On December 8, 2020 Seagen Inc. (Nasdaq:SGEN) reported the presentation of new data from TUKYSA (tucatinib), its HER2-positive metastatic breast cancer therapy, at the San Antonio Breast Cancer Symposium (SABCS) Virtual Symposium, taking place December 8-11, 2020 (Press release, Seagen, DEC 8, 2020, View Source [SID1234572426]). Nine abstracts – including two spotlight posters – highlight the company’s commitment to addressing unmet needs in breast cancer.
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"Following this year’s FDA approval of TUKYSA, we continue to broadly study if more patients may benefit from this important medicine," said Roger Dansey, M.D., Chief Medical Officer at Seagen. "Data presented at the meeting from the HER2CLIMB trial demonstrate TUKYSA’s efficacy regardless of patients’ hormone receptor status, while other clinical and preclinical findings provide new insights about TUKYSA’s potential to help patients living with HER2-positive metastatic breast cancer."
Highlights for key data presentations at the meeting include:
Efficacy Outcomes by Hormone Receptor Status from HER2CLIMB Trial
Outcomes for TUKYSA (tucatinib) in combination with trastuzumab and capecitabine in patients with HER2-positive metastatic breast cancer from the pivotal HER2CLIMB trial by hormone receptor (HR) status will be featured in a spotlight poster (Abstract #PD3-08). Results will be presented by Erika P. Hamilton, M.D., Director, Breast Cancer and Gynecologic Cancer Research Program at the Sarah Cannon Research Institute.
As previously reported, the addition of TUKYSA to trastuzumab and capecitabine resulted in clinically meaningful improvements in overall survival (OS), progression-free survival (PFS) and objective response rate (ORR) compared to the addition of placebo. The new exploratory analyses presented at SABCS demonstrated that the PFS, OS and ORR improvements with TUKYSA were observed consistently across hormone receptor status subgroups, including in patients with brain metastases.
SABCS 2020 Data Presentations for Seagen Medicines and Pipeline Agents:
Below are presentation details related to TUKYSA and the investigational agent ladiratuzumab vedotin at SABCS. Published abstracts can be found here. Poster presentations will be available on December 9, 2020.
Abstract Title
Abstract No.
Presentation
Type / Date
Presenter
Tucatinib versus placebo in combination with trastuzumab and capecitabine for patients with locally advanced unresectable or HER2-positive metastatic breast cancer (HER2CLIMB): outcomes by hormone receptor status
#PD3-08
Spotlight Poster Discussion 3 – Wednesday, Dec. 9 from 6:45 – 7:45 p.m. CT
E. Hamilton
Impact of tucatinib on health-related quality of life in patients with HER2+ metastatic breast cancer with stable and active brain metastases
#PD13-04
Spotlight Poster Discussion 13 – Friday, Dec. 11 from 1 – 2:15 p.m. CT
A. Wardley
Tucatinib favourably modulates the immune microenvironment and synergises with anti-PD1 therapy in a trastuzumab resistant HER2+ murine model
#PS10-04
Poster Session 10 / Wednesday, Dec. 9 at 8 a.m. CT
R. Li
Tucatinib potentiates the activity of the antibody-drug conjugate T-DM1 in preclinical models of HER2-positive breast cancer
#PS10-08
Poster Session 10 / Wednesday, Dec. 9 at 8 a.m. CT
A. Kulukian
Real world treatment patterns and healthcare resource utilization among HER2+ metastatic breast cancer patients with and without brain metastases: a retrospective cohort study
#PS14-15
Poster Session 14 / Wednesday, Dec. 9 at 8 a.m. CT
C. Ike
Interim safety and efficacy analysis of phase IB/II clinical trial of tucatinib, palbociclib and letrozole in patients with hormone receptor and HER2-positive metastatic breast cancer
#PS10-03
Poster Session 10 / Wednesday, Dec. 9 at 8 a.m. CT
E. Shagisultanova
Trials-in-Progress
HER2CLIMB-02: A randomized, double-blind, phase 3 study of tucatinib or placebo with T-DM1 for unresectable locally-advanced or metastatic HER2+ breast cancer
#OT-28-01
Ongoing Trials Posters / Wednesday, Dec. 9 at 8 a.m. CT
S. Hurvitz
SGNLVA-001: a phase 1 open-label dose escalation and expansion study of SGN-LIV1A administered weekly in breast cancer
#OT-03-03
Ongoing Trials Posters / Wednesday, Dec. 9 at 8 a.m. CT
H.C. Beckwith
About TUKYSA (tucatinib)
TUKYSA is an oral medicine that is a tyrosine kinase inhibitor of the HER2 protein. In vitro (in lab studies), TUKYSA inhibited phosphorylation of HER2 and HER3, resulting in inhibition of downstream MAPK and AKT signaling and cell growth (proliferation), and showed anti-tumor activity in HER2-expressing tumor cells. In vivo (in living organisms), TUKYSA inhibited the growth of HER2-expressing tumors. The combination of TUKYSA and the anti-HER2 antibody trastuzumab showed increased anti-tumor activity in vitro and in vivo compared to either medicine alone. In the U.S., TUKYSA is approved in combination with trastuzumab and capecitabine for adult patients with advanced unresectable or metastatic HER2-positive breast cancer, including patients with brain metastases (disease that has spread to the brain), who have received one or more prior anti-HER2-based regimens in the metastatic setting. TUKYSA is approved in the U.S., Switzerland, Canada, Singapore and Australia and is under review in the European Union. As part of a strategic collaboration announced in September 2020 with Merck, known as MSD outside the United States and Canada, Merck has exclusive rights to commercialize TUKYSA in Asia, the Middle East and Latin America and other regions outside of the U.S., Canada and Europe.
U.S. Important Safety Information
Warnings and Precautions
Diarrhea – TUKYSA can cause severe diarrhea including dehydration, hypotension, acute kidney injury, and death. In HER2CLIMB, 81% of patients who received TUKYSA experienced diarrhea, including 12% with Grade 3 diarrhea and 0.5% with Grade 4 diarrhea. Both patients who developed Grade 4 diarrhea subsequently died, with diarrhea as a contributor to death. The median time to onset of the first episode of diarrhea was 12 days and the median time to resolution was 8 days. Diarrhea led to dose reductions of TUKYSA in 6% of patients and discontinuation of TUKYSA in 1% of patients. Prophylactic use of antidiarrheal treatment was not required on HER2CLIMB.
If diarrhea occurs, administer antidiarrheal treatment as clinically indicated. Perform diagnostic tests as clinically indicated to exclude other causes of diarrhea. Based on the severity of the diarrhea, interrupt dose, then dose reduce or permanently discontinue TUKYSA.
Hepatotoxicity – TUKYSA can cause severe hepatotoxicity. In HER2CLIMB, 8% of patients who received TUKYSA had an ALT increase >5 × ULN, 6% had an AST increase >5 × ULN, and 1.5% had a bilirubin increase >3 × ULN (Grade ≥3). Hepatotoxicity led to dose reduction of TUKYSA in 8% of patients and discontinuation of TUKYSA in 1.5% of patients.
Monitor ALT, AST, and bilirubin prior to starting TUKYSA, every 3 weeks during treatment, and as clinically indicated. Based on the severity of hepatotoxicity, interrupt dose, then dose reduce or permanently discontinue TUKYSA.
Embryo-Fetal Toxicity – TUKYSA can cause fetal harm. Advise pregnant women and females of reproductive potential risk to a fetus. Advise females of reproductive potential, and male patients with female partners of reproductive potential, to use effective contraception during TUKYSA treatment and for at least 1 week after the last dose.
Adverse Reactions
Serious adverse reactions occurred in 26% of patients who received TUKYSA. Serious adverse reactions in ≥2% of patients who received TUKYSA were diarrhea (4%), vomiting (2.5%), nausea (2%), abdominal pain (2%), and seizure (2%). Fatal adverse reactions occurred in 2% of patients who received TUKYSA including sudden death, sepsis, dehydration, and cardiogenic shock.
Adverse reactions led to treatment discontinuation in 6% of patients who received TUKYSA; those occurring in ≥1% of patients were hepatotoxicity (1.5%) and diarrhea (1%). Adverse reactions led to dose reduction in 21% of patients who received TUKYSA; those occurring in ≥2% of patients were hepatotoxicity (8%) and diarrhea (6%).
The most common adverse reactions in patients who received TUKYSA (≥20%) were diarrhea, palmar-plantar erythrodysesthesia, nausea, fatigue, hepatotoxicity, vomiting, stomatitis, decreased appetite, abdominal pain, headache, anemia, and rash.
Lab Abnormalities
In HER2CLIMB, Grade ≥3 laboratory abnormalities reported in ≥5% of patients who received TUKYSA were: decreased phosphate, increased ALT, decreased potassium, and increased AST. The mean increase in serum creatinine was 32% within the first 21 days of treatment with TUKYSA. The serum creatinine increases persisted throughout treatment and were reversible upon treatment completion. Consider alternative markers of renal function if persistent elevations in serum creatinine are observed.
Drug Interactions
Strong CYP3A or Moderate CYP2C8 Inducers: Concomitant use may decrease TUKYSA activity. Avoid concomitant use of TUKYSA.
Strong or Moderate CYP2C8 Inhibitors: Concomitant use of TUKYSA with a strong CYP2C8 inhibitor may increase the risk of TUKYSA toxicity; avoid concomitant use. Increase monitoring for TUKYSA toxicity with moderate CYP2C8 inhibitors.
CYP3A Substrates: Concomitant use may increase the toxicity associated with a CYP3A substrate. Avoid concomitant use of TUKYSA where minimal concentration changes may lead to serious or life-threatening toxicities. If concomitant use is unavoidable, decrease the CYP3A substrate dosage.
P-gp Substrates: Concomitant use may increase the toxicity associated with a P-gp substrate. Consider reducing the dosage of P-gp substrates where minimal concentration changes may lead to serious or life-threatening toxicity.
Use in Specific Populations
Lactation: Advise women not to breastfeed while taking TUKYSA and for at least 1 week after the last dose.
Renal Impairment: Use of TUKYSA in combination with capecitabine and trastuzumab is not recommended in patients with severe renal impairment (CLcr < 30 mL/min), because capecitabine is contraindicated in patients with severe renal impairment.
Hepatic Impairment: Reduce the dose of TUKYSA for patients with severe (Child-Pugh C) hepatic impairment.