On April 17, 2023 MapKure, LLC, BeiGene, Ltd. (NASDAQ: BGNE; HKEX: 06160; SSE: 688235), and SpringWorks Therapeutics, Inc. (NASDAQ: SWTX), reported that they will present updated clinical data from the Phase 1a/1b study of BGB-3245, an investigational, selective RAF dimer inhibitor, in adult patients with advanced or refractory solid tumors harboring MAPK pathway aberrations (Press release, BeiGene, APR 17, 2023, View Source [SID1234630141]). The data are being presented today in an oral presentation at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2023, taking place in Orlando, Florida.

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This press release features multimedia. View the full release here: View Source

"The promising data we are sharing at AACR (Free AACR Whitepaper) demonstrate the value of our next-generation RAF dimer inhibitor, BGB-3245, as a monotherapy in patients with MAPK pathway-altered cancers, especially its potential to address key primary and resistance gene alterations that are currently unaddressed by approved therapies," said Lusong Luo, Ph.D., Acting CEO of MapKure and Senior Vice President, External Innovation at BeiGene. "We believe that our early clinical data supported the advancement into our selected expansion cohorts which are now underway."

"SpringWorks is committed to developing genomically-targeted therapies for patients with cancer and our MAPK directed portfolio is a cornerstone of our efforts. In particular, we are encouraged by the promising activity BGB-3245 is showing in patients with MAPK pathway aberrations," said Saqib Islam, CEO of SpringWorks. "We and our partners are excited by the advancement of this program and are eager to continue making strides to benefit patients in significant need of new therapeutic options."

Oral Presentation at the 2023 AACR (Free AACR Whitepaper) Annual Meeting:

A first-in-human, phase 1a/1b, open-label, dose-escalation and expansion study to investigate the safety, pharmacokinetics, and antitumor activity of the RAF dimer inhibitor BGB-3245 in patients with advanced or refractory tumors

Presenter: Alison M. Schram, M.D., Memorial Sloan Kettering Cancer Center in New York
Session Title: Mini-symposium Session CTMS02 – Targeting the KRAS Pathway in the Clinic
Abstract #: CT031
Session Date and Time: Monday, April 17, 2023, from 3:20-3:30 PM ET

This ongoing Phase 1a/1b trial (NCT04249843) is an open-label, dose escalation and expansion study of BGB-3245 in adult patients with advanced or refractory solid tumors harboring MAPK pathway alterations. Results from the Phase 1a dose-escalation and dose-finding study are being presented at AACR (Free AACR Whitepaper). This portion of the study was designed to evaluate the safety, pharmacokinetics, preliminary antitumor activity of BGB-3245, and to determine its maximum tolerated dose and/or recommended Phase 2 dose to be used in select expansion cohorts.

As of the data cut-off of September 1, 2022, 42 patients were treated across six dose levels (5-60 mg daily). Patients were heavily pre-treated, having received a median three prior lines of therapy (range 1-9), including standard of care immunotherapy and targeted therapy regimens. Results demonstrated that BGB-3245 had a manageable safety profile, with adverse event findings consistent with other MAPK pathway inhibitors. The most common treatment-related adverse events (>15%) were rash acneiform (33%), rash maculopapular (24%), and fever (17%). The 40 mg once daily dose was determined to be the maximum tolerated dose of BGB-3245. In addition, encouraging anti-tumor activity was observed in heavily pretreated patients, with an objective response rate of 18% (6 confirmed responses including one complete response in 33 efficacy evaluable patients). The disease control rate was 79% and clinical benefit rate was 42%. Objective responders include patients with tumors harboring BRAF V600E that had progressed on prior BRAF/MEK inhibitors with or without checkpoint inhibitor treatment, BRAF Class II mutation, BRAF fusion, NRAS and KRAS mutations. Median time on treatment was approximately 5 months (range: 1.9-23.6 months) and 9 patients remain on treatment. These data supported the advancement of BGB-3245 into the Phase 1b dose expansion portion of the study, which has been enrolling patients since October 2022 in defined cohorts.

"These data support the ongoing investigation of BGB-3245 in defined cohorts, including BRAF V600 tumors that have progressed after prior BRAF and/or MEK inhibitor treatment, solid tumors with BRAF class II mutations and BRAF fusions, and NRAS mutant melanoma," said Alison M. Schram, M.D., Assistant Attending Physician at Memorial Sloan Kettering Cancer Center in New York. "These patients have very limited treatment options and I look forward to the further development of BGB-3245 as it continues to advance through the dose expansion cohorts."

About BGB-3245

BGB-3245 is an investigational, oral, selective small molecule inhibitor of RAF monomer and dimer forms. Preclinical data demonstrate that BGB-3245 has activity in tumor models that have BRAF/MEK inhibitor-resistance mutations, suggesting BGB-3245 could provide a therapeutic option for patients who have progressed on prior BRAF and/or MEK inhibitions. In addition, BGB-3245 has shown activity in preclinical models that have BRAF class II/III mutations, fusions, and splice isoforms, for which approved BRAF inhibitors are ineffective. These mutations and fusions have been identified in several solid tumors to be drivers of cancer growth, including in melanoma, non-small cell lung cancer, colorectal cancer, thyroid cancer, and other cancers.

In addition to its development as a monotherapy in several genetically defined solid tumor types, a Phase 1/2a combination study of BGB-3245 and mirdametinib is ongoing (NCT05580770) and BGB-3245 also has the potential to be used in rational combination therapies in the future.