📬 Breast Cancer Intelligence Digest — Week 2026-W31

Gedatolisib's FDA approval sparks a doublet-versus-triplet debate, camizestrant is approved in the EU, CHMP backs T-DXd plus pertuzumab and sacituzumab govitecan plus pembrolizumab, and ASCO's risk-adapted surveillance guideline draws pushback from patient advocates.

⚡ TL;DR

🐦 Twitter / 🦋 Bluesky

Update: ASCO's risk-adapted surveillance guideline meets patient-advocate pushback on ctDNA and individualized follow-up — The guideline sets clinical follow-up annually for low risk, every 6-12 months for intermediate risk and every 3-6 months for high risk, and advises against routine CT/PET-CT, bone scan, CBC, CEA, CA 15-3, CA 27.29 and ctDNA surveillance outside clinical trials
Update: after gedatolisib's FDA approval, the debate turns to doublet versus triplet and IV burden — VIKTORIA-1 was not designed to compare the two gedatolisib arms, yet the PFS improvement over fulvestrant was similar with or without palbociclib (HR 0.24, HR 0.33, with overlapping 95% CI)
CHMP positive opinion for T-DXd plus pertuzumab in first-line HER2-positive metastatic breast cancer — The EMA's CHMP issued a positive opinion recommending trastuzumab deruxtecan plus pertuzumab for the first-line treatment of HER2-positive metastatic breast cancer
Gedatolisib plus trastuzumab shows activity in PIK3CA-mutant HER2+ metastatic breast cancer — Approximately 30% of HER2+ breast cancers harbor PIK3CA mutations, and gedatolisib plus trastuzumab yielded an ORR of 43% and PFS 6 months in pretreated PIK3CA-mutant HER2+ MBC, with stomatitis the key toxicity
Somatic BRCA alterations are not clinically equivalent to germline BRCA mutations on CDK4/6 inhibitors — In a large real-world study, shorter CDK4/6 inhibitor treatment duration was observed only in germline BRCA carriers, while patients with somatic BRCA alterations alone had outcomes similar to BRCA-wildtype patients

Full details below ↓

📄 What's Being Published

Manuscripts:

Multikinase Inhibition with Tinengotinib in Advanced Solid Tumors: Results from a Multicenter Phase Ib/II Trial. — Piha-Paul Sarina A et al., Clin Cancer Res

Among 197 patients receiving tinengotinib, treatment-related treatment-emergent adverse events occurred in 160 (81.2%) patients, most commonly hypertension. The objective response rate was 30.0% in breast cancer (n=20) and 33.3% in prostate cancer (n=15), while clinical benefit was achieved by 33/159 (20.8%) evaluable patients, including 1 complete response, 20 partial responses, and 12 stable diseases at least 6 months. Observations in breast cancer including ROS1 alterations were exploratory and hypothesis-generating.

Clinical bottom line: Tinengotinib produced a 30.0% response rate in a small pretreated breast cancer cohort with manageable toxicity, and the 10-mg daily dose should carry forward into biomarker-selected breast cancer cohorts.

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Tumor infiltrating lymphocytes as a predictor of adjuvant avelumab efficacy in patients with high-risk triple negative breast cancer. — Dieci Maria Vittoria et al., Clin Cancer Res

The phase III A-BRAVE trial randomized 466 patients with high-risk early TNBC to adjuvant avelumab or observation after standard therapy. Avelumab improved outcomes only for patients with baseline TILs at least 30%, with 3-year DDFS of 92.0% vs 58.7% (HR 0.20) in high baseline TIL patients versus 70.4% vs 70.1% (HR 0.92) in low baseline TIL patients (interaction p=0.019); baseline TILs were available for 387 patients and residual-disease TILs for 330 patients, with 290 having both. Residual cancer burden was independently prognostic but was not predictive of avelumab benefit.

Clinical bottom line: Baseline TILs, not residual cancer burden, identify the high-risk early TNBC patients who gain from adjuvant avelumab, and TILs should be the stratification variable in the next generation of adjuvant immunotherapy trials.

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🗣️ What People Were Discussing This Week

How these are chosen: filtered for clinical relevance, grouped by the new development discussed, then ordered by engagement (bookmarks and reposts).

Update: ASCO's risk-adapted surveillance guideline meets patient-advocate pushback on ctDNA and individualized follow-up

The guideline sets clinical follow-up annually for low-risk patients, every 6–12 months for intermediate risk, and every 3–6 months for high risk, while advising against routine CT/PET-CT, bone scan, CBC, CEA, CA 15-3, CA 27.29, and ctDNA surveillance outside clinical trials; for selected low-risk patients aged 50 years or older who remain recurrence-free 3 years after breast-conserving surgery, mammography every 1–2 years may be reasonable instead of annual imaging. Patient advocates have challenged this framework: one advocate with oligometastatic TNBC — found at a routine asymptomatic follow-up 5 years after stage I disease, before symptoms developed — reports the updated guidance gives her pause. Advocates note that patients are requesting ctDNA, oncologists are ordering it, and prospective data are needed to guide use of those results rather than simply acknowledging the evidence gap. Commentators frame the guideline as reaffirming that evidence supports smarter surveillance, not more surveillance, while the document also directs a move away from routine surveillance blood panels and toward personalized imaging based on genetics, age, and breast density.

Discussed by: @kazuki_nozawa, @Dr_Oncologista, @JaniceTNBCmets, @K_Yadavir

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Update: after gedatolisib's FDA approval, the debate turns to doublet versus triplet and IV burden

The FDA approved gedatolisib with fulvestrant, with or without palbociclib, for HR-positive, HER2-negative locally advanced or metastatic breast cancer without a detected PIK3CA mutation after progression on endocrine therapy. VIKTORIA-1 was not designed to compare the two gedatolisib arms, yet PFS improvement over fulvestrant was similar with or without palbociclib (HR 0.24 vs HR 0.33, with overlapping 95% CI), and ORR was also similar at 31% vs 28%. The triplet clearly adds toxicity — more than 50% grade 3 neutropenia versus 0% without palbociclib, higher rates of severe stomatitis and nausea, and two grade 5 treatment-related deaths versus none with the doublet. Clinicians identify IV administration as a practical issue and frame the choice of 2 versus 3 drugs as the central challenge until a subcutaneous formulation becomes available.

Discussed by: @kazuki_nozawa, @EladSharonMD, @DFCI_BreastOnc, @MedwatchKate, @PGrivasMDPhD, @Larvol

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CHMP positive opinion for T-DXd plus pertuzumab in first-line HER2-positive metastatic breast cancer

The EMA's CHMP issued a positive opinion recommending trastuzumab deruxtecan plus pertuzumab for the first-line treatment of HER2-positive metastatic breast cancer. Oncologists are debating whether T-DXd plus pertuzumab, supported by DESTINY-Breast09, finally replaces the CLEOPATRA regimen as the first-line standard. Dana-Farber faculty presented institutional recommendations for first-line and maintenance therapy in HER2-positive metastatic breast cancer.

Discussed by: @OncLive, @DFCI_BreastOnc, @DFCI_BreastOnc, @DFCI_BreastOnc

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Gedatolisib plus trastuzumab shows activity in PIK3CA-mutant HER2+ metastatic breast cancer

Approximately 30–40% of HER2-positive breast cancers harbor PIK3CA mutations. In a phase II study published in ESMO Open, gedatolisib plus trastuzumab achieved an ORR of 43.2% with a median PFS of 6 months in heavily pretreated PIK3CA-mutant HER2-positive metastatic breast cancer, with stomatitis as the key toxicity. Clinicians express interest in late-line trials in HER2-positive disease with PIK3CA inhibitors but do not view these combinations as maintenance options given other available choices and toxicity.

Discussed by: @stolaney1, @Dr_ElvinaA, @JaniceTNBCmets

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Somatic BRCA alterations are not clinically equivalent to germline BRCA mutations on CDK4/6 inhibitors

In a large real-world study, shorter CDK4/6 inhibitor treatment duration was observed only in germline BRCA carriers, while patients with somatic BRCA alterations alone had outcomes similar to BRCA-wildtype patients. Somatic BRCA alterations in breast cancer are associated with distinct biological and clinical patterns according to germline BRCA status, published in ESMO Open, and the central question is whether somatic BRCA alterations detected on tumor sequencing should carry the same prognostic weight as germline mutations when planning CDK4/6 inhibitor therapy.

Discussed by: @stolaney1, @stolaney1, @dr_yakupergun

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Camizestrant approved in the EU for emergent ESR1 mutation, but sequential ctDNA testing is the bottleneck

Etcamah (camizestrant) in combination with a CDK4/6 inhibitor was approved in the European Union for ER-positive, HER2-negative advanced breast cancer with an emergent ESR1 mutation and for first-line advanced ER-positive breast cancer. Implementation will require sequential ctDNA testing without progressive disease, which may not be immediately available across Europe. Oncologists note the drug is not yet available in the US and that the serial monitoring requirement represents a concrete infrastructure challenge for European centers.

Discussed by: @stolaney1, @OncLive, @Larvol

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PADMA phase IV: first-line palbociclib plus endocrine therapy beats mono-chemotherapy in high-risk HR+/HER2- disease

PADMA is the first trial to show a significant benefit of palbociclib plus endocrine therapy versus chemotherapy in predominantly postmenopausal patients with HR-positive/HER2-negative metastatic breast cancer and an indication for chemotherapy, with significantly longer time-to-treatment failure and progression-free survival with palbociclib plus endocrine therapy. Reviews of endocrine-resistant HR+/HER2-negative advanced breast cancer now emphasize navigating treatment sequencing across key trials. The result sharpens the question of whether any rationale remains for upfront single-agent chemotherapy in this setting.

Discussed by: @to_be_elizabeth, @OncJournal

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neoPICD: inetetamab plus pyrotinib and chemotherapy in HER2-positive locally advanced disease

In the phase II neoPICD trial, patients with HER2-positive locally advanced breast cancer achieved an objective response rate of 92.6% and 100% disease control with neoadjuvant inetetamab plus pyrotinib plus chemotherapy. A separate ESMO 2026 meta-analysis will address whether adding carboplatin to dual anti-HER2 therapy provides additional benefit in the neoadjuvant treatment of HER2-positive breast cancer. The central debate is whether TKI-plus-antibody neoadjuvant backbones justify displacing taxane-carboplatin plus dual antibody blockade in locally advanced HER2-positive disease.

Discussed by: @ASCOPost, @dr_yakupergun

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EMERALD/JBCRG-M06 final survival: eribulin is a taxane alternative with dual HER2 blockade

The final survival outcomes of JBCRG-M06/EMERALD compared eribulin versus taxane as first-line chemotherapy combined with dual HER2 blockade in patients with HER2-positive locally advanced or metastatic breast cancer. Eribulin achieved comparable long-term survival, with median OS exceeding 6 years and no significant OS difference versus taxanes; ctDNA PIK3CA mutation identified high-risk patients, while HER2 amplification predicted better prognosis. The question for clinicians is whether eribulin can substitute for a taxane alongside trastuzumab and pertuzumab in patients where neuropathy is the dominant concern.

Discussed by: @K_Yadavir, @stolaney1

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CHMP backs sacituzumab govitecan plus pembrolizumab in first-line PD-(L)1-positive metastatic TNBC

CHMP recommended approval of sacituzumab govitecan plus pembrolizumab for treatment-naive, PD-L1-positive metastatic TNBC in the European Union, with the company confirming a positive opinion for the combination in PD-(L)1-positive first-line metastatic triple-negative breast cancer. Updated ASCENT-04 data report PFS of 11.2 vs 7.8 months and a 33% reduction in progression risk for the combination. For patients recurring after neoadjuvant pembrolizumab, clinicians are weighing whether retreatment with immunotherapy plus an ADC is the appropriate first-line choice.

Discussed by: @OncLive, @stolaney1, @DrBarbiOnc

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WSG ADAPT: short preoperative endocrine therapy response predicts outcome in 7,914 patients

In an analysis of the WSG ADAPT-HR+/HER2- and ADAPTcycle trials (N=7,914), aromatase inhibitor use with ovarian function suppression, age over 50 years, low recurrence score, and baseline Ki67 levels independently predicted response to endocrine therapy, with low post-endocrine Ki67 levels associated with improved outcomes in N0-1 HR-positive/HER2-negative early breast cancer. A real-world US electronic health records study of 7,481 patients with HR+/HER2-negative early breast cancer found 5-year distant recurrence risk of 8.8% in high-risk N0 disease and 7.2% in N1 disease. The open clinical question is whether post-endocrine Ki67 after a short preoperative window should guide chemotherapy omission alongside genomic assays.

Discussed by: @OncoAlert, @JaniceTNBCmets

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Clonal hematopoiesis inside tumors is linked to worse survival, especially in breast cancer

Tumor-infiltrating clonal hematopoiesis was detected in 18% of patients with solid tumors and was associated with older age, prior cytotoxic chemotherapy, and reduced overall survival, especially in breast cancer. A companion paper examines the evolution of clonal hematopoiesis during cancer treatment and its impact on outcomes. The clinical question is whether clonal hematopoiesis detected on tumor or ctDNA sequencing should change chemotherapy decisions in older breast cancer patients.

Discussed by: @CathyEngMD, @DFCI_BreastOnc

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ALTTO post-hoc: post-mastectomy radiotherapy benefit in HER2-positive early breast cancer is confined to pN2

A new ALTTO analysis of more than 4,100 patients confirms that post-mastectomy radiotherapy benefit in HER2-positive early breast cancer is clear in patients with 4 or more positive nodes (pN2) — with improved locoregional recurrence, time to distant recurrence, DFS, and OS — while benefit in pN1 is uncertain and no benefit was seen in pN0. In the RAPCHEM prospective registry, 838 patients with cT1-2N1 breast cancer received response-tailored radiotherapy after primary systemic therapy; after 10 years, locoregional recurrence remained low at 2.9% across risk groups, with recurrence-free interval of 79.2% and overall survival of 83.0%. The debate centers on whether nodal radiotherapy in HER2-positive early breast cancer should now be reserved for pN2 disease and guided by nodal response in cN1.

Discussed by: @E_de_Azambuja, @OncoAlert, @AnisToumeh

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🔥 Top Ranked Tweets

OncoAlert @OncoAlert

RT @PGrivasMDPhD: Proud of our amazing leader, @fredhutch @UWMedicine HemOnc Division Chief, Dr. Sara Hurvitz, who led/presented @asco #ASCO26 VIKTORIA-1 trial data that led to @US_FDA approval of gedatolisib in metastatic #breastcancer great news for patients! @DrOmarMian @PTarantinoMD @OncoAlert https://t.co/TAWEPnmfKs

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