FDA Flashback: Breast Cancer Decisions and News From March 2026

Catch a glimpse of the breast cancer–related FDA decisions granted in March 2026, including imminent decisions to watch, as well as a biosimilar approval.

What does the regulatory timeline look like for post-neoadjuvant fam-trastuzumab deruxtecan-nxki (T-DXd; Enhertu) for HER2-positive early breast cancer?

On March 9, 2026, the FDA granted priority review to a supplemental biologics license application (sBLA) seeking the approval of T-DXd for the treatment of patients with HER2-positive breast cancer with residual invasive disease after neoadjuvant HER2-directed therapy.¹ This sBLA submission was supported by data from the phase 3 DESTINY-Breast05 trial (NCT04622319), in which patients who received T-DXd (n = 818) achieved a 53% reduction in the risk of disease progression or death compared with patients treated with ado-trastuzumab emtansine (T-DM1; Kadcyla; n = 817; HR, 0.47; 95% CI, 0.34-0.66; P < .0001).² Additionally, the 3-year invasive disease–free survival rates were 92.4% (95% CI, 89.7%-94.4%) vs 83.7% (95% CI, 80.2%-86.7%) in these respective arms.

The FDA has set a Prescription Drug User Fee Act (PDUFA) target action date of July 7, 2026.¹

What denosumab biosimilar gained approval in March for use in patients with breast cancer?

On March 30, 2026, the FDA approved denosumab-adet (Ponlimsi), a biosimilar referencing denosumab (Prolia), for all indications of the reference product.³ This regulatory decision was supported by a collection of evidence, including clinical data and analytical findings, which showed similar efficacy, safety, and immunogenicity profiles between Ponlimsi and reference denosumab. Notably, Ponlimsi is approved for all indications of Prolia, including the increase of bone mass in women at high risk for fracture who are being treated with adjuvant aromatase inhibitor therapy for the management of breast cancer.

Ponlimsi has a safety warning for severe hypocalcemia in patients with advanced kidney disease. Additionally, patients who have advanced chronic kidney disease—including those dependent on dialysis—are at greater risk of developing severe hypocalcemia following denosumab administration. The presence of chronic kidney disease-mineral bone disorder also increases the risk of hypocalcemia in these patients. Before being treated with Ponlimsi, patients with advanced chronic kidney disease should be evaluated for the presence of chronic kidney disease-mineral bone disorder. From there, patients with advanced chronic kidney disease who receive Ponlimsi should do so under the supervision of a health care provide with expertise in the diagnosis and management of chronic kidney disease-mineral bone disorder.

What other anticipated FDA approvals might alter the breast cancer treatment paradigm over the next quarter?

An sBLA seeking the approval of the antibody-drug conjugate datopotamab deruxtecan-dlnk (Datroway) is under FDA priority review for the first-line treatment of adult patients with unresectable or metastatic triple-negative breast cancer who are not eligible for treatment with PD-1– or PD-L1–directed immunotherapy.⁴ The sBLA has a PDUFA target action date in the second quarter of 2026.

Additionally, an sBLA seeking the approval of neoadjuvant T-DXd followed by paclitaxel, trastuzumab (Herceptin), and pertuzumab (Perjeta) is under FDA review for the treatment of adult patients with high-risk, HER2-positive, stage II/III breast cancer.⁵ The sBLA has a PDUFA target action date of May 18, 2026.

Furthermore, a new drug application (NDA) seeking the approval of vepdegestrant is under FDA review for the treatment of patients with estrogen receptor–positive/HER2-negative, ESR1-mutated advanced or metastatic breast cancer who have received prior endocrine-based therapy.⁶ This NDA has a PDUFA target action date of June 5, 2026.

That’s a wrap!

Want more news? Check out our breast cancer page for the latest updates and expert insights across the field. We’ve got HER2-positive breast cancer treatment developments covered, too!

References

1. Enhertu granted priority review in the U.S. as post-neoadjuvant treatment for patients with HER2 positive early breast cancer. News release. Daiichi Sankyo. March 9, 2026. Accessed April 1, 2026. https://www.biospace.com/press-releases/enhertu-granted-priority-review-in-the-u-s-as-post-neoadjuvant-treatment-for-patients-with-her2-positive-early-breast-cancer
2. Geyer CE, Park YH, Shao Z-M, et al. Trastuzumab deruxtecan (T-DXd) vs trastuzumab emtansine (T-DM1) in patients (pts) with high-risk human epidermal growth factor receptor 2–positive (HER2+) primary breast cancer (BC) with residual invasive disease after neoadjuvant therapy (tx): interim analysis of DESTINY-Breast05. Ann Oncol. 2025;36(suppl 2):S1556-S1557. doi:10.1016/j.annonc.2025.09.021
3. Teva gains biosimilar momentum with U.S. FDA approval of Ponlimsi (denosumab-adet) and dual filing acceptance for biosimilar candidate to Xolair (omalizumab). News release. Teva. March 30, 2026. Accessed April 1, 2026. https://ir.tevapharm.com/news-and-events/press-releases/press-release-details/2026/Teva-Gains-Biosimilar-Momentum-with-U-S--FDA-Approval-of-PONLIMSI-denosumab-adet-and-Dual-Filing-Acceptance-for-Biosimilar-Candidate-to-Xolair-omalizumab/default.aspx
4. Datroway (datopotamab deruxtecan-dlnk) granted priority review in the US as 1st-line treatment for patients with metastatic triple-negative breast cancer who are not candidates for immunotherapy. News release. AstraZeneca. February 3, 2026. Accessed April 1, 2026. https://www.astrazeneca-us.com/media/press-releases/2026/DATROWAY-datopotamab-deruxtecan-dlnk-granted-Priority-Review-in-the-US-as-1st-line-treatment-for-patients-with-metastatic-triple-negative-breast-cancer-who-are-not-candidates-for-immunotherapy.html
5. Enhertu followed by THP supplemental biologics license application accepted in the U.S. for patients with high-risk HER2 positive early-stage breast cancer prior to surgery. News release. Daiichi Sankyo. October 1, 2025. Accessed April 1, 2026. https://www.daiichisankyo.com/files/news/pressrelease/pdf/202510/20251001_E.pdf
6. Arvinas announces FDA acceptance of the new drug application for vepdegestrant for the treatment of ESR1m, ER+/HER2- advanced breast cancer. News release. Arvinas. August 8, 2025. Accessed April 1, 2026. https://ir.arvinas.com/news-releases/news-release-details/arvinas-announces-fda-acceptance-new-drug-application