Poster viewing and lunch

201P - Trilaciclib combined with sacituzumab govitecan (SG) in metastatic triple-negative breast cancer (mTNBC): Preliminary phase 2 results (ID 405)

Lecture Time
12:15 - 12:15
Session Name
Poster viewing and lunch
Room
Exhibition area
Date
Fri, 12.05.2023
Time
12:15 - 13:00
Speakers
  • Lasika Seneviratne (Los Angeles, CA, United States of America)
Authors
  • Lasika Seneviratne (Los Angeles, CA, United States of America)
  • Kathleen K. Harnden (Fairfax, VA, United States of America)
  • Mabel Mardones (Denver, CO, United States of America)
  • Sibel Blau (Puyallup and Tacoma, WA, United States of America)
  • Amanda Gillespie-Twardy (Roanoke, VA, United States of America)
  • Michael A. Danso (Norfolk, VA, United States of America)
  • David Berz (Los Angeles, CA, United States of America)
  • Delia Guaqueta (Hollywood, FL, United States of America)
  • John Schwerkoske (Woodbury, MN, United States of America)
  • Joyce O'Shaughnessy (Dallas, United States of America)
  • Debra Patt (Austin, TX, United States of America)
  • Aditya Bardia (Boston, MA, United States of America)
  • Andrew Beelen (Research Triangle Park, NC, United States of America)
  • Taofik Oyekunle (Research Triangle Park, NC, United States of America)
  • Vanessa Dell (Research Triangle Park, NC, United States of America)
  • Sara A. Hurvitz (Santa Monica, CA, United States of America)

Abstract

Background

Trilaciclib protects CDK4/6-dependent hematopoietic stem and progenitor cells during chemotherapy (CT; myeloprotection). SG is an antibody–drug conjugate indicated to treat pts with mTNBC. In the phase III ASCENT trial, SG significantly extended survival vs single-agent CT but was associated with increased neutropenia (any grade [G], 63% vs 43%; G3/4, 51% vs 33%) and diarrhea (any G, 59% vs 12%; G3/4, 10% vs < 1%; Bardia et al. N Engl J Med. 2021). In a phase II trial of trilaciclib prior to CT in mTNBC, trilaciclib modulated antitumor immunity (Tan et al. Clin Cancer Res. 2022). Administering trilaciclib prior to SG may improve antitumor efficacy and minimize myelotoxicity in pts with mTNBC. We report preliminary safety and efficacy results from a phase II, single-arm trial of trilaciclib in pts receiving SG for mTNBC (NCT05113966).

Methods

Eligible adult pts (≥ 2 prior systemic therapies [≥ 1 in the metastatic setting]; measurable disease; confirmed hormone receptor-/HER2-negative status; ECOG PS 0/1) receive intravenous trilaciclib 240 mg/m2 prior to SG 10 mg/kg on Days 1 and 8 of each 21-day cycle until disease progression/toxicity. Tumor assessments occur at screening, every 6 weeks to week 36, then every 9 weeks until disease progression/subsequent anticancer therapy. Endpoints include antitumor efficacy, myeloprotection, and safety/tolerability.

Results

As of January 17, 2023, 26 (of 45 planned) female pts had been enrolled and completed a median (range) of 4 (2–15) cycles. Pts had received a median of 2 (2–5) prior lines of therapy, including taxanes (n = 20) and immune checkpoint inhibitors (n = 18). See table; objective response rate by PD-L1 status will be presented. One pt had AEs that led to discontinuation of both study drugs.

AEs (safety population; N = 26) Any G, n (%) G3/4, n (%)
Selected AEs by preferred term (PT) FatigueNauseaAlopeciaConstipationDiarrhea Hematological AEs by collapsed PT NeutropeniaAnemiaLeukopenia -11 (42)10 (39)8 (31)8 (31)8 (31)-6 (23)2 (8)4 (15) -01 (4)001 (4)-4 (15)03 (12)
Best overall response (response-evaluable population; N = 20) n (%) 95% CI
Complete response (CR)Partial response (PR)Stable disease (SD)Progressive disease (PD) Objective response rate (CR + PR) Clinical benefit rate (CR + PR + SD24wks) 05 (25)*10 (50)5 (25)*5 (25)*7 (35) -8.7–49.127.2–72.88.7–49.18.7–49.115.4–59.2

∗PR, n = 6 (30%); 1 pt with PR continued therapy after PD (21% increase in sum of longest diameters)

Conclusions

Preliminary data suggest trilaciclib prior to SG has the potential to reduce the rate and severity of multiple AEs compared with results from trials of SG alone, and warrant its continued evaluation.

Clinical trial identification

NCT05113966.

Editorial acknowledgement

Medical writing assistance was provided by Philip Reardon, PhD, from Alligent Europe (Envision Pharma Group), funded by G1 Therapeutics, Inc.

Legal entity responsible for the study

G1 Therapeutics, Inc.

Funding

G1 Therapeutics, Inc.

Disclosure

L. Seneviratne: Financial Interests, Personal, Invited Speaker, Payment or honararia for lectures, presentations, speakers bureaus, manuscript writing or educational event: Novartis; Financial Interests, Personal, Advisory Board: AstraZeneca. K.K. Harnden: Financial Interests, Personal, Invited Speaker: Merck, Daiichi Sankyo, AstraZeneca, Seagen, Eisai. M. Mardones: Financial Interests, Personal, Other, Gilead Sciences Payments for consultant work: Gilead Sciences. M.A. Danso: Financial Interests, Personal, Advisory Role: Novartis, Pfizer, Immunomedics, Seattle Genetics; Financial Interests, Personal, Other, Honoraria: Amgen. D. Berz: Financial Interests, Personal, Other, Consulting fees: Jazz Pharma, Sun Pharma; Financial Interests, Personal, Invited Speaker: Jazz Pharma, Sun Pharma, Mirati, EMD Serono, Caris Life Science, AstraZeneca; Financial Interests, Personal, Other, Support for attending meetings and/or travel: Jazz Pharma, Sun Pharma, Mirati, EMD Serono, Caris Life Science, AstraZeneca. J. O'Shaughnessy: Financial Interests, Personal, Advisory Role: AbbVie Inc., Agendia, Amgen Biotechnology, Aptitude Health, AstraZeneca, Bayer, Bristol Myers Squibb, Celgene Corporation, Clovis Oncology, Daiichi Sankyo, Eisai, G1 Therapeutics, Genentech, Gilead Sciences, GRAIL, Halozyme Therapeutics, Heron Therapeutics, Immunomedics, Ipsen Biopharmaceuticals, Lilly, Merck, Myriad, Nektar Therapeutics, Novartis, Pfizer, Pharmacyclics, Pierre Fabre Pharmaceuticals, Puma Biotechnology, Prime Oncology, Roche, Samsung Bioepis, Sanofi, Seagen, Syndax Pharmaceuticals, Taiho Oncology, Takeda, Synthon; Financial Interests, Personal, Other, Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: AbbVie Inc., Agendia, Amgen Biotechnology, Aptitude Health, AstraZeneca, Bayer, Bristol Myers Squibb, Celgene Corporation, Clovis Oncology, Daiichi Sankyo, Eisai, G1 Therapeutics, Genentech, Gilead Sciences, GRAIL, Halozyme Therapeutics, Heron Therapeutics, Immunomedics, Ipsen Biopharmaceuticals, Lilly, Merck, Myriad, Nektar Therapeutics, Novartis, Pfizer, Pharmacyclics, Pierre Fabre Pharmaceuticals, Puma Biotechnology, Prime Oncology, Roche, Samsung Bioepis, Sanofi, Seagen, Syndax Pharmaceuticals, Taiho Oncology, Takeda, Synthon. D. Patt: Financial Interests, Personal, Invited Speaker: Ideology, Pfizer, DSI; Financial Interests, Personal, Member of the Board of Directors: ASCO; Financial Interests, Personal, Leadership Role: Community College Alliance. A. Bardia: Financial Interests, Personal, Advisory Board: Pfizer, Novartis, Genentech, Merck, Sanofi, Eisai, Lilly, Mersana, AstraZeneca/Daiichi, Menarini, Gilead; Financial Interests, Personal, Royalties: UpToDate; Financial Interests, Institutional, Invited Speaker: Genentech, Novartis, Pfizer, Merck, Sanofi, Radius Health, Immunomedics/Gilead, Daiichi Pharma/AstraZeneca, Eli Lilly.; Non-Financial Interests, Principal Investigator: Gilead, Mersana, AstraZeneca/Daiichi, Novartis, Pfizer, Genentech, Lilly, Merck, Sanofi. A. Beelen: Financial Interests, Institutional, Funding, Funding to support all aspects of the study: G1 Therapeutics Inc.; Financial Interests, Personal, Stocks/Shares: G1 Therapeutics Inc.; Financial Interests, Personal, Full or part-time Employment: G1 Therapeutics Inc. T. Oyekunle: Financial Interests, Institutional, Funding, Funding to support all aspects of the study: G1 Therapeutics Inc.; Financial Interests, Personal, Stocks/Shares: G1 Therapeutics Inc.; Financial Interests, Personal, Full or part-time Employment: G1 Therapeutics Inc. V. Dell: Financial Interests, Institutional, Funding: G1 Therapeutics Inc.; Financial Interests, Institutional, Other, Medical writing: G1 Therapeutics Inc.; Financial Interests, Personal, Stocks/Shares: G1 Therapeutics Inc.; Financial Interests, Personal, Full or part-time Employment: G1 Therapeutics Inc. S.A. Hurvitz: Financial Interests, Personal, Other, Travel, Accommodations, Expenses: Lilly; Financial Interests, Personal, Other: Roche, Pfizer; Financial Interests, Personal, Stocks/Shares, An Immediate Family Member: Ideal Implant; Financial Interests, Personal, Invited Speaker, An Immediate Family Member: ROM Tech; Financial Interests, Personal, Funding, Honoraria: Daiichi Sankyo/AstraZeneca; Financial Interests, Institutional, Funding: Genentech/Roche, Novartis, GlaxoSmithKline, Sanofi, Pfizer, Amgen, OBI Pharma, Puma Biotechnology, Dignitana, Bayer, Biomarin, Lilly, Merrimack, Cascadian Therapeutics, Seattle Genetics, Daiichi Sankyo, Macrogenics, Ambryx, Immunomedics, Pieris Pharmaceuticals, Radius Health, Arvinas, Zymeworks, Gilead Sciences, Phoenix Molecular Designs, CytomX Therapeutics, Samumed, Dantari, Orin, Greenwich LifeSciences, AstraZeneca/Daiichi Sankyo, G1 Therapeutics. All other authors have declared no conflicts of interest.

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