ALX Oncology is reevaluating the potential of its anti-CD47 drug in the context of solid tumors, buoyed by promising data. The biotech revealed a 52% response rate among patients treated with its therapy, compared to 22% in the control group. This encouraging outcome has prompted ALX Oncology to explore opportunities for its asset in patients who have progressed after receiving medications like Enhertu and Keytruda.
Earlier this year, ALX halted two clinical trials for blood cancer involving its CD47-blocking fusion protein, evorpacept, which had initially generated significant enthusiasm in the oncology field. Despite setbacks in blood cancer studies, ALX, along with its competitor Gilead Sciences, has persisted in investigating the potential of these drugs in solid tumors.
The recent interim phase 2 results have given ALX confidence to pursue its solid tumor program further. These results showed that adding evorpacept to trastuzumab, Eli Lilly’s Cyramza, and paclitaxel led to a significantly higher objective response rate (ORR) in HER2-positive advanced gastric/gastroesophageal junction (G/GEJ) patients. In a study involving 54 patients receiving second and third-line treatment for G/GEJ, those receiving the three-drug regimen plus evorpacept experienced a 30 percentage point higher ORR compared to the control group. Additionally, there were early indications of extended response duration, with the median duration of response not yet reached in the evorpacept arm.
It’s worth noting that the response rate in the control arm was lower than what has been observed in other studies with these drugs. For instance, an open-label trial earlier this year demonstrated a 54% ORR with trastuzumab, ramucirumab, and paclitaxel as second-line therapy in HER2-positive advanced G/GEJ cancer patients.
Comparing data from different trials is complicated by variations in trial design and patient populations. ALX highlighted that its trial was the first global randomized study in HER2-positive gastric cancer to include participants who had previously received Merck & Co.’s Keytruda and AstraZeneca and Daiichi Sankyo’s Enhertu. Many participants in the trial had prior exposure to Enhertu and checkpoint inhibitors.
The positive responses observed in previously treated patients suggest that evorpacept could have a role in individuals who progress after first-line therapy. ALX plans to validate this hypothesis by releasing the final analysis of the phase 2 study in the second quarter of 2024 and subsequently launching the phase 3 portion of the trial.
The biotech is gearing up for a significant phase in its solid tumor research, planning to initiate the phase 3 trial in the second half of the next year. During this six-month period, ALX will also present data from two phase 2 trials in head and neck squamous cell carcinoma and from phase 1b studies in urothelial carcinoma and breast cancer. These developments signal an exciting phase in ALX Oncology’s pursuit of novel treatments for solid tumors.