Curis, Inc. reported an expanded set of clinical responses for emavusertib in relapsed or refractory primary central nervous system lymphoma, alongside faster-than-expected patient consent activity in a separate chronic lymphocytic leukemia study. The update gives the Nasdaq-listed biotechnology company additional evidence that combining emavusertib with a Bruton tyrosine kinase inhibitor may produce responses in patients whose disease has already progressed on that drug class.
In the TakeAim Lymphoma study, 10 of 30 evaluable BTK inhibitor-experienced patients achieved an objective response, producing a company-reported objective response rate of 33%. When all 39 treated patients were included, regardless of whether they completed at least one treatment cycle, the response rate was 26%. The previous May 2025 update showed seven responses among 26 patients, or 27%, on an all-patient basis.
That distinction matters. Curis has increased the absolute number of responses from seven to 10 as the dataset expanded, but the response rate among all treated BTK inhibitor-experienced patients has remained broadly unchanged. The updated result is therefore more convincing as evidence of repeatable activity than as evidence that efficacy is improving with longer follow-up.
The smaller BTK inhibitor-naïve cohort produced a stronger headline percentage. Five of five evaluable patients responded, while six of all seven treated patients were reported as responders, representing an 86% all-patient objective response rate. That compared with five responses among seven patients, or 71%, in the earlier update.
Emavusertib remains investigational and has not been approved for primary central nervous system lymphoma, chronic lymphocytic leukemia or any other indication. The July 22 disclosure provided response counts but did not include a new safety analysis, response-depth breakdown, duration-of-response figures, progression-free survival or overall survival data. Those omissions limit how far the updated percentages can be interpreted.
What do the expanded PCNSL response numbers reveal about emavusertib’s clinical signal?
TakeAim Lymphoma is evaluating oral emavusertib with ibrutinib in patients with relapsed or refractory primary central nervous system lymphoma. Part A, which examined dose escalation, has been completed. Part B is an ongoing single-arm study involving patients previously treated with a BTK inhibitor, while Part C is evaluating the combination in a randomized BTK inhibitor-naïve population.
The BTK inhibitor-experienced population is arguably the more commercially and clinically important group. Curis is attempting to show that adding emavusertib immediately after progression on a BTK inhibitor can restore disease control by blocking a separate signalling pathway. Patients whose disease progresses after BTK inhibition have limited treatment options and can deteriorate rapidly because primary central nervous system lymphoma affects the brain, spinal cord or related structures.
The increase from seven to 10 responses supports the argument that earlier observations were not confined to only a few isolated cases. Nevertheless, investors and regulators will notice that the all-patient response rate remained effectively flat as the cohort expanded. This is not inherently negative. Maintaining a response rate while adding more patients can strengthen confidence in an early signal. It does, however, mean that the most defensible interpretation is consistency rather than a dramatic improvement.
The evaluable response rate of 33% excludes nine patients who had not completed at least one cycle, approximately one month, of treatment. The all-patient analysis is more conservative because it retains those patients in the denominator. Future updates will need to explain what happened to those initially unevaluable patients and whether additional responses emerge after sufficient exposure.
The BTK inhibitor-naïve data are encouraging but statistically fragile. With only seven patients, one additional response or non-response can materially change the percentage. The randomized portion of TakeAim Lymphoma should provide a more useful assessment of how much emavusertib contributes beyond ibrutinib alone.
Why could dual BCR and TLR pathway blockade work after BTK inhibitor progression?
Curis is developing emavusertib as an orally available small-molecule inhibitor of IRAK4 and FLT3. In primary central nervous system lymphoma and chronic lymphocytic leukemia, dysregulated NF-kB signalling can be supported by both the B-cell receptor pathway and the Toll-like receptor pathway.
BTK inhibitors target signalling associated with the B-cell receptor pathway. Emavusertib is intended to suppress IRAK4-mediated signalling through the Toll-like receptor pathway. Curis’ strategy is therefore based on blocking two biological routes that can support NF-kB activity, cancer-cell survival and treatment resistance.
This dual-blockade rationale gives the combination a coherent biological foundation, particularly when emavusertib is introduced directly after progression on a BTK inhibitor. The clinical question is whether that mechanistic logic consistently translates into deep, durable responses without creating unacceptable additive toxicity.
Objective response rate alone cannot answer that question. Regulators will want to understand how many responses are complete rather than partial, how long they last, whether neurological function is preserved, how frequently patients discontinue treatment and whether adverse events compromise dose delivery.
Could the current TakeAim Lymphoma study support an accelerated regulatory filing?
Curis previously discussed the development programme with the U.S. Food and Drug Administration and the European Medicines Agency’s Committee for Medicinal Products for Human Use. According to the company’s regulatory disclosures, both agencies indicated that the ongoing single-arm study could potentially support an accelerated pathway, subject to the strength and consistency of the completed dataset.
European scientific advice indicated that approximately 45 patients could be sufficient for a conditional marketing authorisation submission if results were compelling and consistent. Overall response rate could serve as the primary endpoint, although the size of the safety database would remain a review issue.
The U.S. Food and Drug Administration indicated that overall response rate, supported by adequate response duration, could potentially support an accelerated approval submission. The agency did not commit to a required patient number and identified the size of the efficacy and safety dataset as a matter for review during the application process.
Curis must also address the contribution of each component of the combination. Regulators need evidence that the observed activity is not simply attributable to ibrutinib. The randomized BTK inhibitor-naïve cohort is particularly important for resolving that question, while the company must also analyse its 100-milligram and 200-milligram emavusertib doses before a potential U.S. submission.
Consequently, the updated response count helps the regulatory case but does not complete it. A path to submission is not equivalent to acceptance, approval or agreement that the existing evidence is sufficient.
Why is Curis accelerating the TakeAim CLL programme before mature PCNSL data arrive?
TakeAim CLL is an open-label Phase 2 study of emavusertib combined with zanubrutinib. It is enrolling chronic lymphocytic leukemia patients who have received zanubrutinib for at least 12 months but remain in a partial response or partial response with lymphocytosis and continue to have measurable residual disease.
The programme is designed to test whether adding emavusertib can deepen an existing response, potentially moving patients toward complete response or undetectable measurable residual disease. This differs from the primary central nervous system lymphoma strategy, where the company is evaluating whether emavusertib can reverse progression after BTK inhibitor treatment.
Curis said the number of consented TakeAim CLL patients had reached 10, up from six reported earlier in July. The company expects the first five patients to be dosed by the end of the month and has increased its December 2026 data guidance from five patients to a range of five to 10.
Consent should not be confused with treatment. Patients must still complete screening and meet protocol requirements before dosing. The December dataset will also be extremely early, particularly for endpoints such as complete response, measurable residual disease clearance, durability and safety.
Even so, stronger site participation and consent activity reduce one operational risk. Small biotechnology studies can lose valuable time when rare eligibility criteria slow recruitment. If Curis reaches the upper end of its December guidance, investors will receive a broader first look at the chronic lymphocytic leukemia strategy than previously expected.
Why do Curis’ funding position and recent reverse stock split still matter?
Curis ended March 2026 with $15 million in cash and cash equivalents and used $9 million in operating activities during the first quarter. The company reported a $24.2 million quarterly net loss, although that figure included substantial non-cash accounting effects associated with warrant liabilities.
Curis has acknowledged that its existing cash is insufficient to fund operations for 12 months from the filing date of its first-quarter report. It expects to require substantial additional capital to advance emavusertib through regulatory review and potential commercialisation.
The company raised approximately $18.6 million in net upfront proceeds through a January 2026 private placement. Additional funding could be generated through associated warrants, but those proceeds depend on investors choosing to exercise them. The fifth patient dosed in TakeAim CLL is also connected to the termination timetable for one warrant series, linking the clinical milestone with a potentially important financing event.
Curis completed a one-for-20 reverse stock split in early July, with split-adjusted trading beginning on July 6. The transaction increased the quoted price per share but did not by itself increase the company’s underlying value. It was an important Nasdaq listing measure and reflects the financing pressure surrounding the development programme.
Curis shares were trading near $4.90 in the afternoon on July 22, approximately 3% above the previous close. The stock was up roughly 4% over five trading days but remained down more than 40% over one month. Its split-adjusted 52-week range was approximately $3.61 to $39. The mixed performance suggests that investors welcomed the clinical update without overlooking dilution risk, limited liquidity and the company’s dependence on a single lead asset.
What must Curis show next for emavusertib to become a credible regulatory candidate?
The latest update is encouraging because the number of BTK inhibitor-experienced responders increased as the dataset expanded, while the BTK inhibitor-naïve group produced another response. It is not yet a decisive clinical inflection because the larger all-patient response rate remained broadly stable and the release did not provide the durability, response-depth or safety evidence required for a complete benefit-risk assessment.
The next meaningful tests are clearly defined. Curis must mature the 10 responses in previously treated primary central nervous system lymphoma patients, show whether they remain durable, complete the contribution-of-effect work requested by regulators and disclose a sufficiently detailed safety database. It must also demonstrate that the early operational momentum in TakeAim CLL translates into dosed, evaluable patients and clinically meaningful response deepening.
December’s initial chronic lymphocytic leukemia results could broaden emavusertib’s strategic value, but the primary central nervous system lymphoma programme remains the nearer regulatory opportunity. For Curis, the science has earned continued attention. The harder task is now to convert a promising response signal into durable evidence while securing enough capital to reach the regulatory finish line.
