On April 17, 2026 Volastra Therapeutics, a clinical-stage oncology company pioneering therapies targeting chromosomal instability (CIN), reported multiple scientific disclosures coinciding with the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2026, taking place April 17–22 in San Diego, California. The data define an Rb pathway–driven pan-cancer development framework for KIF18A inhibitors and highlight a proprietary p16 IHC biomarker approach designed to translate that strategy clinically, reinforcing Volastra’s leadership in advancing CIN biology into therapeutic opportunity.

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Separate from its AACR (Free AACR Whitepaper) 2026 presentation, Volastra has posted "KIF18A Inhibition as a Therapeutic Strategy in Cancers with Rb Pathway Inactivation" (Andreu et al. DOI: View Source – preprint publication). Drawing on what is believed to be one of the largest datasets of its kind, the work identifies Rb pathway inactivation as the mechanistic basis of response to KIF18A inhibition and establishes a development path that extends well beyond high-grade serous ovarian cancer.

The study includes clinical data from a substantial cohort of 79 heavily pretreated patients with high-grade serous ovarian cancer treated with either of two distinct KIF18A inhibitors, sovilnesib and VLS-1488. The concordance of the biomarker-defined signal across both agents is particularly compelling and argues against a drug-specific observation. Biomarker-positive tumors were distinguished by marked enrichment for objective responses, durable disease control, and longer progression-free survival, yielding a sharp clinical separation from biomarker-negative disease and strongly supporting both the biomarker strategy and prospective clinical development.

These findings reposition KIF18A inhibition from a histology-defined opportunity into a pan-cancer synthetic lethal strategy centered on one of the most commonly disrupted tumor suppressor pathways in human cancer. This creates a credible path across what is estimated to represent approximately 15% of human cancers. Within that biology, Volastra has identified a proprietary p16 IHC biomarker strategy that enriches for response to its KIF18A inhibitors and provides a practical route to clinical translation.

"The data provide a strong scientific rationale for using p16 status to identify patients most likely to benefit from KIF18A inhibition," said David Southwell, Chief Executive Officer of Volastra Therapeutics. "Importantly, this work reframes KIF18A inhibition from a narrow single cancer-type opportunity into a broader pan-cancer strategy grounded in Rb pathway biology. This p16 biomarker approach provides a practical way to translate that insight into clinical development and patient selection."

AACR Poster Highlights Clear Synergy with Taxanes and Other Microtubule-Targeting Agents

Volastra will also present an official AACR (Free AACR Whitepaper) poster titled "Combination of VLS-1488 and taxanes induces anti-tumor synergistic effect in cancer cells" in the Experimental and Molecular Therapeutics, Novel Antitumor Agents 1 Session on April 19 from 2-5PM Pacific Time (PT) (Poster section 17, poster 18). The presentation will highlight preclinical combination data showing clear synergistic activity between KIF18A inhibition and taxanes and other microtubule-targeting agents. These findings support a development strategy that could extend KIF18A inhibitors into earlier lines of therapy, including combination approaches in frontline settings.

"The totality of these data help define both the monotherapy and combination development paths for KIF18A inhibitors," said Samuel F. Bakhoum, M.D., Ph.D., Co-Founder and Chief Scientific Officer of Volastra Therapeutics. "With this new mechanistic understanding of KIF18A inhibitor sensitivity, it is evident that the biomarker data will help us identify patients most likely to benefit from monotherapy, while the combination findings point to a precision-based approach to identify the most rational therapeutic partners for development in earlier line settings."

Separately, Dr. Bakhoum, also an adjunct faculty member at the Geisel School of Medicine at Dartmouth, will chair an AACR (Free AACR Whitepaper) educational session "Chromosomal Instability in Cancer: From Mechanism to Therapy and Clinical Translation" on Saturday, April 18, 2026, in his academic capacity. The session reflects the field’s growing appreciation of CIN as both a driver of aggressive disease and a source of therapeutic vulnerability.

"This momentum underscores the growing recognition of CIN biology and the increasing importance of CIN-directed therapeutic strategies across oncology," Dr. Bakhoum said.

(Press release, Volastra Therapeutics, APR 17, 2026, View Source [SID1234664476])