Geron (GERN -31.43%) stock is getting crushed in Wednesday's trading. The company's share price was down 31.7% as of 3:50 p.m. ET and had been down as much as 38.7% earlier in the session.

Geron stock is seeing huge sell-offs on the heels of the company's recent fourth-quarter report and commentary. Despite sales for the period coming in ahead of the market's expectations, the business posted a wider-than-expected loss, and investors are seeing worrying signs for the performance of the company's Rytelo drug.

Geron stock sinks on weakening outlook for Rytelo

Geron posted a loss of $0.04 per share on sales of $47.54 million in Q4. Meanwhile, the average analyst estimate had called for the business to post a per-share loss of $0.02 on sales of $45.3 million. Making matters worse, the company's management said that it was seeing sales growth stall for Rytelo -- the company's drug for treating symptoms of anemia.

What's next for Geron?

Rytelo is Geron's lead treatment, and slowing sales for the drug suggest that the company's growth outlook has become significantly weaker than previously anticipated. Following the company's Q4 report, H.C. Wainwright downgraded its rating on Geron from buy to neutral. The firm didn't issue a new price target in conjunction with the downgrade, but it raised concerns about the company's product pipeline on the heels of weakening results for Rytelo.

Following today's pullback, Geron is now down roughly 17% over the last year. With sales momentum for the company's lead treatment weakening, the company's development pipeline has taken on added significance. In line with the shift, Geron stock has become a much more speculative bet.