Stock Market Today, March 16: CytomX Therapeutics Surges After Positive Phase 1 Colorectal Cancer Data

CytomX Therapeutics (CTMX +44.23%), a biotech company that develops conditionally activated biologics for cancer treatment, closed Monday at $6.75, up 44.23%. The stock is jumping after releasing Phase 1 Varseta-M data in metastatic colorectal cancer and subsequent upbeat analyst reactions. Investors will now be watching upcoming FDA interactions and further clinical readouts.
Trading volume reached 118 million shares, coming in about 2,211% above its three-month average of 5.1 million shares. CytomX IPO’d in 2015 and has fallen 48% since going public.

How the markets moved today

The S&P 500 (^GSPC +1.01%) rose 1.02% to 6,700, while the Nasdaq Composite (^IXIC +1.22%) added 1.22% to finish at 22,374. Within biotechnology, industry peers XOMA (XOMA +0.08%) closed at $26.61 (+0.87%) and Rigel Pharmaceuticals (RIGL +2.23%) finished at $26.55 (+2.31%), underscoring interest in drug developers.

What this means for investors

CytomX announced Phase 1 expansion data for varsetatug masetecan (also called Varseta-M), revealing objective response rates of up to 32% and progression-free survival of approximately seven months in late-stage metastatic colorectal cancer. This data bolsters their intentions to engage in FDA registrational trial discussions in 2026.

The biotech company also reported 2025 revenue of approximately $76 million, along with a net loss, and held cash reserves of around $137 million, providing financial runway into the second quarter of 2027. This offers investors clarity on funding for their ongoing oncology programs.  Company losses were wider than forecast, though, reminding investors that clinical progress still comes with meaningful financial risk.