bavdegalutamide (ARV-110)

Androgen receptor (AR) signaling is the principal driver of prostate cancer, and drugs that target this pathway (e.g., abiraterone and enzalutamide) are standard treatments for metastatic hormone-sensitive prostate cancer and metastatic castration-resistant prostate cancer (mCRPC). These promising preclinical data supported clinical development of bavdegalutamide as a potential treatment for patients with prostate cancer. Bavdegalutamide was the first PROTAC protein degrader to enter human clinical trials, specifically in patients with mCRPC in a phase 1/2 study (NCT03888612).

We developed and validated a sensitive and rapid liquid chromatography-tandem mass spectrometry method to quantify vepdegestrant in rodent plasma using bavdegalutamide (formerly ARV-110) as an internal standard. In liver microsomes, vepdegestrant exhibited moderate stability in rats but was stable in mice, dogs, and humans. These findings enhance the understanding of pharmacokinetic properties of vepdegestrant supporting further development of PROTAC drugs.

PROTACs, DAARIs, and anitens represent novel and promising AR-targeting therapeutics that may become an important part of prostate cancer treatment in the future. Elucidating mechanisms of resistance, including ability of these agents to target full length AR, may yield further insights into maximal therapeutic efficacy aimed at silencing AR signaling.

Here, the study reports a novel cereblon-based AR degrader, UBX-390, and demonstrates its superior activity over established AR degraders, such as ARV-110 or ARCC-4, in prostate cancer cells under short- and long-term treatment conditions. UBX-390 suppresses chromatin binding and gene expression of AR and demonstrates substantial efficacy in the degradation of AR mutants in patients with treatment-resistant prostate cancer. UBX-390 is presented as an optimized AR degrader with remarkable potential for treating castration-resistant prostate cancer.

We also assessed the efficacy of target protein degraders (TPDs), such as ARV-110 and ARV-667, in both models, and the corresponding validation data are also included here.

P1, N=40, Active, not recruiting, Arvinas Androgen Receptor, Inc. | Trial primary completion date: Apr 2024 --> Jul 2024

Thalidomide, lenalidomide, and pomalidomide, these three CRBN-binding MGDs, were clinically approved to treat several intractable diseases (including multiple myeloma). Several other MGDs and CRBN-based PROTACs (ARV-110 and AVR-471) are undergoing clinical trials. In addition, several new related technologies regarding PROTACs and MGDs have also been developed, and achievements of protein degraders impact not only therapeutic fields but also basic biological science. In this article, I introduce the history of protein degraders, from the development of thalidomide to the latest PROTACs and related technologies.

P1, N=40, Active, not recruiting, Arvinas Androgen Receptor, Inc. | Phase classification: P1b --> P1 | Trial completion date: Jun 2024 --> Dec 2025 | Trial primary completion date: Nov 2023 --> Apr 2024

P1/2, N=250, Active, not recruiting, Arvinas Androgen Receptor, Inc. | Recruiting --> Active, not recruiting

There were no grade ≥4 treatment-related adverse events (TRAEs) with 420 mg bavdeg (n=158 across phase 1/2); any grade TRAEs reported in ≥20% of pts were nausea (54%; 1% grade 3), fatigue (35%; 1% grade 3), vomiting (31%; 1% grade 3), diarrhea (25%; 2% grade 3) and decreased appetite (23%; 0 grade 3). Conclusions Bavdeg had encouraging efficacy in post-NHA pts with mCRPC and AR 878/875 or any AR missense LBD mutation (excluding AR L702H alone) and was tolerable; these pt populations will be analyzed in a phase 3 study of bavdeg.

P1/2, N=250, Recruiting, Arvinas Androgen Receptor, Inc. | Trial completion date: Oct 2023 --> Nov 2024 | Trial primary completion date: Feb 2023 --> Mar 2024

Since the progression of ARV-110 (PROTAC for PC) into clinical phases, the focus of research has quickly shifted to protein degraders targeting prostate cancer...We also delve into the underlying pathophysiology of the disease and explain the structural design and linkerology strategies for PROTAC molecules. Additionally, we touch on the various targets for PROTAC in prostate cancer, including the androgen receptor (AR) and other critical oncoproteins, and discuss the future prospects and challenges in this field.

The androgen deprivation therapy (ADT) alone and its combination with hormone therapy that block AR signaling (e.g., enzalutamide or abiraterone) are effective treatments for advanced prostate cancer. No animal was found dead or moribund and no test article-related changes in clinical signs,body weights, food consumption, ophthalmologic examinations, clinical pathology parameters, sperm analysis, urinalysis, organ weights, histopathology. In conclusion, HSK38008 is a promising oral AR-V7 degrader with better efficacy than enzalutamide and ARV-110 in AR and AR-V7 positive, and potential AR mutants mCRPC.

Especially, the first PROTAC to enter the clinic, ARV-110, has shown good clinical effects in patients with mCRPC. This fully demonstrates the high clinical value of PROTAC strategy in treatment of human diseases. Here, we summarized the recent advances in the development of these potential clinical-stage PROTAC AR degraders.

"Today Foundation Medicine, Inc...announced a collaboration with Arvinas, Inc., to develop FoundationOne®Liquid CDx as a companion diagnostic for use with Arvinas’ bavdegalutamide (ARV-110), an investigational novel PROTAC® protein degrader targeting the androgen receptor (AR). Arvinas’ bavdegalutamide is being developed for the potential treatment of men with metastatic castration resistant prostate cancer (mCRPC) who have progressed on existing therapies."

The most clinically advanced proteolysis-targeting chimera, bavdegalutamide, seems to work best against two molecularly defined subtypes of advanced prostate cancer. According to phase I/II trial data presented at the 2022 American Society of Clinical Oncology Genitourinary Cancers Symposium, the androgen receptor degrader most commonly shows antitumor activity among patients with T878X or H875Y mutations.

Prior treatment with enzalutamide, apalutamide, darolutamide, or experimental AR-directed therapies is not permitted. Bavdegalutamide, abiraterone, and a corticosteroid will be administered daily in 28-day cycles. Primary objectives are to evaluate the safety and tolerability of bavdegalutamide plus abiraterone and determine the recommended phase 2 dose and schedule of this combination (based on the incidence of first-cycle dose-limiting toxicities and the frequency and severity of adverse events and laboratory abnormalities).

In phase 1, pts with mCRPC and disease progression after =2 prior therapies (enzalutamide and/or abiraterone required) received ARV-110 orally once or twice daily (QD or BID) in sequential cohorts (3 + 3 dose escalation design). ARV-110, a novel AR protein degrader, demonstrates clinical activity in a post-NHA, heavily pretreated mCRPC pt population, with greatest PSA50 activity and RECIST responses in pts with AR T878 and/or H875 mutations, likely representing a particularly ARV-110–sensitive population. ARV-110 merits further investigation in pts with mCRPC.

In phase 1, pts with mCRPC and disease progression after =2 prior therapies (enzalutamide and/or abiraterone required) received ARV-110 orally once or twice daily (QD or BID) in sequential cohorts (3 + 3 dose escalation design). ARV-110, a novel AR protein degrader, demonstrates clinical activity in a post-NHA, heavily pretreated mCRPC pt population, with greatest PSA50 activity and RECIST responses in pts with AR T878 and/or H875 mutations, likely representing a particularly ARV-110–sensitive population. ARV-110 merits further investigation in pts with mCRPC.

Currently, ARV-110, an orally small molecule PROTAC was designed to specifically target Androgen receptor (AR), firstly enters clinical phase I trials for the treatment of metastatic castration-resistant prostate cancer, which turns a new avenue for the development of PROTAC. We herein provide a detail summary on the latest one year progress of PROTAC target various proteins and elucidate the advantages of PROTAC technology. Finally, the potential challenges of this vibrant field are also discussed.

Preliminary clinical data for ARV-110, a proteolysis-targeting chimera that flags the androgen receptor for degradation, indicate that the drug is safe and shows some efficacy in men with metastatic castration-resistant prostate cancer.

1 of 18 pts experienced a DLT (280 mg) of Grade (Gr) 4 elevated AST/ALT followed by acute renal failure while taking rosuvastatin (ROS)...Prior therapy in both pts included ENZ and ABI, chemotherapy, bicalutamide and radium-223 plus other regimens... To date, ARV-110 has an acceptable safety profile. Concurrent ROS is now prohibited. MTD has not yet been established; determination of RP2D continues.