Analysts Sound Alarm On Pyxis Oncology's Tiny Trial

Pyxis Oncology Inc. (NASDAQ:PYXS) on Thursday released preliminary data from its ongoing Phase 1 studies of micvotabart pelidotin (MICVO) for recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). The update includes preliminary data from both the Phase 1 monotherapy study in second line (2L+) R/M HNSCC and the Phase 1/2 study evaluating MICVO in combination with Merck & Co. Inc.’s (NYSE:MRK) Keytruda (pembrolizumab), in (first and second line) 1L/2L+ R/M HNSCC. The data reported below reflect outcomes as of the November 3, 2025, cutoff. Also Read: Merck’s Keytruda Secures FDA Nod For Head And Neck Cancer As First Immunotherapy For Use Around Surgery In the monotherapy cohort, the confirmed overall response rate was 46% (6 of 13 patients), including one complete response. The disease control rate reached 92% (12 of 13 patients), with 12 patients demonstrating significant tumor regression or tumor control. MICVO was generally well tolerated, with no Grade 4 ADC payload treatment-related adverse events (TRAEs) of interest observed. No Grade 5 events occurred. In the combination therapy cohort, the confirmed overall response rate was 71% (5 of 7 patients), with responses observed in patients who had previously received checkpoint inhibitor therapy and experienced disease progression. The disease control rate was 100% (7 of 7 patients), with all seven patients demonstrating significant tumor regression. MICVO Next Steps In mid-2026, Pyxis Oncology plans to present updated data from the ongoing Phase 1 monotherapy study in 2L+ R/M HNSCC. In the second half of 2026, the company also plans to present updated data from the ongoing Phase 1/2 study evaluating MICVO in combination with pembrolizumab. The company is currently evaluating the path forward to pivotal studies for MICVO as monotherapy and in combination with pembrolizumab, respectively, and expects to provide additional details in 2026. Company Update Pyxis Oncology completed the sale of its rights to royalties from the commercialization of Enzeshu (Suvemcitug for Injection) for a one-time cash payment of $11 million. The non-dilutive funding will support the development of MICVO, and the company’s current cash runway is expected to fund operations through data milestones and into the fourth quarter of 2026. Pyxis Oncology shares closed down about 49% at $1.73 on Thursday. William Blair said the selloff reflects concerns over limited data interpretability, as the update added only nine new monotherapy patients since November 2024. Analyst Andy T. Hsieh also highlighted tolerability issues, citing a 28% discontinuation rate, well above the typical 10%–15% seen in oncology trials, and shrinking cash reserves, with a runway into the fourth quarter of 2026 and no major catalyst expected until mid-2026. “Given the difficulty in drawing solid conclusions regarding Micvo’s efficacy and competitive differentiation, and the uncertainties associated with durability of response and tolerability, against the backdrop of continued cash burn, we are reiterating our Market Perform rating on Pyxis shares,” William Blair wrote on Thursday. “While we are encouraged by the response rate, the small sample size (13 patients for monotherapy and 7 patients for the combination cohort) adds considerable uncertainty regarding the precision of reported metrics.” PYXS Price Action: Pyxis Oncology shares were up 0.62% at $1.74 during premarket trading on Friday, according to Benzinga Pro data. Read Next: Parsons Lands $100 Million Defense Deal To Boost US Munitions Output Image via Shutterstock