ASCO24: Summit highlights bispecific's victory over Keytruda in lung cancer, stock soars

Summit Therapeutics experienced a notable rebound this week with new trial results that revealed promising data for their PD-1/VEGF bispecific antibody, ivonescimab, in patients with PD-L1-positive non-small-cell lung cancer (NSCLC). This came after a previous downturn linked to disappointing outcomes in a different trial for their lead candidate targeting EGFR-mutant NSCLC.

On Thursday, Summit's shares surged by an astonishing 272%, translating to a $5.6 billion increase in market capitalization. This significant jump followed the announcement that ivonescimab had shown superior progression-free survival (PFS) compared to Merck & Co.’s well-known PD-1 inhibitor, Keytruda (pembrolizumab), in a separate cohort of patients.

The initial data that triggered last week's plummet pertained to an abstract presented prior to the American Society of Clinical Oncology (ASCO) conference. This abstract indicated that a combination of ivonescimab and chemotherapy resulted in a median PFS of 7.06 months for patients with EGFR-mutant NSCLC, compared to 4.80 months in the control group. These results were underwhelming, leading to a more than 20% drop in Summit’s stock value, making it one of the largest declines in the biotech sector preceding the ASCO conference.

Despite this setback, the ivonescimab-chemotherapy combination garnered approval in China, where Akeso, a partner holding marketing rights, conducted the trial. Summit had earlier secured the licensing rights for ivonescimab in the US, Canada, the EU, and Japan in 2022, investing $500 million upfront for this agreement.

The recent rise in Summit’s stock is attributed to positive outcomes from the Chinese Phase III HARMONi-2 trial, sponsored by Akeso. While specific numerical data were not shared, Summit announced that ivonescimab monotherapy achieved a statistically significant and clinically meaningful improvement in PFS compared to Keytruda monotherapy for patients with PD-L1-positive, locally advanced, or metastatic NSCLC.

Summit’s Chief Executive, Maky Zanganeh, stated, “HARMONi-2 clearly demonstrates that ivonescimab is the next generation in PD-1 directed immunotherapy.” The company is set to hold a conference call on June 3 to delve deeper into the details of ivonescimab and the data that will be presented at the ASCO conference.

The recent turnaround in Summit’s fortunes underscores the volatile nature of the biotech sector, particularly as it hinges on clinical trial outcomes. The initial disappointment over the EGFR-mutant NSCLC data showcased the challenges and risks inherent in drug development. However, the subsequent positive results from the HARMONi-2 trial highlight the potential for significant rebounds when new data emerge, reinforcing investor confidence and market performance.

In summary, Summit Therapeutics has managed to recover impressively with promising new trial results for ivonescimab in PD-L1-positive NSCLC patients. This recovery underscores the importance of continuous research and the dynamic nature of biotech investments, where each clinical trial outcome can significantly sway market positions and investor sentiment.