8-K: Atossa Therapeutics Announces Positive Phase 2 Trial Results for (Z)-Endoxifen in Reducing Breast Density

Atossa Therapeutics reports positive topline data from its Phase 2 KARISMA-Endoxifen study, showing significant reduction in mammographic breast density in premenopausal women.

Summary

• Atossa Therapeutics has released positive results from its Phase 2 KARISMA-Endoxifen trial.
• The study investigated (Z)-endoxifen in premenopausal women with mammographic breast density (MBD).
• The trial, conducted at the Karolinska Institute in Sweden, involved 80 women in each of three arms: placebo, 1mg (Z)-endoxifen, and 2mg (Z)-endoxifen.
• The study lasted six months, with MBD reduction used as a measure of therapy response.
• The 1mg and 2mg (Z)-endoxifen arms showed a significant relative density change of -19.3% and -26.5%, respectively, compared to the placebo arm.
• There was no significant difference in density reduction between the 1mg and 2mg arms.
• A previous study showed that a 10% or greater reduction in breast density after one year of tamoxifen was associated with a 62% reduction in breast cancer incidence after 5 years.
• The mean endoxifen plasma concentration was 5.18 ng/mL in the 1 mg arm and 10.87 ng/mL in the 2 mg arm after one month of therapy, remaining stable through six months.
• Discontinuation rates due to side effects were 4, 5, and 12 in the placebo, 1mg, and 2mg arms, respectively.
• Vasomotor symptoms increased slightly in the active arms, with a mean of 1.4 on a 10-point scale.

Sentiment

Score: 8

Explanation: The document presents very positive results from a Phase 2 trial, suggesting a potential breakthrough in breast cancer prevention. The data is strong, and the management commentary is optimistic. However, further studies and regulatory approvals are still needed.

Positives

• The study demonstrated a significant reduction in mammographic breast density with (Z)-endoxifen.
• The drug was generally well tolerated, with low rates of discontinuation due to side effects.
• The results suggest a potential preventative approach to breast cancer.
• The 1mg dose of (Z)-endoxifen showed comparable efficacy to the 2mg dose, potentially reducing side effects.
• The study showed stable plasma concentrations of endoxifen over the six-month period.

Negatives

• There was a higher rate of discontinuation due to side effects in the 2mg arm compared to the 1mg and placebo arms.
• Vasomotor symptoms, such as night sweats and hot flushes, increased slightly in the active arms.

Risks

• Further analysis of the study is required to confirm the results.
• The study results need to be replicated in larger trials.
• The long-term effects of (Z)-endoxifen are not yet known.
• Regulatory approvals are needed before the drug can be marketed.
• The company faces risks associated with macroeconomic conditions and geopolitical instability.

Future Outlook

Atossa expects to report detailed results at the San Antonio Breast Cancer Symposium in December and publish full results in a peer-reviewed journal next year. The company is also continuing to develop a proprietary oral formulation of (Z)-endoxifen and is studying it in multiple Phase 2 trials.

Management Comments

• Dr. Steven Quay, Chief Executive Officer of Atossa Therapeutics, stated that they are thrilled with the topline results and heartened by the idea that this work may someday lead to a preventative approach to breast cancer.
• Dr. Quay also noted that the potential that 1mg of (Z)-endoxifen may significantly reduce breast density as well as, if not better than currently available therapies, potentially without many of the intolerable side effects, is extremely encouraging.

Industry Context

This announcement is significant in the context of breast cancer prevention, as dense breasts are a known risk factor and current treatments have limitations. The positive results for (Z)-endoxifen could position Atossa as a leader in this area, potentially offering a new preventative option for millions of women.

Comparison to Industry Standards

• The study references a 2011 study where women with a breast density decrease of 10% or greater after taking tamoxifen for one year had a 62% reduction in breast cancer incidence after 5 years.
• The results of the Atossa study show a -19.3% and -26.5% reduction in breast density, which is a significant improvement over the 10% benchmark from the tamoxifen study.
• Tamoxifen is a standard treatment for breast cancer prevention, but it has side effects that can be intolerable for some women.
• The Atossa study suggests that (Z)-endoxifen may be as effective or more effective than tamoxifen, with fewer side effects.
• Other companies such as AstraZeneca and Novartis have developed SERMs for breast cancer treatment, but Atossa's (Z)-endoxifen is specifically being studied for breast density reduction and prevention.

Stakeholder Impact

• Shareholders may see a positive impact due to the promising clinical trial results.
• Patients with dense breasts may benefit from a new preventative treatment option.
• Employees of Atossa may experience increased job security and growth opportunities.
• The medical community may gain a new tool in the fight against breast cancer.

Next Steps

• Atossa and the Karolinska Institute expect to report detailed results from the KARISMA-Endoxifen trial at the San Antonio Breast Cancer Symposium in December.
• The full results of the study are expected to be published in a peer-reviewed journal next year.
• Atossa will continue to develop a proprietary oral formulation of (Z)-endoxifen.
• The company will continue to study (Z)-endoxifen in other Phase 2 trials.

Key Dates

Keywords

Z-endoxifen, breast cancer, mammographic breast density, MBD, cancer prevention, clinical trial, SERM, Atossa Therapeutics, KARISMA-Endoxifen, premenopausal women