Akamis Bio, a privately held clinical-stage oncology company based in Cambridge, Massachusetts, announced on October 14, 2026, that it has completed enrollment in FORTRESS, its Phase 1b study evaluating the investigational oncolytic immunotherapy NG-350A in combination with chemoradiotherapy for mismatch repair-proficient locally advanced rectal cancer. The study enrolled 33 patients across seven clinical centers in the United States and United Kingdom, bringing recruitment to a close ahead of an anticipated topline results announcement during the first half of 2027.
The completion follows encouraging preliminary findings disclosed in April 2026, when five of the first ten patients completing the 12-week active treatment period achieved a clinical complete response or near-complete response. The resulting 50% composite response rate compared favorably with the approximately 25% historical benchmark that Akamis identifies for chemoradiotherapy alone at the same assessment point. However, the investigation is single-arm and open-label, so the numerical difference cannot establish a treatment advantage over a concurrently randomized control group.
NG-350A is an intravenously administered, tumor-selective oncolytic immunotherapy designed to deliver a CD40 agonist antibody into the tumor environment. Its engineered viral platform is intended to infect and replicate preferentially within malignant tissue, allowing expression of an immune-stimulating molecule close to the cancer cells. Akamis is investigating whether this approach can enhance responses to conventional chemoradiotherapy in tumors that are generally less sensitive to immune checkpoint inhibitors.
The company expects to use the completed FORTRESS dataset to guide discussions with regulators about a randomized Phase 2 trial planned for the second half of 2027. That study would provide an opportunity to compare NG-350A plus chemoradiotherapy directly with an appropriate standard treatment regimen. The next development decision will depend on whether the initial response signal is sustained across all enrolled patients and accompanied by an acceptable safety profile.
Why is Akamis targeting mismatch repair-proficient locally advanced rectal cancer?
Locally advanced rectal cancer generally refers to disease extending beyond the innermost layers of the rectum or involving regional lymph nodes without necessarily spreading widely to distant organs. Treatment often requires a combination of chemotherapy, radiation and surgery, depending on disease stage, clinical risk and response. These interventions can control cancer but may also create substantial long-term effects on bowel, urinary and sexual function.
An important biological distinction concerns DNA mismatch repair. Tumors that are mismatch repair-deficient, known as dMMR, accumulate numerous genetic changes and may be particularly sensitive to immune checkpoint inhibition. Those with proficient mismatch repair, or pMMR, generally have different immune characteristics and are less likely to produce the exceptionally strong responses observed with checkpoint inhibitor monotherapy in selected dMMR rectal cancers.
The distinction has become more clinically important following research with the PD-1 inhibitor dostarlimab. A 2025 study published in the New England Journal of Medicine reported clinical complete responses among all 49 dMMR rectal cancer patients who completed the investigated course of treatment. Those results highlighted the potential for carefully selected patients to avoid conventional chemoradiotherapy and surgery under specialist surveillance.
However, the dostarlimab findings cannot be extrapolated to the much larger pMMR population. Differences in tumor mutation characteristics and immune recognition affect how cancers respond to immunotherapy. Akamis is attempting to address that problem through an oncolytic approach designed to stimulate antitumor immune activity within pMMR tumors.
The company’s objective is not simply to repeat an existing checkpoint inhibitor strategy. It is investigating whether local immune activation can strengthen the effects of chemoradiotherapy and increase the proportion of patients achieving substantial tumor regression. That benefit must be demonstrated independently in the intended pMMR population.
How does NG-350A use an oncolytic virus to activate CD40 signaling?
NG-350A is based on Akamis Bio’s T-SIGn platform, which uses engineered adenoviruses designed to selectively replicate within tumor tissue. The viral construct carries genetic instructions for a CD40 agonist monoclonal antibody, allowing the therapeutic protein to be produced locally after the virus reaches suitable malignant cells. This differs from administering a conventional systemic antibody without an associated tumor-directed delivery mechanism.
CD40 is an immune receptor expressed by several antigen-presenting cells, including dendritic cells and certain macrophages. Stimulating the pathway can influence how these cells process and present tumor-associated material to T cells. The intended result is stronger immune recognition of malignant tissue and potentially more effective antitumor activity.
The local expression strategy aims to concentrate immune stimulation within the tumor environment while reducing unwanted activity elsewhere in the body. Systemically administered immune agonists can encounter limitations involving inflammatory toxicity and the difficulty of achieving sufficient drug activity at the tumor site. Producing an agonist within malignant tissue could theoretically improve the balance between activity and systemic exposure.
However, selective viral replication and local antibody expression are not absolute guarantees of tumor confinement. Viral distribution, host immune responses and differences between tumors can influence how the treatment behaves. The clinical programme must assess whether the proposed targeting characteristics translate into effective and tolerable treatment.
Akamis has previously studied NG-350A as monotherapy in the FORTITUDE programme and in combination with pembrolizumab in FORTIFY. The company reported evidence of tumor-selective delivery, viral replication and transgene expression across those investigations. These findings provide a mechanistic foundation for FORTRESS without establishing that the current combination improves patient outcomes.
What did the first ten FORTRESS patients reveal about treatment response?
In April 2026, Akamis disclosed preliminary findings involving the first ten participants who had completed the active treatment period. Five met the study’s definition of a clinical complete response or near-complete response at the 12-week assessment. The resulting composite response rate was 50%, with the company reporting no serious adverse events or new safety signals attributed to NG-350A in that initial analysis.
The numerical response result attracted attention because Akamis uses an expected composite response rate of approximately 25% for chemoradiotherapy alone at the corresponding 12-week assessment. The initial observation was therefore twice that benchmark on a simple percentage basis. However, the treatment and benchmark populations were not randomized against one another.
Historical comparisons can be influenced by differences in patient selection, disease staging, treatment delivery and response assessment. In a ten-patient cohort, each participant also represents ten percentage points of the reported outcome. A small change in the number of responses can therefore produce a substantial difference in the headline rate.
The complete 33-patient analysis will provide a more informative estimate. It will also make it possible to examine whether the initial response rate was representative of later participants or reflected favorable characteristics within the first cohort. Nevertheless, the final FORTRESS result will remain a single-arm estimate rather than a direct comparison with standard chemoradiotherapy.
The April safety observation is similarly preliminary. An absence of serious events attributed to NG-350A among ten patients provides encouraging information, but it cannot reliably characterize uncommon complications. The full study will need to report adverse events across the enrolled population, including their severity, attribution and relationship to the combination treatment.
How does the FORTRESS study evaluate complete and near-complete responses?
FORTRESS, registered as NCT06459869, is an open-label, single-arm, multicenter Phase 1b investigation. It enrolled adults with histologically confirmed locally advanced rectal adenocarcinoma, generally corresponding to clinical stage II or III based on pelvic magnetic resonance imaging. The protocol also includes specific eligibility characteristics relating to recurrence risk and selected patients with oligometastatic disease.
Participants receive NG-350A in combination with chemoradiotherapy during a 12-week active treatment period. The chemoradiotherapy regimen includes oral capecitabine and long-course intensity-modulated radiation therapy. This provides a conventional treatment backbone against which the investigational immunotherapy’s potential contribution can be explored.
The primary endpoint is a composite response measure combining clinical complete response and near-clinical complete response at 12 weeks. Clinical complete response generally indicates that available clinical assessments show no detectable residual tumor, while near-complete response describes substantial regression with findings that do not fully satisfy complete response criteria. These outcomes are related but should not be treated as equivalent.
A clinical complete response also differs from pathological complete response, which is determined through microscopic examination of tissue following surgical resection. Clinical evaluation relies on tools such as imaging, endoscopy and examination, and some residual disease may not be readily detectable. Near-complete responses introduce additional uncertainty because the tumor has not met full clinical disappearance criteria.
The composite endpoint may be useful for identifying biological activity at an early stage. However, it does not automatically establish that patients can safely avoid surgery or that they will remain free from cancer recurrence. Those outcomes require longer follow-up and careful assessment within an appropriate clinical pathway.
Why could increasing response rates matter for organ preservation?
Rectal cancer treatment can have substantial consequences for quality of life, particularly when patients require major surgery. Depending on the tumor’s location and the operation performed, treatment may affect bowel function, urinary control, sexual health and the need for temporary or permanent diversion of intestinal contents. Approaches that safely avoid unnecessary surgery are therefore an important area of research.
For selected patients achieving a confirmed clinical complete response after neoadjuvant treatment, specialized centers may consider nonoperative management with intensive surveillance. Often described as a watch-and-wait strategy, this approach requires careful monitoring because residual or recurrent disease can emerge after an apparently successful initial response. It is not appropriate for every patient.
If NG-350A increases the proportion of pMMR rectal cancer patients achieving durable complete responses, it could eventually contribute to organ-preservation strategies. However, an early composite endpoint including near-complete responses is not sufficient to establish that outcome. The clinical importance depends on whether responses become complete, remain durable and are associated with acceptable long-term cancer control.
The timing of assessment is another consideration. Tumor regression can continue after chemoradiotherapy, meaning response rates may depend on when investigators perform imaging and clinical evaluations. Comparisons across studies using different assessment schedules can therefore be misleading.
A future randomized study would provide stronger evidence about whether NG-350A improves the proportion of patients achieving clinically relevant responses. Longer-term outcomes such as disease-free survival, local recurrence and organ preservation would help establish whether early tumor regression translates into lasting benefit.
What will circulating tumor DNA and MRI assessments add to the FORTRESS results?
FORTRESS includes secondary endpoints intended to characterize more than the initial clinical response category. These include magnetic resonance tumor regression grade, or mrTRG, and the assessment of circulating tumor DNA clearance. Both measures may provide additional information about how the cancer responds to treatment.
MRI-based tumor regression assessment can help evaluate changes in the treated tumor and surrounding tissue. It may provide information about residual disease characteristics that are not fully captured by a simple classification of complete or near-complete clinical response. However, imaging findings must be interpreted alongside endoscopic and clinical observations.
Circulating tumor DNA testing looks for tumor-associated genetic material released into blood. A reduction or clearance of detectable ctDNA may indicate a change in disease burden and could provide information about residual disease risk. Nevertheless, test sensitivity and the timing of sample collection influence interpretation.
A negative ctDNA result does not establish that every malignant cell has been eliminated. Similarly, the absence of circulating tumor DNA cannot independently authorize omission of surgery or conventional surveillance. The clinical value of the measurement depends on validated assays and evidence connecting results with subsequent outcomes.
For NG-350A, combining clinical response, imaging and molecular findings could provide a more informative picture of treatment activity. Consistent improvements across these measures would strengthen the rationale for randomized testing, even though the Phase 1b study cannot establish comparative efficacy.
Why is the earlier CEDAR study relevant to Akamis’ development strategy?
The FORTRESS programme builds on earlier research involving EnAd, a first-generation oncolytic immunotherapy from Akamis’ technology platform. The company supported the CEDAR investigation, which evaluated an oncolytic treatment approach alongside chemoradiotherapy in locally advanced rectal cancer. That research provided initial experience combining viral therapy with an established radiation and chemotherapy regimen.
Akamis has stated that CEDAR showed an improvement in a composite tumor response measure relative to expected outcomes with chemoradiotherapy alone. These findings helped support the rationale for investigating a more advanced construct designed to express a CD40 agonist. However, the earlier product and NG-350A are different investigational medicines, and their clinical results cannot be combined as though they came from one treatment.
The development progression reflects a strategy of adding immune-stimulating functionality to a tumor-selective viral backbone. A conventional oncolytic approach can potentially damage malignant cells through viral replication, while NG-350A is intended to add local CD40-mediated immune activation. Whether this produces a clinically important advantage is the central question.
The company has obtained FDA Fast Track designation for NG-350A in mismatch repair-proficient locally advanced rectal cancer. The designation recognizes a development programme addressing a serious condition and may facilitate regulatory interactions. It does not establish that the treatment is effective or guarantee eventual approval.
The previous studies therefore support continued investigation, but the full FORTRESS analysis and subsequent randomized trial remain necessary to determine the value of the current candidate.
What must the planned Phase 2 randomized trial demonstrate?
Akamis expects to report FORTRESS topline results during the first half of 2027. Subject to regulatory discussions, it plans to initiate a randomized Phase 2 study in the second half of the year. The proposed investigation would evaluate NG-350A alongside chemoradiotherapy in a controlled setting.
The randomized design is important because it could distinguish treatment-related differences from the effects of patient selection or variation in standard care. It would also allow investigators to evaluate the combination’s safety relative to an appropriate control regimen. The exact design, enrollment target and statistical endpoints have not yet been announced.
A successful next-stage programme would need to demonstrate a meaningful improvement in outcomes beyond the initial 12-week composite response measure. Durability, disease control and the potential to preserve rectal function may become increasingly important. The benefit must also justify any additional treatment burden associated with introducing an intravenous oncolytic immunotherapy.
Manufacturing and operational considerations will matter as development expands. Engineered viral products require appropriate controls governing identity, potency, purity and consistent production. A trial involving more centers and patients will test whether the treatment can be delivered reliably alongside a conventional chemoradiotherapy regimen.
The regulatory path will depend on the clinical evidence generated and the FDA’s assessment of the proposed treatment setting. Fast Track designation may support communication but cannot replace the need for suitable efficacy and safety data.
What does completed enrollment mean for Akamis Bio’s oncology strategy?
Completing recruitment of 33 patients across seven sites is an important operational milestone for a privately held clinical-stage company. It gives Akamis a defined population from which to generate a more mature Phase 1b dataset and plan the next development stage. However, enrollment alone does not establish whether the investigational therapy improves outcomes.
The initial 50% composite response in ten patients remains encouraging, particularly when considered against the company’s historical benchmark. Yet the full analysis could produce a different response estimate, and a single-arm comparison cannot establish causation. Results concerning toxicity, MRI response and circulating tumor DNA will also influence the interpretation.
The company’s immediate commercial opportunity is related to developing a treatment for pMMR rectal cancer, a population that has not demonstrated the same dramatic sensitivity to checkpoint inhibitor monotherapy as dMMR disease. A successful randomized programme could provide evidence supporting a new approach to increasing tumor response and potentially improving organ preservation.
Akamis has not disclosed a revenue forecast, expected launch date or financing transaction associated with the October enrollment announcement. Its future value depends on the successful completion of clinical development and regulatory requirements rather than an immediate commercial event.
FORTRESS now moves from recruitment toward the collection and analysis of its full efficacy and safety dataset. The first-half 2027 results will determine whether the preliminary signal is sufficiently convincing to justify the planned randomized Phase 2 trial. Until then, NG-350A remains an investigational immunotherapy with a scientifically plausible mechanism and encouraging early activity, but without controlled evidence proving that it improves rectal cancer outcomes.
