phase 3 as quickly as possible,” said Christopher Morabito, MD, chief medical officer at Astria.

Morabito said STAR-0215 has the potential to be “a transformative therapy.”

Milne echoed those words, saying, “We believe STAR-0215 has the potential to be the first-choice HAE treatment and I am thankful for the HAE community and the Astria team for helping us to achieve today’s important milestone.”

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Rates of HAE attacks requiring on-demand treatment also dropped over 90%

The ALPHA-STAR clinical trial (NCT05695248) is testing STAR-0215 in adults with HAE types 1 or 2. The study has enrolled a total of 16 participants to date, who were divided into three groups or cohorts. After an eight-week run-in period to assess pre-treatment HAE attack rates, all participants were treated with STAR-0215 — but each cohort received a different dosing schedule.

In the first cohort, four patients were given a single injection of STAR-0215 at a dose of 450 mg. These patients all were followed for at least six months.

Among them, monthly swelling attack rates decreased by 92% on average, with the rate of HAE attacks judged to be moderate or severe reduced by 96%, the results showed. Rates of attacks requiring on-demand rescue treatment fell by 91%, and two of the four patients were attack-free in the first three months after treatment.

The six patients in second cohort were given one injection of 600 mg of STAR-0215, then a second one, containing 300 mg of the therapy, three months later. All six were completely attack-free in the month after the first injection.

Three participants in that second cohort have since been followed for at least six months. In that time, the average rate of monthly swelling attacks decreased by 96%, and two of the three patients were completely attack-free. Rates of moderate to severe attacks and attacks requiring on-demand treatment likewise dropped by more than 90%.

The third cohort included six patients who were given one injection of 600 mg of STAR-0215, followed by a second one of the same dose one month later. Four of these patients have been followed for at least three months; two were attack-free in that time, and average attack rates fell by 90%.

STAR-0215 has the potential to help patients manage their disease with a mechanism and modality that they trust, but with a substantially improved dosing regimen and the ability to administer without pain.

STAR-0215 has so far been generally well tolerated in the study. There were two treatment-related side effects reported, both judged to be mild in severity: one case of dizziness and another of a rash at the injection site. Importantly, patients did not report substantial pain associated with the injection itself.

According to Maurer, “the initial results of the ALPHA-STAR trial represent a very exciting step forward in the HAE treatment landscape.”

“STAR-0215 has the potential to help patients manage their disease with a mechanism and modality that they trust, but with a substantially improved dosing regimen and the ability to administer without pain,” Maurer said.

After completing ALPHA-STAR, patients will have the option to enroll in a long-term study called ALPHA-SOLAR (NCT06007677), in all will be treated with STAR-0215. The therapy will be given every three months at a dose of 300 mg, or every six months at a dose of 600 mg. Initial findings from the two dosing regimens in ALPHA-SOLAR are expected by mid-2025.