Promising Clinical Data and Ongoing Trials Justify Buy Rating for Exelixis’s Zanzalintinib

William Blair analyst Andy Hsieh has maintained their bullish stance on EXEL stock, giving a Buy rating today.

Andy Hsieh has given his Buy rating due to a combination of factors, primarily focusing on the promising clinical data from Exelixis’s zanzalintinib. The results from the Phase Ib STELLAR-002 trial, presented at the 2025 ASCO annual meeting, showed a strong response rate in combination with Opdualag for frontline clear-cell renal cell carcinoma, which is comparable to the efficacy of the parent compound, Cabometyx.
Furthermore, Hsieh is optimistic about the ongoing Phase III studies, STELLAR-303 and STELLAR-304, which are expected to yield positive results in the latter half of the year. These studies target third-line colorectal cancer and treatment-naïve non-clear-cell RCC, respectively. The consistent performance of zanzalintinib in clinical trials underpins the confidence in Exelixis’s potential for future success, justifying the Buy rating.

According to TipRanks, Hsieh is a 4-star analyst with an average return of 5.5% and a 44.81% success rate. Hsieh covers the Healthcare sector, focusing on stocks such as Skye Bioscience, Exelixis, and Cardiff Oncology.