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Breast cancerAugust 2026
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Breast Cancer — Monthly Compass
Aug 01–31, 2026 • Priority Updates • 3–5 minute read
 
A curated, practice-minded digest of what moved in breast cancer this month — regulatory signals, clinical development, and the most practice-relevant publications.
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breast cancer updates
Key Highlights
Key Highlights
  • Practice-Changing Updates
    • Phase III OPTIMA demonstrated that Prosigna (PAM50)–directed endocrine therapy was noninferior for invasive breast cancer–free survival, supporting chemotherapy omission in ER‑positive/HER2‑negative early breast cancer with low risk‑of‑recurrence scores despite high clinical risk, including up to nine positive nodes and stage IIIa disease.
  • Key Clinical Development Updates
    • Celcuity submitted an sNDA to the FDA to expand REVTORPYK (gedatolisib) to adults with HR+/HER2‑, PIK3CA‑mutant locally advanced or metastatic breast cancer after progression on endocrine therapy, supported by the VIKTORIA‑1 PIK3CA‑mutant cohort showing significant progression‑free survival benefit versus alpelisib.
    • FDA advanced multiple programs: Fast Track was granted to 858 Therapeutics’ oral PARG inhibitor ETX‑19477 for BRCA‑mutated HR+/HER2‑ unresectable or metastatic disease with Phase 2 monotherapy cohorts enrolling, Olema completed enrollment in the pivotal OPERA‑01 palazestrant monotherapy trial and is advancing OPERA‑02 with top‑line OPERA‑01 data expected in Q1 2027, and Lantern received FDA clearance—following a successful Type C meeting—for a Phase 1b/2 LP‑184 monotherapy study in relapsed/refractory TNBC with homologous recombination deficiency.
  • Important Clinical Trial Publications
    • In HER2‑positive unresectable/metastatic breast cancer previously treated with trastuzumab/taxane in China, trastuzumab rezetecan achieved median progression‑free survival of 30.6 vs 8.3 months against pyrotinib/capecitabine (HR=0.22) with 81.7% objective response rate and 3% interstitial lung disease, with cytopenias as predominant toxicities.
    • Neoadjuvant escalation signals included I‑SPY2 graduation of paclitaxel plus cemiplimab‑rwlc and fianlimab for ERBB2‑negative disease with immune‑signature enrichment and notable adrenal insufficiency, while inetetamab + pyrotinib + docetaxel/carboplatin achieved a 60.2% total pathologic complete response in locally advanced HER2‑positive breast cancer.
  • Key Conference Updates
    • August reporting from ASCO Breakthrough 2026 emphasized accelerating ADC competition in HER2‑positive disease, a push–pull between neoadjuvant escalation and de‑escalation in early settings, and growing readiness of ctDNA to guide surveillance.
    • SABCS 2026 opened its late‑breaking abstract window on August 31 with submissions expected September 1–30 for data generated after July 13, with anticipated features including neoadjuvant IO/HER2 regimens, ADC maturity curves, and MRD use cases.
  • Emerging Themes & Macro-Trends
    • OPTIMA may catalyze guideline debates on Prosigna vs current NCCN‑favored Oncotype DX, with downstream effects on payer coverage and testing algorithms.
    • Strategic priorities highlighted include prioritizing HER2 ADC portfolios with ILD mitigation plans, investing in ctDNA/MRD partnerships and infrastructure, and designing biomarker‑enriched neoadjuvant trials that balance pCR gains against immune‑related adverse events.
FDA Approvals/Withdrawals
FDA Approvals/Withdrawals
  • There are no press releases between 2026-08-01 and 2026-08-31 about breast cancer.
Clinical Development Regulatory Updates
Clinical Development Regulatory Updates
  • Celcuity submitted a supplemental New Drug Application (sNDA) to the FDA for REVTORPYK (gedatolisib) to treat adults with HR+/HER2-, PIK3CA‑mutant locally advanced or metastatic breast cancer after progression on endocrine therapy, seeking to expand upon its existing approval in the PIK3CA–wild‑type population. The filing is supported by the VIKTORIA‑1 PIK3CA‑mutant cohort showing significant progression‑free survival benefit versus alpelisib; Celcuity said it looks forward to working with FDA on the application. (globenewswire.com)¹ (read more)
  • 858 Therapeutics announced FDA Fast Track designation for ETX‑19477, an oral PARG inhibitor, for adults with BRCA‑mutated, HR+/HER2‑ unresectable or metastatic breast cancer. The company noted Fast Track enables more frequent FDA interactions and potential eligibility for rolling review, accelerated approval, or priority review; ETX‑19477 is enrolling Phase 2 monotherapy cohorts in BRCA‑mutated HR+/HER2‑ breast cancer within an ongoing Phase 1/2 study. (investor.wedbush.com)² (read more)
  • Olema Oncology’s Q2 update reiterated that palazestrant (OP‑1250) holds FDA Fast Track designation for ER+/HER2‑ metastatic breast cancer previously treated with endocrine therapy plus a CDK4/6 inhibitor. Olema reported completion of enrollment in the pivotal OPERA‑01 monotherapy trial and continued advancement of OPERA‑02 (palazestrant + ribociclib), with top‑line OPERA‑01 data expected in Q1 2027. (globenewswire.com)³ (read more)
  • Prelude Therapeutics stated it expects to initiate a first‑in‑human Phase 1 study of PRT13722, a first‑in‑class oral KAT6A degrader for HR+ breast cancer, in Q4 2026 pending FDA IND clearance. The update followed presentation of supportive preclinical data and emphasized that IND clearance is the gating regulatory step. (preludetx.gcs-web.com)⁴ (read more)
  • OnKure Therapeutics reported it is executing IND‑enabling activities for OKI‑345, a next‑generation PI3Kα pan‑mutant selective inhibitor for breast cancer, with an IND submission to the FDA planned for 1H 2027. The program is designed to spare wild‑type PI3Kα to mitigate class‑limiting toxicities as it progresses toward the planned IND filing. (rss.globenewswire.com)⁵ (read more)
  • Lantern Pharma reported FDA clearance of its Phase 1b/2 trial of LP‑184 monotherapy in relapsed/refractory triple‑negative breast cancer with homologous recombination deficiency and noted a successful FDA Type C meeting that addressed key protocol amendments. The company said the TNBC study is advancing toward initiation following the agency’s clearance. (ir.lanternpharma.com)⁶ (read more)
Conference
Major Conference Updates
Conference Information
  • ASCO Breakthrough 2026, Singapore, June 25–27, 2026 (covered in August press reporting); SABCS 2026, San Antonio, Texas, December 8–11, 2026 (late-breaking window opened August 31). (read more)
  • Sentiment: August outputs signal accelerating ADC competition in HER2+ disease, push–pull between neoadjuvant escalation and de-escalation in early settings, and growing readiness of ctDNA to guide surveillance. (read more)
  • Theme 1: Next‑Wave HER2 ADC Momentum
    • Significance: Trastuzumab rezetecan produced a large PFS gain vs pyrotinib/capecitabine (30.6 vs 8.3 months; HR=0.22), signaling competitive pressure on existing HER2+ metastatic treatment sequences. (read more)
    • Mechanism insights / clinical impact: As a HER2‑directed antibody‑drug conjugate, it delivered higher ORR (81.7%) with low interstitial lung disease incidence (3%); cytopenias predominated—differentiation hinges on efficacy durability and ILD risk management. (read more)
    • Patient populations affected: HER2‑positive unresectable/metastatic breast cancer previously treated with trastuzumab/taxane in China; potential regional first adoption with downstream global implications. (read more)
  • Theme 2: Neoadjuvant Escalation Drives Higher pCR
    • Significance: Dual checkpoint blockade plus chemotherapy improved pathologic complete response across ERBB2‑negative subtypes in I‑SPY2; a parallel HER2‑targeted regimen achieved high pCR in locally advanced disease—together underscoring escalation’s value where relapse risk is highest. (read more)
    • Mechanism insights / clinical impact: Adding PD‑1 (cemiplimab‑rwlc) and LAG‑3 (fianlimab) to paclitaxel‑based therapy met I‑SPY2 graduation criteria with immune‑signature enrichment but notable adrenal insufficiency; inetetamab (enhanced ADCC) + pyrotinib (pan‑HER TKI) + docetaxel/carboplatin delivered total pCR 60.2%. (read more)
    • Patient populations affected: Early‑stage, high‑risk ERBB2‑negative (including TNBC and HR‑positive/ERBB2‑negative) and stage II–III HER2‑positive patients with high tumor burden (primarily China). (read more)
  • Theme 3: Precision De‑escalation and MRD‑Informed Surveillance
    • Significance: OPTIMA supports chemotherapy omission when Prosigna (PAM50) risk‑of‑recurrence is low despite high clinical risk; tissue‑free ctDNA shows strong prognostic power and earlier relapse signal, enabling surveillance without tumor tissue. (read more)
    • Mechanism insights / clinical impact: Test‑directed endocrine therapy was noninferior for invasive breast cancer–free survival; methylation‑based ctDNA detection provided ∼8‑month median lead time and sometimes outperformed dPCR, positioning MRD assays for trial endpoints and clinic workflows. (read more)
    • Patient populations affected: ER‑positive/HER2‑negative early breast cancer with up to nine positive nodes and stage IIIa (de‑escalation); early TNBC post‑adjuvant on MRD surveillance pathways. (read more)
  • Significance
    • Expected clinical or translational readouts: SABCS late‑breaking abstracts (Sept 1–30; data generated after July 13) should feature neoadjuvant IO/HER2 regimens, ADC maturity curves, and MRD use cases. (read more)
    • Regulatory or policy implications: OPTIMA may catalyze guideline debates on assay selection (Prosigna vs current NCCN‑favored Oncotype DX), affecting payer coverage and testing algorithms. (read more)
    • Potential shifts in standard of care: If confirmed and regionally approved, trastuzumab rezetecan could reorder HER2+ metastatic lines in China; I‑SPY2 signals momentum for dual‑checkpoint neoadjuvant strategies pending toxicity management. (read more)
    • Strategic implications: Prioritize ADC portfolios with ILD mitigation plans, invest in ctDNA/MRD partnerships and infrastructure, and design biomarker‑enriched neoadjuvant trials balancing pCR gains against immune‑related AEs. (read more)
Publications Related to Approved Drugs
Phase 3
olaparib
Sustained benefit of adjuvant olaparib in women with germline BRCA1- and BRCA2- -associated high-risk HER2-negative early breast cancer: Updated results from the OlympiA phase III trial. With a median follow-up of 6.1 years, the OlympiA trial demonstrates that one year of adjuvant olaparib continues to provide a statistically significant and clinically meaningful benefit in invasive disease-free survival, distant disease-free survival, and overall survival for patients with gBRCA-mutated, high-risk, HER2-negative early breast cancer. The long-term safety profile is favorable, with no new signals or increased risk of myelodysplastic syndrome or acute myeloid leukemia, solidifying its role as a standard of care in this patient population. ()
Phase 3
pertuzumab, pertuzumab, trastuzumab, and hyaluronidase-zzxf
The benefit of adjuvant pertuzumab and trastuzumab according to estrogen receptor and HER2 expression: a subanalysis of the APHINITY trial. This exploratory subanalysis of the APHINITY trial investigated the benefit of adding pertuzumab to adjuvant trastuzumab and chemotherapy across different biomarker subgroups in HER2-positive early breast cancer. While all subgroups benefited, the greatest improvement in invasive disease-free survival was observed in patients with tumors that were HER2 FISH-low (ratio 2 to <5) and estrogen receptor-positive, suggesting these biomarkers may help identify patients likely to derive the most benefit from dual HER2 blockade. ()
Phase 3
alpelisib
Genomic determinants of response to alpelisib plus fulvestrant in the SOLAR-1 trial. In a retrospective analysis of the SOLAR-1 trial, alpelisib plus fulvestrant demonstrated clinical benefit across a range of co-mutations in patients with PIK3CA-altered, HR-positive, HER2-negative advanced breast cancer. Notably, patients with FGFR1 or FGFR2 alterations or those in the lowest tumor mutational burden quartile derived enhanced progression-free survival benefit, providing new insights into genomic markers that may predict a greater response to PI3Kα-inhibition. ()
Phase 3
letrozole and ribociclib, ribociclib
Quantitative Pharmacology Justifying Ribociclib Dose in Early Breast Cancer. This quantitative pharmacology analysis across several pivotal trials provides the rationale for the 400 mg starting dose of ribociclib in early breast cancer (EBC), as opposed to the 600 mg dose used in the advanced setting. The study identified different pharmacokinetic profiles between patient populations and confirmed that the 400 mg dose in EBC patients results in lower rates of neutropenia and QTcF prolongation, thereby optimizing the benefit-risk profile for the adjuvant setting. ()
Phase 3
pertuzumab, trastuzumab, and hyaluronidase-zzxf
Final analysis of the FeDeriCa phase III study: long-term efficacy, safety and pharmacokinetics of the fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection, plus chemotherapy, in HER2-positive early breast cancer. The final analysis from the FeDeriCa study, with a median follow-up of over four years, confirms that the subcutaneous fixed-dose combination of pertuzumab and trastuzumab has comparable long-term efficacy and safety to the intravenous formulations for HER2-positive early breast cancer. These results establish the subcutaneous injection as a faster, less invasive, and patient-preferred administration option without compromising clinical outcomes. ()
Phase 2
tucatinib
Clinical management of adverse events in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer treated with tucatinib, trastuzumab, and capecitabine. Based on experience from the HER2CLIMB trial and clinical practice, this article provides expert guidance and visual algorithms for managing the most common adverse events associated with the tucatinib, trastuzumab, and capecitabine regimen. The review offers practical strategies for proactively managing diarrhea, liver enzyme elevations, and palmar-plantar erythrodysesthesia to optimize treatment tolerability and duration for patients with HER2-positive metastatic breast cancer. ()
Phase 3
vepdegestrant
Population Pharmacokinetics and Exposure-Response Analyses of Vepdegestrant, a First-in-Class PROteolysis-TArgeting Chimera Estrogen Receptor Degrader. An integrated analysis of the first-in-human and VERITAC-2 studies characterized the pharmacokinetics of vepdegestrant, a novel oral PROTAC estrogen receptor degrader, in patients with ER-positive, HER2-negative advanced breast cancer. The findings showed no significant relationship between drug exposure and key efficacy or safety endpoints, supporting the 200 mg once-daily dose and demonstrating a predictable profile for this emerging therapeutic class. ()
New Publications Related to Drugs in Clinical Trial Development
Phase 1
Outcomes After Intratumoral Delivery of Immunotherapy in Breast Cancer. A retrospective review of 111 patients demonstrates that intratumoral immunotherapy injections are a safe and feasible treatment option for breast cancer, potentially minimizing systemic adverse events while maintaining efficacy. Systemic side effects like chills and fever were more common than local reactions, but the approach is viable. ()
Phase 2
Biomarker-guided responses in patient-derived organoids predict effective therapies in breast cancer. This study demonstrates that patient-derived breast cancer organoids can effectively model therapy resistance and predict responses to various treatments, including identifying novel combinations to overcome resistance. These organoid-based functional models serve as a crucial link between clinical biomarkers and the development of precision treatment strategies. ()
Phase 2
Surgical Management of Young Women with High-Risk Breast Cancer Receiving Neoadjuvant Systemic Therapy on the I-SPY2 Trial. An analysis of the I-SPY2 trial data revealed that while younger women (≤ 45 years) with high-risk breast cancer are more likely to undergo mastectomy after neoadjuvant therapy, the greater extent of surgery was not associated with improved overall survival or reduced locoregional recurrence. This suggests that young age alone is not a sufficient reason for recommending mastectomy post-neoadjuvant treatment. ()
Phase 2
Outcomes After Intratumoral Delivery of Immunotherapy in Breast Cancer. A retrospective review of 111 patients demonstrates that intratumoral immunotherapy injections are a safe and feasible treatment option for breast cancer, potentially minimizing systemic adverse events while maintaining efficacy. Systemic side effects like chills and fever were more common than local reactions, but the approach is viable. ()
Phase 2
Outcomes After Intratumoral Delivery of Immunotherapy in Breast Cancer. A retrospective review of 111 patients demonstrates that intratumoral immunotherapy injections are a safe and feasible treatment option for breast cancer, potentially minimizing systemic adverse events while maintaining efficacy. Systemic side effects like chills and fever were more common than local reactions, but the approach is viable. ()
PHASE1, PHASE2
Immuno-PET/CT Imaging of Trop2 Expression with [18F]AlF-RESCA-RT4 Enhances Diagnosis of Breast Cancers and the Metastases. A novel Trop2-targeted tracer, [18F]AlF-RESCA-RT4, demonstrated high sensitivity and specificity for diagnosing Trop2-positive breast cancer across all molecular subtypes. The tracer offered superior diagnostic performance for detecting nodal and bone metastases compared to traditional 18F-FDG PET/CT. ()
Phase 2
Efficacy and safety of trastuzumab deruxtecan in patients with HER2-expressing biliary tract or pancreatic tumors: a subgroup analysis of DESTINY-PanTumor02. In a subgroup analysis of the DESTINY-PanTumor02 trial, trastuzumab deruxtecan (T-DXd) demonstrated a clinically meaningful objective response rate of 22% in patients with HER2-expressing biliary tract cancer, particularly in those with IHC 3+ tumors. However, its efficacy in pancreatic cancer was limited, though interpretation was constrained by the small sample size. ()
PHASE1, PHASE2
Quantitative characterization of platelet count and alanine aminotransferase dynamics to inform personalized dosing in the first-in-human LP-184 trial. This study utilized in-depth data analytics from the first-in-human trial of LP-184 to characterize the dynamics of platelet and ALT levels, identifying baseline platelet counts and dose as critical contributors to toxicity. This quantitative approach facilitates the development of a personalized dosing strategy to enhance patient safety in future studies. ()
Phase 2
First-line PD-1/VEGF bispecific antibody plus chemotherapy in triple-negative breast cancer: a phase 2 trial. The combination of ivonescimab, a PD-1/VEGF bispecific antibody, with chemotherapy as a first-line treatment for advanced triple-negative breast cancer demonstrated an encouraging objective response rate of 80.0% with a manageable safety profile. These results support further investigation of this combination in this patient population. ()
Phase 3
Datopotamab deruxtecan versus chemotherapy in previously treated inoperable/metastatic hormone receptor-positive HER2-negative breast cancer: safety and patient-reported outcomes from the phase III TROPION-Breast01 study. In the TROPION-Breast01 trial, datopotamab deruxtecan (Dato-DXd) demonstrated a manageable safety profile, with stomatitis and ocular surface events being the most common AEs of special interest, and delayed the time to deterioration in quality of life compared to chemotherapy. These findings complement the efficacy data, supporting Dato-DXd as a new treatment option for previously treated HR+/HER2- breast cancer. ()
Phase 2
Enfortumab Vedotin plus Pembrolizumab as First-line Treatment in Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma: Results from EV-202 Cohort 9. The combination of enfortumab vedotin and pembrolizumab showed promising clinical activity as a first-line treatment for patients with PD-L1 positive recurrent or metastatic head and neck squamous cell carcinoma, achieving a confirmed objective response rate of 39%. The safety profile was manageable, reinforcing the potential of this combination therapy. ()
Phase 2
Precision neoadjuvant treatment with AI-assisted subtyping in HR+/HER2-breast cancer: A randomized, phase 2 trial FASCINATE-N. This phase 2 trial demonstrated that using an AI-assisted digital pathology classification to guide neoadjuvant precision treatment in HR+/HER2- breast cancer significantly improved the pathological complete response rate (11.1% vs. 4.0%). The benefit was primarily seen in the "targeted-based" patient group, highlighting the potential of this subtyping method to personalize therapy. ()
Phase 2
Rationale and trial design of RIBOLARIS: A phase II trial of neoadjuvant and adjuvant ribociclib plus endocrine therapy for clinically high-risk HR+/HER2-negative breast cancer. The RIBOLARIS trial is a phase II study designed to determine if chemotherapy can be safely omitted in patients with high-risk HR+/HER2- early breast cancer who achieve a low genomic risk status after receiving neoadjuvant ribociclib plus letrozole. This study aims to use molecular response to de-escalate therapy and avoid unnecessary chemotherapy exposure. ()
Phase 3
Trastuzumab rezetecan versus pyrotinib plus capecitabine for patients with HER2-positive metastatic breast cancer (HORIZON-Breast01): interim analysis of a multicentre, open-label, randomised, controlled, phase 3 trial. An interim analysis of the HORIZON-Breast01 phase 3 trial showed that trastuzumab rezetecan significantly improved progression-free survival compared to pyrotinib plus capecitabine (30.6 months vs. 8.3 months) in patients with previously treated HER2-positive metastatic breast cancer. This positions trastuzumab rezetecan as a potential new standard of care in this setting. ()
Phase 2
CDK4/6 inhibitors as conditional immune-priming agents in breast cancer: therapeutic windows, sequencing strategies, and rational combinations with immunotherapy, radiotherapy, and antibody-drug conjugates. This review article synthesizes evidence on the immunomodulatory effects of CDK4/6 inhibitors, proposing a "therapeutic window" strategy where a defined exposure is used to achieve a measurable immune change before combining or sequencing with other treatments like immunotherapy or ADCs. This approach aims to optimize efficacy while managing toxicity. ()
Phase 2
Phase 2 test of QBS72S for breast cancer leptomeningeal disease. In a phase 2a trial, the novel blood-brain barrier-penetrating molecule QBS72S was found to be adequately tolerated and demonstrated preliminary efficacy in patients with breast cancer leptomeningeal disease. Two of the ten patients treated exhibited long-term radiographic stability or improvement, supporting further investigation of this targeted therapy for a high unmet need population. ()
PHASE1, PHASE2
Durvalumab plus Paclitaxel, with or without Capivasertib or Oleclumab, in Patients with Locally Advanced/Metastatic Triple-Negative Breast Cancer. The BEGONIA platform study showed that the combination of durvalumab plus paclitaxel has clinical activity in first-line metastatic triple-negative breast cancer, with a confirmed objective response rate of 56.5%. The addition of either the AKT inhibitor capivasertib or the anti-CD73 antibody oleclumab did not provide substantial additional benefit. ()
PHASE1, PHASE2
Datopotamab deruxtecan (Dato-DXd) in combination with durvalumab as first-line treatment for unresectable locally advanced or metastatic triple-negative breast cancer: results from arms 7 and 8 of the phase Ib/II BEGONIA study. The combination of datopotamab deruxtecan (Dato-DXd) and durvalumab demonstrated substantial and durable antitumor activity as a first-line treatment for metastatic triple-negative breast cancer, achieving a confirmed objective response rate of 79.0%. The safety profile of the combination was manageable and consistent with prior studies of the individual agents. ()
N/A
The Vanguard Study: Assessing feasibility of conducting randomized trials of novel multi-cancer detection tests. The Vanguard Study is the first U.S. randomized trial of Multi-Cancer Detection (MCD) tests, designed to evaluate the feasibility of critical protocol components for a future large-scale trial. This study will enroll 18,000-24,000 participants to inform the design and implementation of a definitive trial to assess the public health benefits of MCDs. ()
Phase 3
SERENA-6 visual patient-reported outcomes and safety: camizestrant for emerging ESR1m advanced breast cancer during first-line endocrine-based therapy. This analysis from the SERENA-6 study characterized the visual side effects of camizestrant, finding that they were mostly mild, short-lived, and reversible after treatment. These events did not lead to treatment discontinuation or impact ocular structure or function, supporting the visual safety profile of camizestrant. ()
Phase 3
Switching to camizestrant at ESR1 mutation emergence before disease progression during first-line treatment of hormone receptor-positive advanced breast cancer (SERENA-6): extended analysis of a double-blind, placebo-controlled, randomised, phase 3 trial. The SERENA-6 trial demonstrated that a ctDNA-guided strategy of switching from an aromatase inhibitor to camizestrant upon detection of an ESR1 mutation significantly improved progression-free survival (16.8 vs. 9.2 months) and second progression-free survival. These results support changing endocrine therapy to camizestrant to extend the benefit of first-line treatment in HR-positive advanced breast cancer. ()
Phase 3
TroFuse-011 study design: sacituzumab tirumotecan with or without pembrolizumab for advanced triple-negative breast cancer with PD-L1 CPS <10. The TroFuse-011 study is a clinical trial designed to evaluate sacituzumab tirumotecan, a novel TROP2-directed antibody-drug conjugate, either alone or in combination with pembrolizumab, versus standard chemotherapy. The trial focuses on patients with previously untreated, advanced triple-negative breast cancer who have low PD-L1 expression (CPS <10), a population with poor outcomes. ()
Phase 1
Neoadjuvant Paclitaxel, Trastuzumab, and Pertuzumab for Stage II to III, ERBB2-Positive Breast Cancer: A Secondary Analysis of the DAPHNe Trial. A 5-year follow-up from the DAPHNe trial confirms that an abbreviated 12-week neoadjuvant regimen of paclitaxel, trastuzumab, and pertuzumab (THP) is associated with excellent long-term outcomes in early-stage HER2-positive breast cancer. Ultrasensitive ctDNA analysis showed high rates of clearance after this de-escalated therapy, supporting further investigation of ctDNA-guided treatment strategies. ()
PHASE1, PHASE2
Quantitative Pharmacology Justifying Ribociclib Dose in Early Breast Cancer. This integrative analysis of pharmacokinetic and safety data justified the approval of a lower 400 mg starting dose of ribociclib for early breast cancer, compared to the 600 mg dose used in advanced disease. The study identified significant differences in drug clearance and QTcF interval response between the two patient populations, highlighting the value of quantitative pharmacology in dose optimization. ()
Phase 2
Dalpiciclib plus endocrine therapy in women with HR+/HER2- advanced breast cancer and visceral crisis: a multicenter, nonrandomized, phase 2 DARVIN trial. The phase 2 DARVIN trial showed that dalpiciclib combined with endocrine therapy is a promising option for HR+/HER2- advanced breast cancer patients experiencing visceral crisis, a challenging clinical scenario. The regimen achieved a 92.5% 6-month survival rate and a median progression-free survival of 11.2 months, meeting its primary endpoint. ()
Phase 2
Pathologic Complete Response (pCR) Rate and Predictors of Response to Taxane, Trastuzumab, and Pertuzumab in HER2-Positive Breast Cancer: Secondary Analyses of EA1181/CompassHER2 pCR. Secondary analysis of the CompassHER2 pCR trial found that neoadjuvant taxane, trastuzumab, and pertuzumab (THP) resulted in an overall pathologic complete response rate of 43.8% in stage II/IIIa HER2-positive breast cancer. Higher pCR rates were strongly associated with ER-negative status (63.7%) and a high HER2DX pCR score, providing valuable data for risk stratification. ()
PHASE1, PHASE2
A Phase I/II Study of Ibrutinib Plus Trastuzumab in HER2-Positive Metastatic Breast Cancer. In a phase I/II study, the combination of ibrutinib and trastuzumab was well-tolerated but demonstrated limited anti-tumor activity in heavily pretreated patients with HER2-positive metastatic breast cancer, with a clinical benefit rate of 19.2%. Immunomodulatory effects were observed, including a decrease in T helper 17 cells and myeloid-derived suppressor cells. ()
N/A
Rationale and design of a CArdiac Rehabilitation program on the Prevention of CardioTOXicity in Breast Cancer patients undergoing treatment with anthracyclines and/or trastuzumab (CARPTOX-BC) trial: a randomized, active control group, open-label trial. The CARPTOX-BC trial is a randomized study designed to assess whether a structured exercise program can effectively prevent cancer therapy-related cardiac dysfunction in breast cancer patients receiving cardiotoxic treatments like anthracyclines or trastuzumab. The study aims to establish a non-pharmacological strategy to mitigate cardiotoxicity and improve quality of life. ()
Phase 3
Dose-dense adjuvant chemotherapy in HER2-low breast cancer: An exploratory analysis of the GIM2 trial. An exploratory analysis of the GIM2 trial with nearly 15 years of follow-up showed that the survival benefit of dose-dense adjuvant chemotherapy for high-risk, node-positive early breast cancer is maintained regardless of HER2 status. The efficacy was observed in both HER2-zero and HER2-low patient subgroups. ()
Phase 2
Tucatinib in Combination With Trastuzumab Deruxtecan in Patients With Previously Treated HER2+ Unresectable Locally Advanced or Metastatic Breast Cancer: An Open-Label Phase 2 Study. The HER2CLIMB-04 study evaluated the combination of tucatinib and trastuzumab deruxtecan (T-DXd) in previously treated HER2+ metastatic breast cancer. While the addition of tucatinib to T-DXd did not show a clear benefit over historical T-DXd monotherapy efficacy, the combination was tolerable with antidiarrheal prophylaxis and demonstrated clinical activity. ()
Phase 2
Molecular evaluation of residual disease following neoadjuvant chemotherapy in triple negative breast cancer CALGB40603 (Alliance). This study performed comprehensive transcriptomic profiling on residual disease (RD) from the CALGB 40603 trial, identifying that a Basal-like subtype in RD specimens is associated with poor survival and an immune-cold microenvironment. Preclinical models suggest this high-risk group may derive benefit from adjuvant antibody-drug conjugate therapy. ()
PHASE1, PHASE2
Population Pharmacokinetics and Exposure-Response Analyses of Vepdegestrant, a First-in-Class PROteolysis-TArgeting Chimera Estrogen Receptor Degrader. Integrated pharmacokinetic analyses for vepdegestrant, a novel oral SERD, showed no significant relationship between drug exposure and efficacy (progression-free survival) or key safety outcomes. These findings support the selected 200 mg once-daily dose for patients with ER+/HER2- advanced breast cancer. ()
Phase 1
Lipid Nanoparticle-Encapsulated mRNA-2752 Encoding Human OX40L, IL-23, and IL-36γ plus Durvalumab Induces an Immunostimulatory Effect within the Tumor Microenvironment in Patients with Advanced Solid Tumors. The intratumoral injection of mRNA-2752, a novel mRNA-based therapeutic, in combination with durvalumab demonstrated manageable safety and induced a sustained inflammatory response within the tumor microenvironment. This approach showed antitumor activity in heavily pretreated patients, including a 17.9% objective response rate in those with CPI-resistant melanoma. ()
Phase 2
Cognitive workload and its relationship with neurocognitive performance before and after breast cancer chemotherapy. This study found that a real-time, task-specific self-report measure of cognitive workload (NASA-TLX) was robustly associated with worse objective neurocognitive performance, especially in executive function, among breast cancer patients undergoing chemotherapy. This suggests that assessing perceived workload during tasks may be a more sensitive way to characterize cancer-related cognitive impairment than recall-based questionnaires. ()
Phase 3
Primary results from EL1SSAR, a prospective phase IIIb study of first-line atezolizumab plus nab-paclitaxel therapy for patients with PD-L1-positive advanced triple-negative breast cancer. The EL1SSAR study confirmed the safety and efficacy of first-line atezolizumab plus nab-paclitaxel for PD-L1-positive advanced triple-negative breast cancer in a real-world setting that included a broader patient population. The results, including a median overall survival of 27.0 months, were consistent with the pivotal IMpassion130 trial. ()
PHASE1, PHASE2
Outcomes After Intratumoral Delivery of Immunotherapy in Breast Cancer. A retrospective review of 111 patients demonstrates that intratumoral immunotherapy injections are a safe and feasible treatment option for breast cancer, potentially minimizing systemic adverse events while maintaining efficacy. Systemic side effects like chills and fever were more common than local reactions, but the approach is viable. ()
Phase 1
A phase 1, open-label study evaluating the pharmacokinetics, safety, and tolerability of vepdegestrant in Chinese patients with ER+/HER2- advanced breast cancer. This phase 1 study established that the novel oral SERD vepdegestrant has a comparable pharmacokinetic profile and a well-tolerated safety profile in Chinese patients with ER+/HER2- advanced breast cancer. The drug also showed preliminary signs of antitumor activity in this heavily pretreated population. ()
Early Phase 1
Outcomes After Intratumoral Delivery of Immunotherapy in Breast Cancer. A retrospective review of 111 patients demonstrates that intratumoral immunotherapy injections are a safe and feasible treatment option for breast cancer, potentially minimizing systemic adverse events while maintaining efficacy. Systemic side effects like chills and fever were more common than local reactions, but the approach is viable. ()
Phase 2
Body mass index in postmenopausal women with estrogen receptor-positive, HER2-negative early breast cancer: An exploratory analysis of the LORELEI trial. An analysis of the LORELEI trial revealed that obesity was associated with a lower objective response rate to letrozole alone in patients with ER+/HER2- early breast cancer. However, this negative association was not observed in patients who received the PI3K inhibitor taselisib in addition to letrozole, suggesting PI3K inhibition may overcome obesity-related resistance. ()
Phase 3
Biomarker-calibrated dietary macronutrient densities and their comparative associations with chronic disease risk in a cohort of postmenopausal females. Using biomarker-calibrated dietary data from the Women's Health Initiative, this study found that higher saturated fatty acid intake was associated with an increased risk of coronary artery disease, while higher polyunsaturated fatty acid intake was linked to an increased risk of breast cancer. Both were associated with a higher risk of type 2 diabetes. ()
Phase 2
Quantitative Pharmacology Justifying Ribociclib Dose in Early Breast Cancer. This integrative analysis of pharmacokinetic and safety data justified the approval of a lower 400 mg starting dose of ribociclib for early breast cancer, compared to the 600 mg dose used in advanced disease. The study identified significant differences in drug clearance and QTcF interval response between the two patient populations, highlighting the value of quantitative pharmacology in dose optimization. ()
Clinical Trials
Clinical Trials Summary
Number of Clinical Trials in breast cancer updated from 2026-08-01 to 2026-08-31:
Phase 1Phase 1/2Phase 2Phase 2/3Phase 3Phase 4Total
Enrolling by Invitation1-11--3
Not Yet Recruiting31019-6240
Recruiting403150325-149
Available-------
Approved for Marketing-------
Active, Not Recruiting23826-21-78
Completed--2---2
Total6749984522272
Phase 1 Clinical Trials within 3 Months of Primary Completion Date:
DRUGNCTIDStatusClinical Trial NameCompletion Date
HRS-6209 Capsule (new formulation), HRS-6209 Capsule (old formulation) NCT07610148 ACTIVE_NOT_RECRUITING A Single-Center, Single-Dose, Randomized, Open-Label, Three-Period, Three-Sequence, Crossover Study to Evaluate the Oral Relative Bioavailability of Old and New Formulations of HRS-6209 Capsules and the Effect of Food in Healthy Chinese Participants 2026-09
Endoxifen Hydrochloride NCT01327781 ACTIVE_NOT_RECRUITING Phase I Study of Z-Endoxifen as a Hormonal Therapy for Breast Cancer 2026-10-30
Phase 2 Clinical Trials within 3 Months of Primary Completion Date:
DRUGNCTIDStatusClinical Trial NameCompletion Date
Tamoxifen, Exemestane 25 mg, Letrozole 2.5mg, Anastrozole 1mg NCT05150652 COMPLETED Phase 2 Study of Neoadjuvant Endocrine Therapy in ER-positive, HER2-negative Early Stage Breast Cancer 2026-06-10
SKB264, KL-A167 NCT05445908 COMPLETED A Phase 2 Clinical Study of SKB264 With/Without KL-A167 in Patients With Unresectable Locally Advanced, Recurrent or Metastatic HER2-negative Breast Cancer Who Have Not Received Prior Systemic Therapy 2026-07-31
18F-DCFPyL NCT04573231 RECRUITING Evaluation of Prostate Specific Membrane Antigen (PSMA) in HER2-negative, Androgen Receptor (AR)-Positive Metastatic Breast Cancer With 18F-DCFPyL PSMA-based PET/CT 2026-08
Durvalumab NCT05215106 ACTIVE_NOT_RECRUITING Short-term Pre-OPerative Durvalumab (MEDI 4736) in Early Small Triple Negative Breast Cancer Patients (POP-Durva) 2026-09-15
Phase 3 Clinical Trials within 3 Months of Primary Completion Date:
DRUGNCTIDStatusClinical Trial NameCompletion Date
Nuvastatic 300 NCT07669467 RECRUITING A Randomized, Double-Blind, Placebo-Controlled, Multicenter, Phase III Study to Evaluate the Efficacy and Safety of Nuvastatic® 300 mg Capsules in Reducing Chemotherapy-Induced Fatigue in Patients With Metastatic Triple-Negative Breast Cancer Receiving Standard Chemotherapy 2026-10-30
Phase 4 Clinical Trials within 3 Months of Primary Completion Date:
No phase 4 trials completing within the next three months.
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