Verastem Oncology Announces Encouraging Preliminary Data from Ongoing Phase 1/2a Dose Escalation Trial of VS-7375, an Oral KRAS G12D (ON/OFF) Inhibitor, in Patients with KRAS G12D Mutant Solid Tumors First two monotherap

Verastem Oncology Announces Encouraging Preliminary Data from Ongoing Phase 1/2a Dose Escalation Trial of VS-7375, an Oral KRAS G12D

(ON/OFF) Inhibitor, in Patients with KRAS G12D Mutant Solid Tumors

First two monotherapy

dose levels (400 mg QD and 600 mg QD) cleared, with no dose-limiting toxicities reported

Promising anti-tumor

activity observed in patients with various solid tumors, including advanced pancreatic ductal adenocarcinoma

No nausea, vomiting,

or diarrhea greater than Grade 1 was observed

Enrollment initiated

for VS-7375 in combination with cetuximab in patients with advanced KRAS G12D mutant solid tumors, including colorectal cancer

an interim safety and efficacy update on the Phase 1/2a trial in the first half of 2026

WIRE)-Oct. 23, 2025-- Verastem Oncology (Nasdaq: VSTM), a biopharmaceutical company committed to advancing new medicines for patients

with RAS/MAPK-pathway-driven cancers, today announced encouraging preliminary data from the first two dose levels in its ongoing Phase

1/2a clinical trial evaluating VS-7375, a potential best-in-class oral KRAS G12D (ON/OFF) inhibitor, in patients with previously-treated

advanced KRAS G12D mutant solid tumors. In addition, while monotherapy dose escalation continues, the Company announced it has initiated

patient enrollment for the first dose escalation combination cohort evaluating VS-7375 with cetuximab.

"Preliminary safety and tolerability

data from our ongoing Phase 1/2a trial indicate that VS-7375, a potential best-in-class oral KRAS G12D (ON/OFF) inhibitor, can be administered

at efficacious doses while effectively managing gastrointestinal side effects," said Dan Paterson, president and chief executive

officer of Verastem Oncology. "While still early, we are pleased to see anti-tumor activity among pre-treated patients with advanced

pancreatic cancer and other solid tumors. As we continue monotherapy dose escalation, we are excited to open the combination cohort evaluating

VS-7375 with cetuximab just months after trial initiation. By starting this combination cohort at a dose of VS-7375 that has previously

demonstrated monotherapy efficacy, we expect to accelerate our clinical development program with other standard-of-care combination cohorts."

VS-7375-101 is a Phase 1/2a study being

conducted in the U.S., with plans underway to expand globally, and is evaluating the safety and efficacy of VS-7375 in patients with

previously-treated advanced KRAS G12D mutant solid tumors, including advanced pancreatic ductal adenocarcinoma (PDAC), both as monotherapy

and in combination with other standard of care treatments.

In the study, VS-7375 cleared both the

400 mg daily (QD) and 600 mg QD monotherapy doses with no dose-limiting toxicities (DLTs) observed. In addition, no new safety signals

have been observed relative to earlier data presentations in both PDAC and non-small cell lung cancer (NSCLC) by our partner, GenFleet

Therapeutics, in its ongoing Phase 1 /2 clinical study in China evaluating VS-7375 (known as GFH375). Specifically, at the two dose levels

evaluated in the U.S. cohorts, no nausea, vomiting, or diarrhea greater than Grade 1 were reported. Monotherapy dose escalation in the

VS-7375-101 study started at the efficacious doses identified in GenFleet's study, 400 mg QD and 600 mg QD. GenFleet chose 600

mg QD as their recommended Phase 2 dose (RP2D) in China.

Of the five efficacy evaluable patients

in the VS-7375-101 study with at least one scan, four out of five patients have had a tumor reduction and are still on treatment. The

remaining patients receiving either the 400 mg QD or 600 mg QD doses have not yet reached their first response assessment. The study's

dose escalation continues with evaluating 900 mg QD monotherapy and the combination cohort evaluating VS-7375 with cetuximab is now open

and enrolling patients. The cohort will enroll patients with advanced solid tumors, including colorectal cancer.

"We're encouraged by the

early safety experience in this study, including the GI tolerability we've seen to date and absence of cutaneous toxicities, along

with the early signs of anti-tumor activity. These preliminary findings are promising, and we look forward to the continued evaluation

of VS-7375 both as monotherapy and now in combination with cetuximab as there remains a significant unmet need for treatments specifically

targeting KRAS G12D-mutant cancers," said John Hayslip, M.D., chief medical officer of Verastem Oncology.

Subject to the results of the Phase

1 dose escalation combination of VS-7375 and cetuximab, Verastem plans to initiate a combination expansion cohort in colorectal cancer.

Following the ongoing monotherapy dose escalation to 900 mg QD, the Company expects to select the recommended Phase 2 dose and advance

subsequent efficacy and safety analysis of monotherapy VS-7375 in patient expansion cohorts with advanced PDAC and NSCLC. The Company

plans to report an interim safety and efficacy update on the Phase 1/2a trial of VS-7375 in the first half of 2026.

KRAS G12D represents 26% of all KRAS

mutations, making it the most prevalent KRAS mutation in human cancers. The KRAS G12D mutation occurs most commonly in pancreatic (37%),

colorectal (12.5%), endometrial (8%), and non-small cell lung (5%) cancers. Currently, no therapies are approved by the U.S. Food

and Drug Administration (FDA) specifically targeting KRAS G12D mutations in cancer.

About VS-7375, an Oral KRAS G12D

VS-7375 is a potential best-in-class,

potent, and selective oral KRAS G12D (ON/OFF) inhibitor. VS-7375 is the lead program from the Verastem Oncology discovery and development

collaboration with GenFleet Therapeutics. Verastem announced in April 2025 that the U.S. Investigational New Drug (IND) application for

VS-7375 was cleared and initiated a Phase 1/2a clinical trial in June 2025. GenFleet's IND for VS-7375 (known as GFH375 in China)

was approved in China in June 2024, and the first patient was dosed in a Phase 1/2 study in July 2024. Verastem selected VS-7375

as its lead program in December 2023 and the license for VS-7375 that was exercised in January 2025 is the first one from this collaboration.

This license gives Verastem development and commercialization rights outside the GenFleet markets of mainland China, Hong Kong, Macau,

Phase 1/2a Study of VS-7375

is a Phase 1/2a clinical trial being conducted in the U.S., with the potential to expand globally, and will evaluate the safety and efficacy

of VS-7375 in patients with advanced KRAS G12D mutant solid tumors. The starting dose for the Phase 1 study of 400 mg is based on the

dose identified in the initial data from the GenFleet study to accelerate the trial's progress. Verastem plans to dose escalate

across levels where responses were observed in GenFleet's study and will assess in the Phase 2a portion the efficacy and safety

of VS-7375, both as monotherapy and in combination, in patients with advanced solid tumors, such as pancreatic, colorectal, and non-small

Verastem Oncology (Nasdaq: VSTM) is

a biopharmaceutical company committed to developing and commercializing new medicines to improve the lives of patients diagnosed with

RAS/MAPK pathway-driven cancers. Verastem markets AVMAPKI FAKZYNJA CO-PACK in the U.S. Our pipeline

is focused on novel small molecule drugs that inhibit critical signaling pathways in cancer that promote cancer cell survival and tumor

growth, including RAF/MEK inhibition, FAK inhibition, and KRAS G12D inhibition. For more information, please visit www.verastem.com and

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