Cardiff Oncology's Colorectal Cancer Trial Results Spark Investor Concern

Cardiff Oncology's latest update on its phase 2 colorectal cancer trial has sent ripples through the pharmaceutical industry, prompting a significant drop in the company's stock price. The trial, which is testing the PLK1 inhibitor onvansertib in combination with standard care for patients with first-line RAS-mutated metastatic colorectal cancer (mCRC), has yielded results that have left investors questioning the drug's potential.

Updated Trial Data Narrows Efficacy Gap

The most recent data cut from Cardiff's phase 2 study has revealed a narrowing gap between the treatment and control arms. Including unconfirmed responses, the objective response rate (ORR) for the high-dose arm was 59%, compared to 43% in the control arm. When excluding unconfirmed responses, the ORRs were 49% and 30% for the high-dose and control arms, respectively. This difference falls short of Cardiff's targeted 20% improvement, as noted by William Blair analysts.

These results contrast with the more promising data reported in December, which showed a 64% ORR for the high dose versus a 33% ORR in the control cohort. The narrowing of this gap has contributed to investor skepticism, reflected in the 27% drop in Cardiff's share price to $2.43 in premarket trading.

Company Optimism Amidst Investor Skepticism

Despite the market's reaction, Cardiff's CEO Mark Erlander remains optimistic about onvansertib's prospects. In a conference call with analysts, Erlander stated that the data support "the next step in our path towards a seamless registrational trial for both accelerated and full approval." He emphasized that the high dose is "clearly outperforming" the control group and that the results compare "favorably against previous practice-changing trials."

Erlander also highlighted the importance of early indicators such as tumor shrinkage, early responses, and depth of response, which he believes are strongly correlated with improvements in progression-free survival (PFS). While the PFS data is still immature, with a median follow-up of six months, the CEO expressed confidence in the emerging trends.

Looking Ahead: Regulatory Discussions and Future Updates

Cardiff Oncology is now preparing for potential discussions with the FDA regarding a registrational program. Erlander indicated that the company would make a decision on approaching the FDA within the next month or two, suggesting that management believes they have sufficient evidence to move forward with regulatory talks later this year.

The company plans to provide an update on the first-line mCRC program in the first quarter of next year. This update is expected to include more mature PFS data, which could provide a clearer picture of onvansertib's impact on patient outcomes.

As the pharmaceutical industry watches closely, the coming months will be crucial for Cardiff Oncology as it navigates the path forward for onvansertib in the competitive landscape of colorectal cancer treatments.