Pyxis Oncology's Cancer Drug Progress Stirs Analyst Concerns

On Wednesday, Pyxis Oncology, Inc. PYXS released preliminary data from the ongoing Phase 1 clinical dose escalation study evaluating PYX-201 in multiple solid tumors.

Among evaluable Head and Neck Squamous Cell Carcinoma (HNSCC) patients treated at an identified dose range of PYX-201 from 3.6 – 5.4 mg/kg (n=6), a confirmed 50% objective response rate (ORR) was observed, including one confirmed complete response (CR) and two confirmed partial responses (PR).

The company additionally announced a Clinical Trial Collaboration Agreement with Merck & Co Inc MRK for a Pyxis Oncology-sponsored study of PYX-201 in combination with Merck’s Keytruda (pembrolizumab) in patients with 1L and 2L HNSCC, HR+/HER2- breast cancer, and triple-negative breast cancer (TNBC) and sarcoma.

• PYX-201 and Keytruda combination dose escalation and expansion study in 1L and 2L HNSCC with preliminary clinical data readout expected in the second half of 2025.
• PYX-201 monotherapy study in 2L and 3L HNSCC patients who are platinum and PD-1 inhibitor experienced, with preliminary clinical data readout expected in the second half of 2025.
• PYX-201 monotherapy study in 2L and 3L HNSCC patients who are EGFR and PD-1 inhibitor experienced, with preliminary clinical data readout expected in the first half of 2026.

Exploratory PYX-201 Phase 1 monotherapy expansion cohorts are planned for ovarian cancer, NSCLC, HR+/HER2 breast cancer, TNBC, and sarcoma. Preliminary clinical data are expected in the second half of 2025.

• The company also expects to initiate the PYX-201 and Keytruda combination study in HR+/HER2 breast cancer, TNBC, and sarcoma, with preliminary clinical data expected in the second half of 2025 and the first half of 2026.
• Preclinical studies of PYX-201 combined with other agents in ovarian cancer and NSCLC will commence in 2025, followed by clinical studies with preliminary clinical data expected in 2026.

PYX-201 demonstrated favorable preliminary tolerability profile data with low incidence of dose discontinuation, interruptions, or delays due to treatment-related adverse events.

William Blair analysts note that PYX-201 shows limited effectiveness outside of head-and-neck cancer, with only 8.7% of patients (2 out of 23) responding to tolerable doses of 3.6 mg/kg, 4.4 mg/kg, and 5.4 mg/kg.

“At this point, we are unsure whether the three unconfirmed responses could ultimately be confirmed,” the analysts writes.

The analysts has reduced the probability of success for PYX-201 to 10% from 35%. The updated fair value stands at $250 million or roughly $4.25 per share, comprising $1.77 per share from PYX-201 and $2.48 per share of cash.

With no major stock-moving events expected until the second half of 2025, the analysts estimate the stock will trade around $2.80 per share soon. William Blair says it includes $1.77 per share for PYX-201 and $1.07 for remaining cash by late 2025.

William Blair downgrades Pyxis to Market Perform, saying, “Since we view the head-and-neck cancer results as difficult to differentiate, coupled with modest activity in other solid tumor histologies.”

Price Action: PYXS stock is down 42.15% to $2.21 during premarket trading on Thursday.

Read Next:

• Qualcomm’s Shift From Handsets To AI And Automotive Wins Analysts’ Confidence

Image created using artificial intelligence via Midjourney.