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Program notes — SABCS 2026

Internal pre-meeting working file. Tracks, GS preview, expected late-breakers, anticipated big readouts, key dates. Status: ~7 months pre-meeting (as of May 11, 2026). Almost everything below is speculative until the SABCS program drops in Oct–Nov 2026. Flagged accordingly.

Key dates

Date Event Notes
May 29, 2026 McGuire Award nominations deadline 11:59 PM CST
Jun 1, 2026 Housing registration opens sabcs.org
Jul 13, 2026 Abstract submission deadline 11:59 PM CT; regular abstracts
Sep – Oct 2026 Late-breaking abstract acceptance window Late-breakers typically due ~Oct 1
Oct – Nov 2026 SABCS program release Session grid, GS slate, named lecturers
Nov 2026 Press program briefings open registration Embargoed media briefings during meeting
Dec 8, 2026 (Tue) Meeting opens First GS sessions, McGuire Memorial Lecture historically Day 1
Dec 9, 2026 (Wed) Day 2 GS sessions, mini-symposia, evening Brinker reception
Dec 10, 2026 (Thu) Day 3 GS sessions, late-breaking GS slot historically Thu morning or Fri
Dec 11, 2026 (Fri) Meeting closes Closing GS, year-in-review plenary
Dec 12–15, 2026 ASH 2026 immediately after Back-to-back SABCS → ASH the same week
Jan – Mar 2027 Best of SABCS post-meeting series Synthesis source for themes.md

Sources: SABCS Events page, SABCS 2026 home, AACR SABCS 2026 landing.

Venue & logistics

  • Henry B. Gonzalez Convention Center, 900 E. Market St, San Antonio, TX 78205.
  • ~10,000 attendees from >105 countries.
  • Co-directors: Carlos L. Arteaga (UT Southwestern), Virginia G. Kaklamani (UT Health San Antonio). Program Director: Kate Lathrop.
  • Co-organizers: AACR + UT Health San Antonio + UT Southwestern.
  • Virtual streaming and on-demand replay typically available with registration.

Format & embargo

SABCS sessions historically use:

  • General Sessions (GS1–GS6, two per day × four days = up to 8 GS sessions) — the practice-changing slots, 5–6 abstracts each, with a session-level discussant / chair framing.
  • Mini-Symposia (MS1–MS6+) — translational/basic-science thematic sessions, 6–8 short talks each.
  • Spotlight Discussions / Rapid-Fire Orals (RF1–RF…) — shorter slots.
  • Ongoing Trials (OT) posters — pipeline tracking.
  • Posters (PD / P1–P6) — translational, clinical, prevention, basic biology.
  • Plenary / named lectures: William L. McGuire Memorial Lecture, AACR Distinguished Lectureship in Breast Cancer Research, Brinker Awards (basic + clinical), Susan G. Komen leadership awards.
  • Educational sessions, forums, case discussions for practicing clinicians.

Embargo policy: SABCS abstracts publish to the Cancer Research online supplement and become citable on the day of presentation. Late-breakers in particular embargo until session start (typically 7:00 AM CT day of). Sponsor topline press releases frequently precede the embargo. Detailed 2026 embargo timing not yet posted publicly — to be confirmed once the press-program page goes live (typically Nov 2026).

Anticipated big readouts — pre-meeting watch list

All entries below are speculative, sourced from sponsor 2026 readout guidance (JPM 2026, Q1/Q2 earnings calls), prior-year SABCS slot patterns, ongoing-trial timelines, and analyst preview material. Trial slot assignment to a GS number is unknown until program release. Update post-program.

Top 5 anticipated practice-changing readouts

  1. DESTINY-Breast09 (HER2+ 1L MBC, T-DXd ± pertuzumab vs THP) — Daiichi/AZ. PFS positive per topline (timing per Daiichi/AZ Q1 2026 commentary). The headline of the meeting if PFS magnitude is large — would displace THP as 1L HER2+ SOC and reset the trastuzumab pertuzumab paradigm in place since CLEOPATRA (2012). Cross-link to DESTINY-Breast03 SABCS 2021 (2L reset) and DESTINY-Breast06 ASCO 2024 (HR+/HER2-low/ultralow). [Pre-embargo, sponsor-guided.]
  2. HER2+ adjuvant DESTINY series (DESTINY-Breast05 / -11). DB-05 (T-DXd vs T-DM1 post-neoadj residual) is the KATHERINE-replacement question; DB-11 (T-DXd → THP neoadj vs ddAC-THP) is the HER2+ neoadj reset. Either positive readout reshapes the HER2+ early-stage SOC. Timing risk: DB-11 may slip to 2027. [Pre-embargo, sponsor-guided.]
  3. NATALEE long-term + monarchE 7-yr OS — CDK4/6 adjuvant face-off. monarchE has the brand and the longer follow-up; NATALEE has the broader stage II eligibility and arguably more tolerable schedule. The 2026 readout pair starts ranking these against each other in OS terms (not just iDFS). Practice impact: NCCN adjuvant CDK4/6 stratification by stage / nodal status. [Pre-embargo; topline OS not yet released for either.]
  4. KEYNOTE-756 EFS (HR+ high-risk EBC neoadj pembro + chemo) — MSD. The pCR readout at SABCS 2023 was positive but modest; the practice-changing test is whether pCR translates to EFS. If positive, extends pembro from TNBC neoadj (KEYNOTE-522 SOC) into HR+ high-risk EBC — a much larger population. Cross-link to CheckMate 7FL EFS readout in parallel. [Pre-embargo, follow-up timing per MSD guidance.]
  5. Next-gen oral SERD class definition: EMBER-3 mature + VERITAC-2 (vepdegestrant PROTAC) + persevERA OS context. EMBER-3 mature OS (imlunestrant + abema in ESR1-mut 2L) sets the ceiling; VERITAC-2 validates the PROTAC class; persevERA OS context-sets the SERD-monotherapy ceiling. The composite tells the field whether SERDs become a 1L SOC, stay 2L+ ESR1-mut, or remain a niche. [Pre-embargo; mixed sponsor guidance.]

Secondary watch list

Readout Sponsor Why it matters
post-CDK4/6 sequencing — postMONARCH + INAVO121 + CAPItello-291 OS Lilly / Roche / AZ Ranks 2L options by subset (wild-type, PIK3CA, AKT, ESR1)
TROPION-Breast01 / -02 updates Daiichi / AZ Datopotamab deruxtecan vs sacituzumab class comparison
ASCENT-04 PFS2/OS + ASCENT-03 Gilead TROP2-ADC durability + PD-L1- TNBC 1L extension
DESTINY-Breast12 brain-mets update Daiichi / AZ Confirms T-DXd as brain-mets-active ADC; vs tucatinib (HER2CLIMB)
POSITIVE long-term follow-up IBCSG Pregnancy interruption durability; shared decision-making in young HR+
ctDNA-MRD adjuvant intervention trials (DARE / LEADER / c-TRAK-TN) Academic / cooperative Moves MRD-guided adjuvant from signal to intervention
HER2-low/ultralow assay standardization (mini-symposium) Multi-sponsor Sets eligible-population denominator for T-DXd / Dato-DXd
A-BRAVE final / OptimICE-RD enrollment update Cooperative / NRG Adjuvant IO in TNBC residual disease post-KEYNOTE-522
HER2CLIMB-05 / -02 updates Pfizer / Seagen Tucatinib + chemo / ADC sequencing question
PHERGain / CompassHER2 de-escalation Roche / cooperative HER2+ chemo-free / reduced-chemo neoadj
VERITAC-2 mature Arvinas / Pfizer First PROTAC class validation in oncology
CAPItello-291 OS AZ AKT-i mature data in AKT-altered HR+/HER2-

The major breast pipelines expected to anchor 2026 readouts:

  • AstraZeneca + Daiichi Sankyo — DESTINY-Breast series (T-DXd: DB-09 1L, DB-05/-11 adjuvant, DB-12 brain mets), TROPION-Breast (datopotamab), CAPItello-291 (capivasertib), camizestrant (SERENA series → SABCS readouts on switch / 2L follow-up), Enhertu lifecycle.
  • Lilly — monarchE 7-yr (abemaciclib), EMBER-3/-4 (imlunestrant), postMONARCH, NATALEE-competitor positioning, CDK2/4 selectives in early phase.
  • Pfizer — vepdegestrant (Arvinas-partnered PROTAC, VERITAC-2), HER2CLIMB-05/-02 (tucatinib post-Seagen acquisition), elacestrant (Stemline → Menarini) class competition.
  • Roche / Genentech — INAVO series (inavolisib, PIK3CA-mut), giredestrant (persevERA OS), tucatinib competitive positioning, T-DM1 lifecycle in DB-05 context.
  • MSD — KEYNOTE-756 EFS (HR+ EBC neoadj), KEYNOTE-522 long-term (TNBC neoadj SOC), pembro combinations.
  • Gilead — ASCENT-03/-04 PFS2 (sacituzumab govitecan TROP2-ADC), TROPiCS-02 OS update.
  • Novartis — NATALEE long-term (ribociclib adjuvant), Kisqali franchise lifecycle.
  • Daiichi (separately) / BMS / Menarini-Stemline / Arvinas / Olema — class competition across SERDs, ADCs, AKT-i, PI3K-i, PROTACs.

JPM 2026 day-by-day digests in ../jpm-2026/ flagged most of these toplines as Q4 2026 / SABCS 2026 events in the January 2026 presentations.

Tracks expected to dominate the 2026 corpus

HR+/HER2- MBC

  • Next-gen oral SERDs — camizestrant, imlunestrant, vepdegestrant (PROTAC), elacestrant — class definition vs CDK4/6 + AI SOC.
  • Post-CDK4/6 sequencing — postMONARCH, INAVO121, CAPItello-291 OS, ESR1-mut switch designs.
  • ESR1-mut detection — ctDNA-guided switch (SERENA-6 paradigm extended into 2L).

HER2+ MBC and EBC

  • 1L MBC reset — DESTINY-Breast09 (THP displacement).
  • Adjuvant — DESTINY-Breast05 (T-DM1 niche), DESTINY-Breast11 (neoadj reset).
  • Brain mets — DESTINY-Breast12 update, HER2CLIMB-05.
  • De-escalation — PHERGain, CompassHER2 chemo-free / reduced-chemo regimens.

TNBC

  • TROP2-ADC class — sacituzumab (ASCENT-04 PFS2, ASCENT-03), datopotamab (TROPION-Breast02).
  • Adjuvant post-KEYNOTE-522 — OptimICE-RD, A-BRAVE final, residual-disease intensification.
  • AR+ / LAR subtype — early-phase AR-targeted programs.

Early-stage adjuvant / neoadjuvant

  • CDK4/6 adjuvant — monarchE 7-yr, NATALEE long-term.
  • Neoadjuvant IO in HR+ EBC — KEYNOTE-756 EFS, CheckMate 7FL EFS.
  • ctDNA-MRD-guided adjuvant — DARE, LEADER, c-TRAK-TN.

Biomarker development

  • HER2-low / HER2-ultralow — assay standardization, T-DXd eligibility.
  • ctDNA MRD — assay performance, intervention triggering, FDA / NCCN posture.
  • PIK3CA / AKT1 / PTEN — co-mutation patterns, AKT-i eligibility.

Brain metastases

  • DESTINY-Breast12 confirmatory; HER2CLIMB-05 tucatinib + ADC; intrathecal regimens; leptomeningeal disease early-phase.

Survivorship / prevention / disparities

  • POSITIVE long-term (pregnancy interruption, fertility, ET resumption durability).
  • GLP-1 in breast cancer — obesity / metabolic intersection; cross-link to ASCO 2026 GLP-1 press preview theme.
  • Chemoprevention long-term — anastrozole / tamoxifen extended follow-up.
  • Racial disparities in ADC access / outcomes.

Discussant / session chair watch list

SABCS uses session-level chairs / discussants rather than per-abstract discussants. Names to expect / track (based on prior-year patterns, not yet confirmed for 2026):

  • HR+/HER2-: Hope Rugo (UCSF/UCLA), Sara Tolaney (Dana-Farber), Aditya Bardia (UCLA), Erika Hamilton (Sarah Cannon), Komal Jhaveri (MSK), Matthew Goetz (Mayo).
  • HER2+: Sara Hurvitz (UW Fred Hutch), Ian Krop (Yale), Lisa Carey (UNC), Mafalda Oliveira (Vall d'Hebron).
  • TNBC: Lisa Carey (UNC), Hope Rugo, Joyce O'Shaughnessy (Texas Oncology), Rebecca Dent (NCC Singapore), Sherene Loi (Peter Mac).
  • Adjuvant / EBC: Stephen Johnston (Royal Marsden — monarchE lead), Dennis Slamon (UCLA — NATALEE lead), Pat LoRusso (Yale), Eric Winer (Yale).
  • ctDNA / MRD: Nick Turner (ICR — c-TRAK-TN, plasmaMATCH), Aditya Bardia, Maxine Jochelson / pathology faculty.
  • Brain mets: Nancy Lin (Dana-Farber — HER2CLIMB lead), Carey Anders (Duke).
  • Translational / basic (Mini-Symposia): Carlos Arteaga (UTSW, co-director), Charles Perou (UNC), Jorge Reis-Filho (AstraZeneca, formerly MSK), Mariella De Angelis / global participants.

All names above are pre-confirmation guesses based on prior-year SABCS patterns and disease-group seniority. Will be reconciled against the official program once the session grid posts in Oct–Nov 2026.

What's speculative vs. confirmed

Confirmed (sourced and dated):

  • Meeting dates (Dec 8–11, 2026) and venue (Henry B. Gonzalez Convention Center, San Antonio TX) — SABCS Events page, AACR SABCS 2026.
  • Co-directors and co-organizing institutions — SABCS Symposium Overview.
  • Abstract submission deadline Jul 13, 2026 — sabcs.org.
  • Attendee scale (~10,000 from >105 countries) and program format (GS / MS / Spotlight / OT / posters / named lectures).
  • AACR co-organization confirmed via AACR SABCS landing page.

Speculative — flag before publishing:

  • All trial slot assignments (GS#) — program release Oct–Nov 2026.
  • All pre-embargo result numbers and HRs — pulled from sponsor toplines and analyst previews.
  • Discussant / session chair identities (above watch list).
  • Timing risk for individual readouts (DESTINY-Breast11 in particular may slip to 2027).
  • Late-breaking trial slate (acceptance window Oct 2026).
  • Exact embargo timing for the 2026 press program.

Dead ends (for now)

  • Full abstract text: publishes in Cancer Research supplement on day of presentation. Cannot fabricate.
  • GS session assignments: program drops Oct–Nov 2026. Trial → GS# mapping is purely speculative until then.
  • Discussant / session chair identity: posted with the program.
  • Speaker slide decks: not pre-released. Available via SABCS Virtual or post-presentation press / sponsor coverage.
  • Late-breakers: acceptance window not yet open as of May 11. The most consequential abstracts often arrive via late-breaker (e.g., DESTINY-Breast09 likely-late-breaker).
  • 2026 embargo policy details: press-program page not yet live.

Sources