vepdegestrant (ARV-471)

P1, N=48, Recruiting, Pfizer | Not yet recruiting --> Recruiting

P1/2, N=67, Recruiting, Pfizer | Trial completion date: Aug 2027 --> Jan 2027 | Trial primary completion date: Feb 2027 --> Jul 2026

P1, N=48, Not yet recruiting, Pfizer

P1, N=16, Recruiting, Pfizer | Not yet recruiting --> Recruiting

P1/2, N=67, Recruiting, Pfizer | Trial completion date: Feb 2027 --> Aug 2027 | Trial primary completion date: Aug 2026 --> Feb 2027

P1, N=12, Recruiting, Pfizer | Not yet recruiting --> Recruiting

P1/2, N=47, Recruiting, Pfizer | Phase classification: P1b/2 --> P1/2 | N=35 --> 47 | Trial completion date: Oct 2027 --> Dec 2026 | Trial primary completion date: Apr 2026 --> Dec 2026

P1/2, N=65, Recruiting, Pfizer | Not yet recruiting --> Recruiting | Trial completion date: Nov 2026 --> Feb 2026 | Trial primary completion date: May 2026 --> Aug 2025

P1/2, N=67, Recruiting, Pfizer | Phase classification: P2 --> P1/2

P1, N=12, Not yet recruiting, Pfizer

P1/2, N=40, Recruiting, Pfizer | Phase classification: P1b/2 --> P1/2 | Trial completion date: Jun 2027 --> Dec 2025

P2, N=67, Recruiting, Pfizer

P1, N=16, Not yet recruiting, Pfizer

P2, N=67, Recruiting, Pfizer | Not yet recruiting --> Recruiting

As of the end of 2022, more than 20 drugs have entered clinical trials, with ARV-471 targeting estrogen receptor (ER) showing remarkable progress by entering phase III clinical studies...In this review, we aimed to update the PROTAC degraders as potential anticancer agents covering articles published in 2022. The design strategies, degradation effects, and anticancer activities were highlighted, which might provide an updated sight to develop novel PROTAC degraders with great potential as anticancer agents as well as favorable drug-like properties.

P1, N=32, Active, not recruiting, Arvinas Estrogen Receptor, Inc. | Recruiting --> Active, not recruiting | Phase classification: P1b --> P1

P2, N=152, Active, not recruiting, Arvinas Inc. | Recruiting --> Active, not recruiting

P1, N=9, Active, not recruiting, Pfizer | Trial primary completion date: Nov 2023 --> Mar 2024

P1, N=12, Completed, Pfizer | Active, not recruiting --> Completed

P1/2, N=65, Not yet recruiting, Pfizer

P1, N=12, Active, not recruiting, Pfizer | Recruiting --> Active, not recruiting

Eligible patients (aged ≥18 years) must have histologically or cytologically confirmed ER+/HER2- locoregionally recurrent or metastatic breast cancer, with no prior treatment in the advanced setting, and no prior treatment in any setting with CDK4/6 inhibitors, vepdegestrant, fulvestrant, elacestrant, or other investigational agents (including novel endocrine therapy, selective ER degraders, selective ER covalent antagonists, and complete ER antagonists). The primary efficacy endpoint of the phase 3 portion is progression-free survival based on blinded independent central review. Enrollment began June 2023 and is ongoing.

The cyclin-dependent kinase (CDK)4/6 inhibitors abemaciclib and ribociclib are approved in combination with an aromatase inhibitor or fulvestrant, or as monotherapy (abemaciclib), for ER+/HER2- advanced or metastatic breast cancer...Vepdegestrant is being evaluated in combination with abemaciclib (sub-study A; NCT05548127), ribociclib (sub-study B; NCT05573555), and samuraciclib (sub-study C)...The phase 2 portion of each sub-study will further evaluate the antitumor activity of the combinations; the primary endpoint is objective response and secondary endpoints include antitumor activity (CBR and DOR), PFS, overall survival, safety, plasma concentration of study drugs, and changes in circulating tumor DNA. Future combination sub-studies will be included in TACTIVE-U.

With 12 months of additional follow-up from the first data report, durable clinical activity with vepdegestrant 200 mg QD was seen in heavily pretreated patients with ER+/HER2- advanced breast cancer, in addition to sustained reduction in circulating mutant ESR1 tumor DNA levels. Vepdegestrant 200 mg QD continued to show a favorable safety profile. The ongoing global, randomized phase 3 VERITAC-2 study (NCT05654623) is evaluating vepdegestrant 200 mg QD vs intramuscular fulvestrant in patients with ER+/HER2- advanced breast cancer after prior combination CDK4/6 inhibitor therapy and endocrine therapy.

In xenograft models, vepdegestrant plus palbo showed substantially greater tumor growth inhibition vs fulvestrant plus palbo, supporting investigation in patients with breast cancer. The combination of vepdegestrant plus palbo showed promising clinical activity in heavily pretreated patients with ER+/HER2- advanced breast cancer who had received extensive prior treatment. The safety profile of vepdegestrant plus palbo was generally consistent with the known safety profiles of the 2 agents except for an increased occurrence of grade 3/4 neutropenia, which was readily managed with laboratory monitoring and dose reductions of palbo. There is an ongoing study lead-in to the global VERITAC-3 study (NCT05909397) that is evaluating 2 doses of palbo (100 mg and 75 mg) in combination with vepdegestrant 200 mg QD to determine the recommended phase 3 combination to compare with letrozole plus palbo as first-line treatment for ER+/HER2- advanced breast cancer.

The primary endpoint, progression-free survival, will be assessed by blinded independent central review in the intention-to-treat population and the ESR1 mutation subpopulation. Secondary outcome measures include overall survival, antitumor activity (objective response rate, duration of response, and clinical benefit rate), safety, and quality of life assessments.

VERITAC-3 will compare vepdegestrant + palbociclib vs letrozole + palbociclib as 1st-line treatment in pts with ER+/HER2- locoregional recurrent/metastatic breast cancer; no prior treatment in the advanced setting; and no prior treatment in any setting with CDK4/6 inhibitors, vepdegestrant, fulvestrant, elacestrant, or other investigational agents. In the phase 3 portion, pts (N≈1130) will be randomized to vepdegestrant + palbociclib or letrozole + palbociclib. The primary endpoint is PFS by BICR.

Conclusions The RP3D of vepdegestrant 200 mg QD was well tolerated in Japanese patients with ER+/HER2- advanced breast cancer. Vepdegestrant will be evaluated in 2 global, randomized phase 3 studies in patients with ER+/HER2- advanced breast cancer: as second/third-line monotherapy in VERITAC-2 (NCT05654623) and as first-line therapy in combination with palbociclib in VERITAC-3 (NCT05909397).

P1b, N=32, Recruiting, Arvinas Estrogen Receptor, Inc. | Trial completion date: Feb 2024 --> Nov 2024 | Trial primary completion date: Aug 2023 --> May 2024

Data support further development of vepdegestrant; the ongoing phase 3 VERITAC-2 study (NCT05654623) is evaluating vepdegestrant 200 mg once daily vs fulvestrant. Table: 390P TRAEs reported in ≥10% of pts overall

P3, N=1180, Recruiting, Pfizer

P2, N=150, Recruiting, Arvinas Inc. | Trial primary completion date: Dec 2023 --> Jul 2024

P1/2, N=215, Recruiting, Arvinas Estrogen Receptor, Inc. | Trial completion date: Feb 2024 --> Sep 2024 | Trial primary completion date: Aug 2023 --> Mar 2024

P1, N=6, Active, not recruiting, Pfizer | Trial completion date: Apr 2023 --> Mar 2024

P1, N=5, Active, not recruiting, Pfizer | Recruiting --> Active, not recruiting

Secondary outcome measures include overall survival, antitumor activity (objective response rate, duration of response, and clinical benefit rate), safety, and quality of life assessments. Clinical trial information: NCT05654623.

ARV-471 combined with abemaciclib or ribociclib showed evidence of synergistic interactions in ER+ breast cancer cells and greater tumor growth inhibition in a xenograft breast cancer model compared with fulvestrant in combination with these agents. Phase 2 further evaluates the antitumor activity of the combinations; the primary endpoint is ORR and secondary endpoints include antitumor activity (CBR and DOR), PFS, overall survival, safety, plasma concentration of study drugs, and changes in circulating tumor DNA. Clinical trial information: NCT05548127, NCT05573555.

The primary endpoint, progression-free survival, will be assessed by blinded independent central review in the intention-to-treat population and the ESR1 mutation sub-population. Secondary outcome measures include overall survival, antitumor activity (objective response rate, duration of response, and clinical benefit rate), safety, and quality of life assessments.

Conclusions After longer follow-up, ARV-471 200 mg QD continued to show clinical activity and was well tolerated in heavily pretreated pts with ER+/HER2- advanced breast cancer. The ongoing phase III VERITAC-2 study (NCT05654623) is evaluating ARV-471 200 mg QD vs fulvestrant.

Everolimus, an inhibitor of mammalian target of rapamycin (mTOR), is approved with exemestane for pts with ER+/HER2- breast cancer after progression on aromatase inhibitors and has shown clinical activity after cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor treatment. The primary endpoints are dose-limiting toxicities to determine the recommended phase II dose for ARV-471 in combination with everolimus, and type, frequency, and severity of adverse events and laboratory abnormalities. Secondary endpoints are preliminary antitumor activity (overall response rate, clinical benefit rate, and duration of response) and pharmacokinetic parameters of ARV-471 plus everolimus.

The primary objective is to evaluate the effect of ARV-471 or anastrozole on Ki-67 expression in tumors after 2 weeks of treatment. Secondary objectives include safety, pathological response (pathologic stage, pathologic complete response rate, and modified preoperative endocrine prognostic index score at the time of surgical resection), and clinical response (breast-conserving surgery rate, radiographic response rate during cycle 6, and best percentage change in caliper measurement on cycle 6 day 1).

P1, N=9, Recruiting, Pfizer | Not yet recruiting --> Recruiting