AbbVies stock $ABBV is getting hammered this morning after its $10 billion Rova-T program posted poor mid-stage results for third-line small cell lung cancer, forcing the company to scuttle any plans to seek an accelerated approval for the closely-watched drug after talks with skeptical regulators.

After fanning hopes amid considerable skepticism in some circles with its projections of a blockbuster future for Rova-T, investigators outlined a 16% objective response rate and median overall survival of 5.6 months for the drug.

Shares cratered on the terse release, free falling 12% and wiping more than $20 billionoff its market cap, which started the day at $178 billion.

The magnitude of the ORR for the DLL3-high group was dismal, leaving the future of the drug in doubt. And by implication, some analysts are wondering just how bad the data are for the full group, expecting the read out to be even worse.

By focusing on DLL3-expressing cancers, the market was expecting an ORR in the 40% range. Chemo combos are in the 20% area, analysts note, and IO combos are also demonstrating efficacy. So with an IRC assessment at 16%, AbbVie is well behind the 8 ball, with the FDA chilling talk of an accelerated approval despite the fact that there are no approved options.

Severe adverse events were recorded for thrombocytopenia (11%), photosensitivity reaction (7%) and pleural effusion (5%).

AbbVie paid $5.8 billion in cash for this drug, promising up to $4 billion more in milestones to acquire the little-known biotech unicorn Stemcentrx. And with money like that on the table, expectations were running high, fueling forecasts that the pharma company could get past the eventual loss of patent protection on Humira in style.

Today, AbbVie is feeling the lash of disappointed analysts. Heres Geoffrey Porges:

Oncology is the key growth business segment for AbbVie after the loss of exclusivity for Humira in 2023, and todays results and regulatory decision call into question the viability of the companys current solid tumor strategy.

Combined with Bristol-Myers Opdivo and Yervoy, AbbVie was betting that it had a winner in small cell lung cancer, though its first cut of the early data last year failed to impress anyone outside of the company. The drug drops a cytotoxic bomb right on DLL3-expressing cancer cells common in SCLC.

We continue to believe Rova-T has potential for patients with small cell lung cancer and other DLL3-expressing cancers, said Mike Severino, executive vice president of research and development and chief scientific officer, AbbVie. Although the results from the study were not what we hoped for, we look forward to receiving data from the ongoing Phase 3 studies in the first- and second-line settings and remain committed to developing Rova-T for the treatment of patients with small cell lung cancer.