XBiotech Announces Positive Phase II Final Efficacy Results from Investigator-Sponsored TASKIN Trial in Refractory Metastatic Colorectal Cancer

An exploratory analysis in 37 patients with right-sided tumors found a 62% reduction in death risk versus control through 12 months.

Rhea-AI Summary

XBiotech (XBIT) announced final Phase II TASKIN results meeting the trial’s prespecified primary efficacy success criterion in refractory metastatic colorectal cancer. The randomized study tested vilamakitug added to trifluridine/tipiracil, with or without bevacizumab. At 12 months, 49 of 80 evaluable experimental-arm patients (61.3%) were alive, exceeding the required 42 survivors; control survival was 44 of 79 (55.7%).

The 12-month rate of remaining on a viable treatment strategy was 31.2% versus 20.3% (p = 0.17). Median time without disease progression was 5.9 versus 5.6 months (p = 0.42). A prospective exploratory analysis of 37 patients with right-sided tumors found a 62% lower risk of death versus control through 12 months. Mean trifluridine/tipiracil compliance was 96.4%; permanent discontinuation of vilamakitug/placebo was 1.3%. XBiotech said the findings guide its advance toward registrational clinical development.

6 points · 1 major

PositiveiHow this balance works

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Rhea-AI gives every point it takes from this document a weight. Minor counts 1, Moderate 3 and Major 9, so one Major point outweighs several Minor ones. The bar adds up the weights on each side, and when neither side holds more than 65% of the total the balance reads Mixed.

It reads the document as published, with the same rules for every company, and it does not look at what the market expected or at how the stock traded, so a point can be objectively good on a day the stock falls.

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0 major · 2 points

Hollow bars mark forward-looking points. How the balance works

Positive

• Major pointPrimary efficacy criterion met: 49 survivors exceeded the prespecified threshold of 42 at 12 months.
• Moderate point. Forward-looking: it has not happened yet and may not happen.Registrational clinical development: XBiotech said the findings provide direction as it advances vilamakitug toward this stage.
• Minor point12-month survival was 61.3% (49/80) with vilamakitug versus 55.7% (44/79) with control.
• Minor pointExploratory right-sided tumor analysis (n = 37) found 62% lower death risk versus control through 12 months (p = 0.047).
• Minor pointExploratory right-sided tumor analysis found 61% lower treatment-strategy failure risk versus control through 12 months (p = 0.017).
• Minor pointMean trifluridine/tipiracil compliance was 96.4%; permanent vilamakitug/placebo discontinuation was 1.3%.

Negative

• Moderate pointOverall treatment-strategy comparison was not statistically significant: 12-month rates were 31.2% versus 20.3% (p = 0.17).
• Moderate pointProgression-free survival comparison was not statistically significant: median 5.9 versus 5.6 months; 12-month rates 25.0% versus 21.0% (p = 0.42).

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Details

Market move: XBIT -8.73% vs previous close. Phase II clinical data

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On Oct 19, the day this news came out, the latest delayed price for XBIT is 8.73% below the previous close. Our momentum scanner has recorded 16 alerts for this stock so far that day. The latest delayed price is $1.94. Relative volume is exceptionally heavy at 18.9x the average.

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Key Figures

12-month overall survival: 61.3% (49 of 80 evaluable patients) Efficacy threshold: 42 or more surviving patients Control-arm 12-month overall survival: 55.7% (44 of 79 evaluable patients) +5 more

12-month overall survival

61.3% (49 of 80 evaluable patients)

Vilamakitug arm; primary efficacy success criterion met

Efficacy threshold

42 or more surviving patients

Protocol-defined 12-month threshold

Control-arm 12-month overall survival

55.7% (44 of 79 evaluable patients)

Placebo plus standard chemotherapy

Right-sided tumor overall survival

62% risk reduction; HR=0.38; 95% CI: 0.14–0.99; Cox p=0.047; log-rank p=0.038

Exploratory subgroup through 12 months

Right-sided tumor time to strategy failure

61% risk reduction; HR=0.39; 95% CI: 0.18–0.85; Cox p=0.017; log-rank p=0.014

Exploratory subgroup through 12 months

Median progression-free survival

5.9 months vs 5.6 months; log-rank p=0.42

Vilamakitug arm vs control arm

Chemotherapy mean compliance

96.4%

Trifluridine/tipiracil treatment adherence

Permanent discontinuation rate

1.3%

Vilamakitug/placebo

Key Terms

overall survival, monoclonal antibody, simon two-stage design, progression-free survival, +1 more

5 terms

overall survival medical

"with 61.3% 12-month overall survival."

Overall survival is the average or median length of time patients remain alive after starting a treatment or entering a clinical study, measured regardless of cause of death. Investors care because it is a clear, hard measure of a therapy’s real-world benefit — like timing how long a new battery actually runs — and strong improvements in overall survival can drive regulatory approval, market adoption and revenue potential.

monoclonal antibody medical

"XBiotech’s anti-IL-1α monoclonal antibody"

A monoclonal antibody is a laboratory-made protein designed to recognize and attach to a specific target in the body, such as a disease-causing substance or cell. It functions like a highly precise lock-and-key tool, helping to treat or detect illnesses. For investors, companies developing monoclonal antibodies can represent promising opportunities in the healthcare sector, especially as these treatments often address unmet medical needs.

simon two-stage design technical

"under a Simon two-stage design."

A Simon two-stage design is a clinical trial plan used early in drug development to test whether a treatment shows enough promise to continue. It works like a two-step audition: a small first group is tested and if results are poor the trial stops early to save time and money, while acceptable early results trigger a second, larger group; investors care because it limits wasted capital and reduces risk by quickly filtering out ineffective therapies.

progression-free survival medical

"Progression-Free Survival (PFS): Median PFS was"

Progression-free survival is the length of time during and after a treatment that a patient's disease does not get worse, measured from the start of treatment until the disease shows measurable signs of progression or the patient dies. Investors care because longer progression-free survival in clinical trials often signals that a drug is effective, improving chances of regulatory approval, market adoption, and revenue potential—think of it as a stopwatch showing how long a therapy can keep the illness at bay.

hazard ratio medical

"Hazard Ratio [HR] = 0.38; 95% CI: 0.14–0.99"

A hazard ratio is a way scientists compare the chance of something happening over time between two groups, like patients taking different medicines. If the ratio is high, it means one group is more likely to experience the event sooner or more often, which helps determine how effective a treatment is or how risky a situation might be.

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Investigator-sponsored study funded by the French National Cancer Institute (INCa) meets pre-specified primary efficacy success criterion with 61.3% 12-month overall survival.

Exploratory Subgroup analysis reveals significant survival benefit in right-sided tumors.

AUSTIN, Texas, Oct. 19, 2026 (GLOBE NEWSWIRE) -- XBiotech Inc. (NASDAQ: XBIT) today announced positive final efficacy results from the randomized Phase II portion of the multicenter TASKIN clinical trial. The investigator-sponsored study—funded by the French National Cancer Institute (INCa) and coordinated by investigators at the Centre Georges-François Leclerc (CGFL) in Dijon, France—evaluated the addition of XBiotech’s anti-IL-1α monoclonal antibody, XB2001 (Natrunix™, vilamakitug), to standard-of-care trifluridine/tipiracil (TAS-102) with or without bevacizumab in patients with refractory metastatic colorectal cancer (mCRC).

The TASKIN Phase II study met its pre-specified primary efficacy success criterion under a Simon two-stage design. At the 12-month landmark analysis, 49 of 80 evaluable patients (61.3%) in the vilamakitug experimental arm were alive, surpassing the protocol-defined threshold of 42 or more surviving patients required to establish efficacy. In the control arm (placebo plus standard chemotherapy), 44 of 79 evaluable patients (55.7%) were alive at 12 months.

Professor François Ghiringhelli, M.D., Ph.D., Principal Investigator of the TASKIN study and Director of the Oncology Department at Centre Georges-François Leclerc, commented:

"Patients with refractory metastatic colorectal cancer face severe therapeutic limitations and poor survival outcomes. Meeting our pre-specified primary milestone provides compelling evidence that targeting IL-1α plays a meaningful role in tumor biology. Most striking is the magnitude of benefit observed in right-sided colorectal cancers, which has been a historically aggressive disease subset with high unmet medical need. The alignment between this pronounced clinical survival advantage and elevated basal IL-1α tumor expression offers a clear biological rationale for this therapy."

Summary of Overall Findings

• Time to Strategy Failure (TSF): The 12-month TSF rate, which captured the duration for which the overall treatment strategy remains viable, was 31.2% in the vilamakitug arm compared to 20.3% in the control arm (log-rank p = 0.17).
• Progression-Free Survival (PFS): Median PFS was 5.9 months for the vilamakitug arm versus 5.6 months for the control arm, with a 12-month PFS rate of 25.0% versus 21.0% (log-rank p = 0.42), with survival curves visibly separating after month 7.
• Safety & Treatment Adherence: Vilamakitug demonstrated high feasibility in combination with chemotherapy, showing a 96.4% mean compliance rate for trifluridine/tipiracil and only a 1.3% permanent discontinuation rate for vilamakitug/placebo
  

Exploratory Endpoint Analysis, Efficacy in Right-Sided Primary Tumors

A prospective exploratory analysis identified a statistically significant benefit in patients with right-sided (proximal) primary tumors (n = 37), a subtype characterized by aggressive tumor biology, high unmet medical need, and poor outcomes under standard therapies:

• Overall Survival (OS): Vilamakitug demonstrated a statistically significant 62% reduction in the risk of death compared to control (Hazard Ratio [HR] = 0.38; 95% CI: 0.14–0.99; Cox p = 0.047, log-rank p = 0.038) through 12 months.
• Time to Strategy Failure (TSF): Vilamakitug achieved a 61% reduction in the risk of treatment strategy failure compared to control (HR = 0.39; 95% CI: 0.18–0.85; Cox p = 0.017, log-rank p = 0.014) through 12 months.

Sushma Shivaswamy, Ph.D., Chief Scientific Officer and Interim Chief Executive Officer of XBiotech, stated:

"We are deeply grateful to Professor Ghiringhelli, the team at Centre Georges-François Leclerc, the French National Cancer Institute, and all the participating patients for advancing this important trial. By uncovering a biomarker-anchored patient population in right-sided disease that derives substantial clinical benefit from vilamakitug, TASKIN provides a focused and validated direction as we advance vilamakitug toward registrational clinical development."

About the TASKIN Trial The TASKIN study (NCT05201352) is an investigator-sponsored clinical trial funded by the French National Cancer Institute (INCa) and sponsored by the Centre Georges-François Leclerc (CGFL) in Dijon, conducted across clinical cancer centers in France. The Phase I portion determined the safety and recommended Phase II dose of vilamakitug with trifluridine/tipiracil and bevacizumab. The double-blind Phase II portion enrolled heavily pre-treated refractory mCRC patients randomized 1:1 to receive standard-of-care trifluridine/tipiracil (± bevacizumab) in combination with either vilamakitug or placebo until disease progression or unacceptable toxicity.

About vilamakitug (Natrunix™, XB2001) A True Human™ therapeutic monoclonal antibody developed solely by XBiotech. Vilamakitug is derived from a human donor that had a natural human immune response against interleukin1alpha (IL-1a). IL-1α is an apex mediator that creates the environment to support growth and emergence of malignant cells. IL-1a stimulates angiogenesis, cellular dysregulation, tissue matrix remodeling, tumor migration, adhesion, and invasion, hallmark physiological features of cancer. Remarkably, vilamakitug has been shown clinically to simultaneously reduce levels of each of VEGF-A, ErbB2/HER2, PDGF, and EGF in cancer patients. Rather than a simple cytotoxic agent that kills all growing tissue, vilamakitug therefore can target multiple aspects of the malignant disease process, facilitating anti-tumor effects while controlling the disease process and reducing disease morbidity. Dramatic reduction in incidence of cancer-related morbidity, reduced hospitalization, reduced duration of hospitalization, reduced symptoms such as diarrhea, fatigue and pain, reduced tumor burden, and longer progression free survival and overall survival have been observed in another study in advanced cancer.

About XBiotech XBiotech is a fully integrated global biosciences company dedicated to pioneering the discovery, development and commercialization of therapeutic antibodies based on its True Human™ discovery platform. XBiotech currently is advancing antibody therapies to redefine the standards of care in oncology, inflammatory conditions and infectious diseases. Headquartered in Austin, Texas, XBiotech also is leading the development of innovative biotech manufacturing technologies designed to more rapidly, cost-effectively and flexibly produce new therapies urgently needed by patients worldwide. For more information, visit www.xbiotech.com.

Cautionary Note on Forward-Looking Statements This press release contains forward-looking statements, including declarations regarding management's beliefs and expectations that involve substantial risks and uncertainties. In some cases, you can identify forward-looking statements by terminology such as "may," "will," "should," "would," "could," "expects," "plans," "contemplate," "anticipates," "believes," "estimates," "predicts," "projects," "intend" or "continue" or the negative of such terms or other comparable terminology, although not all forward-looking statements contain these identifying words. Forward-looking statements are subject to inherent risks and uncertainties in predicting future results and conditions that could cause the actual results to differ materially from those projected in these forward-looking statements. These risks and uncertainties are subject to the disclosures set forth in the "Risk Factors" section of certain of our SEC filings. Forward-looking statements are not guarantees of future performance, and our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate, may differ materially from the forward-looking statements contained in this press release. Any forward-looking statements that we make in this press release speak only as of the date of this press release. We assume no obligation to update our forward-looking statements whether as a result of new information, future events or otherwise, after the date of this press release.

Contact:

Wenyi Wei
publicrelations@xbiotech.com
tel. 737-207-4600

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

Did XBiotech’s TASKIN Phase II trial meet its primary efficacy criterion?

Yes. At 12 months, 49 of 80 evaluable patients receiving vilamakitug were alive, exceeding the prespecified requirement of at least 42 survivors. This met the trial’s success criterion under its Simon two-stage design; control-arm survival was 44 of 79 evaluable patients.

What did XBiotech’s TASKIN trial show in right-sided colorectal tumors?

The prospective exploratory analysis of 37 patients found a 62% reduction in death risk and a 61% reduction in treatment-strategy failure risk versus control through 12 months. The death-risk hazard ratio was 0.38 (95% confidence interval: 0.14–0.99); the treatment-strategy failure hazard ratio was 0.39 (0.18–0.85).

Who funded and coordinated XBiotech’s TASKIN trial?

The investigator-sponsored TASKIN study was funded by the French National Cancer Institute (INCa) and coordinated by investigators at Centre Georges-François Leclerc in Dijon, France.