Median number of prior therapies for mBC was 3, including fulvestrant (79%), CDK4/6 inhibitors (73%), and chemotherapies (42%). Among 6 pts with ESR1 Y537S, CBR was 83% with 1 PR. Conclusions H3B-6545 450 mg QD had a manageable safety profile and showed preliminary antitumor effect in pts with heavily pretreated, ER+, HER2-negative mBC.
P1/2, N=170, Active, not recruiting, H3 Biomedicine Inc. | Trial completion date: Jun 2023 --> Dec 2022 | Trial primary completion date: Jun 2023 --> Dec 2022
over 2 years ago
Trial completion date • Trial primary completion date
H3B-6545 demonstrates significant activity and superiority over standard-of-care fulvestrant across a panel of ERαWT and ERαMUT palbociclib sensitive and resistant models. In summary, the compelling preclinical activity of H3B-6545 supports its further development for the potential treatment of endocrine therapy-resistant ERα+ breast cancer harboring wild-type or mutant ESR1, as demonstrated by the ongoing clinical trials (NCT03250676, NCT04568902, NCT04288089). H3B-6545 is an ERα covalent antagonist that exhibits encouraging preclinical activity against CDK4/6i naïve and resistant ERαWT and ERαMUT tumors.
over 2 years ago
Preclinical • Journal
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ER (Estrogen receptor) • CDK4 (Cyclin-dependent kinase 4)
Prior therapy in the metastatic setting included fulvestrant (93%), CDK4/6 inhibitors (79%), aromatase inhibitors (64%), and chemotherapy (29%). The combination of H3B-6545 (up to 300 mg dose) and palbociclib (up to 125 mg dose) was well-tolerated and demonstrated preliminary anti-tumor activity in heavily pretreated pts with ER+, HER2- mBC. ClinicalTrials.gov Identifier : NCT04288089.
H3B-6545 has a manageable safety profile and demonstrated single-agent anti-tumor activity in heavily pretreated ER+, HER2- mBC patients. Clinical activity was consistent across the various subgroups. Tumors harboring the constitutionally active ESR1 Y537S mutation may present higher ERα activity, and consequently enrich for luminal A traits and demonstrate greater lineage dependence on ERα.
Prior CDK4/6 inhibitors, aromatase inhibitors, fulvestrant, and chemotherapy were received by 85%, 80%, 72%, and 50% of the pts, respectively . H3B-6545 has a manageable safety profile and demonstrated single-agent anti-tumor activity in heavily pretreated ER+, HER2- mBC patients . Clinical activity was observed in pts with ESR1 mutations.
Prior CDK4/6 inhibitors, fulvestrant, and chemotherapy were received by 87%, 71%, and 54% of the pts, respectively. Median PFS, in all pts and in pts with clonal ESR1 Y537S was 3.7 months and 7.3 months, respectively. Conclusions : H3B-6545 has a manageable safety profile and demonstrated single-agent anti-tumor activity in heavily pretreated ER+, HER2- mBC patients including those with a constitutively active clonal ESR1 Y537S mutation.
H3B-6545 PK profiles in breast cancer patients were well described by a one-compartment disposition model with no significant effect of demographics, liver and renal function. When administered with a high fat meal, H3B-6545 exposure was modestly increased.