The stock of Legend Biotech (LEGN) experienced a significant single-day surge of over 40% on June 2nd, following a notable rally earlier in the year. This event marks a period of substantial market revaluation for the company.

From Rebound to Rapid Ascent

On April 20th, Eli Lilly announced a potential $7 billion acquisition of Kelonia, a company focused on an in vivo CAR-T platform technology known as iGPS. This major deal intensified the competitive landscape in the in vivo CAR-T sector. Legend Biotech benefited from this news as the acquisition highlighted the significant value and potential that major pharmaceutical companies see in this emerging therapeutic approach.

The core appeal of Kelonia's platform is its theoretical versatility across different CAR designs, targets, and diseases. However, the technology's clinical data, particularly for its lead candidate KLN-1010, remains early-stage, based on a small patient group with limited follow-up. Lilly's substantial investment underscores a bet on the platform's future potential to overcome traditional CAR-T manufacturing and cost hurdles.

At the time of the Lilly-Kelonia news, Legend Biotech had a market capitalization under $4 billion, far less than the $7 billion deal value. This discrepancy suggested the market was undervaluing Legend Biotech, which possesses an established commercial CAR-T product. This perception of undervaluation contributed to the stock's rise around April 20th.

In the short term, driven by corporate developments and market sentiment, the company's stock climbed over 40% in a period, accompanied by rising trading volumes—a classic sign of increased buying interest. From a longer-term technical perspective, after a prolonged downtrend, the stock had been consolidating at lower levels since February with reduced selling pressure.

This period allowed for accumulation of shares by larger investors. The significant price increase on April 20th, on high volume, helped the stock break out of this consolidation pattern, forming a technical signal often interpreted as bullish for medium to long-term prospects. Following this, the stock trended higher with positive market sentiment, trading consistently in the upper half of its Bollinger Bands range with sustained volume.

Analysis of shareholder positioning showed that despite new investors entering at higher prices, a core base of earlier investors largely held their positions, indicating continued control by major stakeholders. The dramatic 42.22% surge on June 2nd provided an opportunity for these investors to realize profits.

Do All In Vivo CAR-T Candidates Warrant Similar Valuations?

The June 2nd surge was directly tied to Legend Biotech's announcement of initial clinical data for its in-house, in vivo CD19/CD20 dual-targeting CAR-T therapy, LB2501. The data, from a small Phase I study in patients with relapsed/refractory B-cell non-Hodgkin lymphoma, showed an impressive 100% overall response rate and an 83.3% complete response rate, with no severe adverse events or dose-limiting toxicities observed.

The market's enthusiastic reaction stems from these early results appearing superior in efficacy to already approved CAR-T therapies for the same condition, such as Yescarta and Tecartus. Crucially, LB2501 is an in vivo therapy, designed to generate CAR-T cells directly inside the patient's body after a single infusion, bypassing the complex and costly external cell manufacturing process of traditional CAR-T.

However, this early promise comes with caveats typical of initial studies: a small sample size, short follow-up duration, and lack of longer-term data on progression-free survival. The field has seen setbacks before; for instance, Caribou Biosciences saw its stock plummet after a patient relapse was reported following initially positive data for its off-the-shelf CAR-T candidate.

Therefore, for Legend Biotech to solidify the valuation boost from its in vivo CAR-T program, demonstrating durable responses from LB2501 in longer and larger studies will be critical. Nevertheless, the data has successfully challenged the market's previous perception of the company as a single-product story reliant solely on its blockbuster therapy, Carvykti.

For the company, expanding its valuation narrative beyond one product is strategically more important than short-term stock price spikes. Following the June 2nd surge, the stock price corrected over the next two trading sessions. Despite the pullback, trading volume decreased significantly, and a substantial portion of shares remained held at price levels below $20. For long-term investors, the recent surge may represent just the beginning of a broader re-rating for Legend Biotech.