Biotech Lagged The Broader Market In September — Did Retail Favorites SLS, IBRX, VNDA And IOVA Dodge XBI’s Slump?

• Sellas reported preclinical pancreatic cancer findings for SLS009 as investors awaited the Phase 3 Regal leukemia readout for GPS.
• ImmunityBio highlighted potential Anktiva applications and a January FDA decision, while Soon-Shiong’s blockchain tease fueled unconfirmed IBRX tokenization speculation.
• Iovance raised revenue guidance to $410 million-$420 million, while Vanda’s Hetlioz met its Phase 3 trial goal. 

Biotech stocks trailed the S&P 500 and Nasdaq-100 in September, yet Iovance Biotherapeutics (IOVA) and ImmunityBio (IBRX) bucked the sector’s decline, while Sellas Life Sciences (SLS) awaited key leukemia data and Vanda Pharmaceuticals (VNDA) unveiled a late-month sleep-drug trial win.

So far this month, the SPDR S&P Biotech ETF (XBI) fell 3.5%, compared with a 0.1% decline for the SPDR S&P 500 ETF Trust (SPY), a 3.1% gain for the Invesco QQQ Trust (QQQ), which tracks the Nasdaq-100, and a 3.3% drop for the SPDR Dow Jones Industrial Average ETF Trust (DIA).

Among the retail favorites, SLS fell 14%, IBRX gained 11%, IOVA climbed 77% and VNDA declined 7% in September.

All four attracted larger Stocktwits followings over the past year: watcher counts increased 34% for SLS, 58% for IBRX, 18% for IOVA and 60% for VNDA.

SLS Adds Cancer Data As GPS Wait Continues

Sellas showcased preclinical pancreatic cancer findings for SLS009, or Tambiciclib, at September’s AACR conference. In lab-grown tumor models made from patient samples that resisted Daraxonrasib, SLS009 triggered cancer-cell death in 17.9% of cells, compared with 2.8% for Daraxonrasib. Combining the drugs raised that figure to 36.5%. Pairing SLS009 with ZEN3694 also produced stronger effects than either drug alone in models driven by MYC, a gene that promotes cancer growth.

Investors are still awaiting the Phase 3 Regal leukemia readout for galinpepimut-S (GPS). The final analysis requires 80 deaths; as of May 11, the last update Sellas gave, 78 had occurred. Once the threshold is reached, the data must be reviewed and analyzed before releasing results.

On Stocktwits, sentiment for SLS was ‘bearish’ over the past month as message volume fell 7%, even as the ticker’s watcher count grew 3%. 

Anktiva Expansion And Tokenization Talk Keep IBRX In Focus

ImmunityBio’s September headlines included a patent application outlining potential uses of Anktiva to restore immune cells depleted by cancer treatment, alongside appearances at major lung-cancer and investment conferences. Anktiva is approved with BCG for certain U.S. bladder cancers. An application to expand its label to papillary-only disease carries a Jan.6, 2027 FDA decision date. 

Founder Patrick Soon-Shiong fueled retail speculation that IBRX shares could eventually be tokenized, represented and traded on a blockchain after posting: “The future is here. Watch this space as we launch blockchain and tokenized stocks at Nant.” He did not announce plans to tokenize ImmunityBio shares. 

On Stocktwits, IBRX sentiment rebounded to ‘bullish’ from ‘neutral’ a day ago, though below ‘extremely bullish’ a week earlier. Monthly message volume rose 12%, while watchers increased 1%. 

VNDA Caps September With Phase 3 Sleep-Drug Win

Vanda announced positive Phase 3 results on Tuesday for Hetlioz in delayed sleep-wake phase disorder, which shifts the body clock and sleep timing later.

Over 28 days, treated patients fell asleep 42.5 minutes earlier, versus 5.4 minutes with placebo, marking a 37.1-minute difference that met the primary endpoint. In an exploratory analysis, 60% advanced sleep onset by at least 30 minutes, compared with 15% on placebo. The trial enrolled 43 patients, with 20 per group included in the reported efficacy analysis. Vanda plans to seek an additional FDA indication for Hetlioz, already approved for two other circadian sleep disorders. 

On Stocktwits, VNDA sentiment climbed to ‘extremely bullish’ from ‘bullish’ a month ago, after swings through ‘bearish’ and ‘neutral’. Watchers increased 0.3% over the month. 

IOVA Revenue Upgrade Sends Shares Higher

Iovance raised its 2026 revenue outlook Tuesday to $410 million-$420 million from $350 million-$370 million, citing strong demand for Amtagvi and Proleukin. The new midpoint is $55 million higher and implies nearly 60% annual growth.

“Increasing patient demand and our current manufacturing schedule provide strong visibility into our third and fourth quarter revenues,” CEO Frederick Vogt said. The company has 100 authorized treatment centers and targets at least 110 by year-end. 

Amtagvi uses a patient’s own tumor-derived immune cells, expanded and returned to fight cancer. It received accelerated FDA approval in 2024 for previously treated advanced melanoma. H.C. Wainwright analyst Joseph Pantginis raised his price target to $20 from $9 and maintained a ‘Buy’ rating, implying about 38% upside from current levels. He said stronger commercial trends supported higher near- and longer-term estimates.

On Stocktwits, IOVA sentiment swung to ‘extremely bullish’ from ‘bearish’ a month ago as monthly message volume surged 168% and watchers climbed 3%. 

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