This phase I trial tests the safety, side effects, and best dose of neratinib in combination
with trastuzumab deruxtecan in treating patients with solid tumors that have spread to other
parts of the body (metastatic) or that cannot be removed by surgery (unresectable), and have
changes in a gene called human epidermal growth factor receptor 2 (HER2). Neratinib is in a
class of medications called kinase inhibitors. It works by blocking the action of an abnormal
protein that signals tumor cells to multiply. This helps slow or stop the spread of tumor
cells. Trastuzumab deruxtecan is in a class of medications called antibody-drug conjugates.
It is composed of a monoclonal antibody, called trastuzumab, linked to a chemotherapy drug,
called deruxtecan. Trastuzumab attaches to HER2 positive tumor cells in a targeted way and
delivers deruxtecan to kill them. Adding neratinib to trastuzumab deruxtecan may be able to
shrink cancer with a change in the HER2 gene.
Description
PRIMARY OBJECTIVE:
I. To assess dose limiting toxicities and determine the maximum tolerated dose (MTD) and
recommended phase 2 dose (RP2D) of neratinib maleate (neratinib) and trastuzumab deruxtecan
(DS-8201a) in patients with advanced solid tumors harboring alterations in HER2 (including
HER2 overexpression/amplification and selected HER2-activating mutations).
SECONDARY OBJECTIVES:
I. To observe and record anti-tumor activity of neratinib and DS-8201a, as measured by
objective response rate (ORR), duration of response (DoR), and progression-free survival
(PFS) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 by investigator
assessment, and overall survival (OS).
II. To assess the safety and tolerability for the combination neratinib and DS-8201a.
III. To assess the effect of neratinib on DS-8201a payload (DXd/MAAA-1181a) tissue
concentration in part 2 at the RP2D chosen in part 1 (and potentially at a lower dose[s] of
neratinib) before and after addition of neratinib to DS-8201a.
IV. To assess the pharmacokinetics of DS-8201a and neratinib in combination.
EXPLORATORY OBJECTIVES:
I. To assess the pharmacodynamic response to neratinib and DS-8201a as measured by markers of
DS-8201a-induced deoxyribonucleic acid (DNA) damage using gammaH2AX, phosphorylated (p)NBS1
immunofluorescence assay (IFA), multiplex multiple reaction monitoring mass spectrometry
(MRM)- based proteomic assay panel of DNA repair response pathway biomarkers, induction of
apoptosis, and HER2 signaling along with other pharmacodynamic (PD) biomarkers such as
cleaved caspase3 (apoptosis) and TOP1CC (target engagement) pending National Clinical
Laboratory Network (NCLN) assay availability.
II. To assess quantifiable HER2 protein expression of pre-treatment or archival tumor
biopsies, and at disease progression in correlation with treatment response.
III. To assess tumor tissue mutation profile pre-treatment and at progression in correlation
with treatment response.
IV. To assess circulating cell-free DNA (cfDNA) mutation profiles pre-treatment, C2D1, and at
progression in correlation with treatment response.
OUTLINE: This is a dose-escalation study of neratinib followed by a dose-expansion (PD)
study.
Patients receive neratinib orally (PO) once daily (QD) on days 1-21 (days 8-21 of cycle 1,
then days 1-21 in cycles thereafter for PD study) of each cycle and trastuzumab deruxtecan
intravenously (IV) over 30-90 minutes on day 1 of each cycle. Cycles repeat every 21 days in
the absence of disease progression or unacceptable toxicity.
After completion of study treatment, patients are followed up every 3 months for at least one
year or until death.