Open Menu
Meetings & Education
Meetings & Education
Research & Data
Practice & Patients
Career Development
News & Initiatives
Get Involved
An oral prostate cancer RIPTACÂ therapeutic in phase 1 for metastatic castrate resistant prostate cancer (mCRPC).
Background:
New therapies are urgently needed to treat prostate cancer, especially for patients progressing on existing drugs that inhibit the activity of the Androgen Receptor (AR) (e.g. Androgen Receptor Pathway Inhibitors (ARPIs)). Metastatic Castration-Resistant Prostate Cancer (mCRPC) is a more aggressive stage of the disease, characterized by increased AR expression and signaling. To address this unmet medical need, we have developed a Regulated Induced Proximity Targeting Chimera (RIPTAC™) Therapeutic HLD-0915. HLD-0915 is a heterobifunctional small molecule that leverages full length AR (FL-AR) expression in tumor cells to form a trimeric complex with an Essential Protein (EP) needed for cell survival. This results in EP loss of function in prostate cancer cells and a selective antitumor effect. HLD-0915 activity requires only the presence of FL-AR and retains activity regardless of whether there are AR or non-AR aberrations that may otherwise serve as drivers of disease. Preclinically, HLD-0915 treatment results in tumor shrinkage and PSA declines following oral dosing in murine models of castration-resistant and ARPI-resistant forms of the disease, while delivering a favorable therapeutic index. The Phase 1 trial in mCRPC will investigate safety and early signs of efficacy in the intended patient population.
Methods:
This first-in-human, multicenter, open label Phase 1/2 study evaluates the safety, tolerability, and clinical activity of HLD-0915 in patients with mCRPC. Phase 1 consists of monotherapy dose levels employing a Bayesian Optimal Interval (BOIN) design with each dose level starting with a minimum of 3 patients per cohort with the primary objectives of defining the maximal tolerated dose and/or recommended dose for expansion and characterizing safety and tolerability of HLD-0915. This study also aims to characterize the PK profile and assess clinical activity by PSA declines and objective response rate per RECIST and will explore ctDNA, tumor cell genetics, and PD biomarkers. Patients with progressive mCRPC who may or may not have received prior novel antiandrogen therapy, a taxane, or PSMA targeted radioligand will be enrolled. Cohort 1 enrollment begins in January 2025.
The Phase 2 portion of the study will confirm the RP2D and clinical activity in up to 3 cohorts which will be decided in the future based on emerging data.
Disclaimer
This material on this page is ©2025 American Society of Clinical Oncology, all rights reserved. Licensing available upon request. For more information, please contact licensing@asco.org
Author Details
Katherine Kayser-Bricker
Halda Therapeutics, New Haven, CT
Authors chevron_right
Associated Organizations chevron_right
Abstract Details
Meeting
2025 ASCO Annual Meeting
Session Type
Poster Session
Session Title
Genitourinary Cancer—Prostate, Testicular, and Penile
Track
Genitourinary Cancer—Prostate, Testicular, and Penile
View MoreAbstract Disclosure
open_in_new
Your Privacy
ASCO is committed to transparency regarding our websites and the ways we process data. When you visit our site, we may store or retrieve information on your browser, mostly in the form of cookies. This information might be about you, your preferences, your location, or your device and is mostly used to make the site work as you expect it to and to personalize your web experience with us.
Because we respect your right to privacy, you can choose not to allow some or all types of cookies. Click on the different category headings to find out more about the types of cookies used on our websites and change your default settings to match your preferences. Please read these carefully. Blocking some types of cookies may impact your experience on the site, including our ability to personalize the content you receive from us.
For a full explanation of the personal and non-personal information we collect on our site, including how we use that information and your rights regarding that information, please review our Privacy Policy. Use of our website is also subject to our Terms of Use.
Allow All
Manage Consent Preferences
Essential Website Cookies
Always Active
These cookies are necessary for the website to function and are sometimes referred to as “strictly necessary” cookies. They make sure the website delivers you information and services in an optimal way.
They are often set in response to an action you take, such as changing your cookie preferences, setting your privacy preferences, logging in to our website, asking the site to remember you on subsequent pages, or filling in forms. These cookies do not identify you personally.
You can set your browser to block or alert you about all cookies, including essential website cookies, but some parts of the site will not work as a result.
Cookies Details‎
Performance and Functionality Cookies
Performance and Functionality Cookies
These cookies enhance the performance and functionality of our websites and the services we provide. For example, these cookies can keep track of your visitor session in between visits, enable you to share content through social media, use embedded media players, and use comment features. They also help us balance website load and improve site speed and performance.
All information these cookies collect is aggregated and therefore anonymous. These cookies may be set by us or by third party providers whose services we have added to our websites. These cookies are non-essential, but without these cookies, certain functionality or enhanced features may become unavailable.
Cookies Details‎
Personalization and Analytics Cookies
Personalization and Analytics Cookies
These cookies collect information that is used to help us understand how our websites and content are used, help us customize our websites and application for you in order to enhance your experience, and help us improve the content that ASCO creates to better meet our members’ and visitors’ needs. Examples include cookies that show us which content might be most popular with our visitors, understand browsing history of our users, understand the effectiveness of our own advertising, and enable us to recommend content to individual users based on their profile and activities on the website.
These cookies may be set by us or by third party providers whose services we have added to our websites.
These cookies are non-essential to the functionality of the site and may contain information that enables us or our third party providers to identify you and build a profile of your interests. Without these cookies, you will not be able to have a customized or personalized experience within our website.
Cookies Details‎
Advertising Cookies and Social Media Cookies
Advertising Cookies and Social Media Cookies
Advertising (or Targeting) cookies are third party cookies that may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant ads on other sites.
Social Media Cookies are cookies set by a range of social media services that we have added to the site to enable you to share our content with your friends and networks. They are capable of tracking your activities across other sites and building a profile of your interests. This may impact the content and messages you see on other websites you visit.
These cookies and the data collected by the third parties may be combined with data from other users or data about your activity on other sites. While the data collected on our site is aggregate or non-personal, the data may be used by such third parties to link you on other platforms or otherwise identify you.
If you do not allow these cookies, you may experience less targeted advertising.
Cookies Details‎
Back Button
Cookie List
Search Icon
Filter Icon
Clear
checkbox labellabel
ApplyCancel
ConsentLeg.Interest
checkbox labellabel
checkbox labellabel
checkbox labellabel
View Cookies
Name
cookie name
Save Settings
iframeiframeBrand%3B24.0.0.0&uamb=0&uam=&uap=Linux%20x86_64&uapv=6.6.72&uaw=0&fledge=1&data=event%3Dgtag.config)
Download