This small-cap biotech stock is surging. Time to buy?Last Friday, Agenus (AGEN 40.84%), an immuno-oncology player, saw its shares soar by a staggering 40.8%. This remarkable rally occurred seemingly without a clear catalyst. The company is set to announce its first-quarter earnings for 2024 before the market opens on Tuesday, May 7. However, there's no certainty that the company will release any information that justifies this significant surge in its shares.So, what's causing all the excitement? Investors ...