Pfizer (PLTR) has reportedly decided to sell its entire remaining stake in Biontech (BNTX), showing a lack of confidence in Biontech’s Covid vaccine and in BNTX stock. Meanwhile, Biontech has generally been generating relatively steep losses and its shares are not cheap. Finally, while its two most prominent drug candidates show some potential, they both have significant weaknesses and consequently may very well not end up generating large amounts of revenue for the firm.
In light of these points, I recommend that investors sell BNTX stock.
About BioNTech
In partnership with Pfizer, BNTX developed one of the leading vaccines for Covid. Based on mRNA technology, the shot, known as Comirnaty, generated peak sales of $37.8 billion in 2022. However, the vaccine’s sales have dropped a great deal subsequently. In Q3 of 2025, it generated $1.15 billion of revenue, representing a year-over-year decline of about 19%, Pfizer reported.
As a result, Biontech, which had generated very high profits in 2022 and was significantly profitable in 2023, has fallen fairly deep into the red. In 2024, it reported a net loss of $719.9 million, while its net loss in the third quarter of 2025 was $33.55 million. However, in Q3 the company’s bottom line was tremendously boosted by payments from Bristol-Myers Squibb (BMY) that BNTX received. The payments are related to the companies’ collaboration on BNT327, an immuno-oncology treatment, and the upfront portion of the payments will amount to $1.5 billion. However, BNTX will receive another “$2 billion total in non-contingent anniversary payments through 2028” and can obtain up to an additional $7.6 billion in payments if the drug attains certain “development, regulatory and commercial” milestones.
Still, Biontech looks poised to generate significant losses for some time. Indeed, analysts on average expect it to report a loss per share of $4.10 in 2025 and a loss per share of $4.04 in 2026.
The shares are changing hands at a price-sales ratio of 6.8 times.
Assessing the Company’s Two Most Prominent Pipeline Drugs
The two drugs in BNTX’s pipeline that have received the most attention in the media and from the company itself (based on an analysis of its press releases and of the transcript of its third-quarter earnings call) are BNT327 and BNT323, which “is based on … a type of high-precision chemotherapy.”
In a Phase 2 clinical trial,”patients with extensive stage small cell lung cancer” received BNT327, also known as Pumitamig, The median progression-free survival (PFS) rate among 38 patients for whom data was reported was 6.8 months., Among patients who received a dose of 20 mg/kg, the median PFS was 6.3 months, while median PFS climbed to 7 months among the patients who received a higher dose of 30 mg/kg. According to Google AI overview, “the average Progression-Free Survival (PFS) for extensive-stage small-cell lung cancer (ES-SCLC) is generally between 4.5 and 6.2 months.” So it appears that the patients who received the lower dose of Pumitamig did not exceed the upper end of the range by a significant amount. And the patients who received the higher dose did not exceed the upper end of the PFS level by a great deal.
Also importantly, indicating that there may be safety issues at the higher levels, five patients in the latter category reported adverse events (AEs) of “grade 3 or higher.” Specifically, among the patients who received the higher dose, there were reportedly “two cases of hypertension, and one case apiece of decreased platelet count, proteinuria and pulmonary embolism.”
Given the low increase in PFS and the worrisome AE rate among the higher-dose cohort, I think, at best, that the jury is still out on Pumitamig.
As for BNT323, the drug, in encouraging news, met its primary endpoint involving PFS in a trial involving breast cancer patients, according to the interim analysis of a Phase III trial whose results were reported by BNTX in September. However, BNT323 will be competing with Enhertu, a similar drug that has already been approved by the FDA. Often, it’s difficult for newly approved drugs to compete with treatments that have entered the market much earlier, unless the newer treatment has a significant advantage over its counterpart. And since BNTX’s drug is based on similar technology as that of Enhertu, BNTX’s offering is unlikely to have such a major advantage. Therefore, BNT323’s sales may wind up disappointing the Street.
The Bottom Line on BNTX
Pfizer presumably has high-quality information regarding the current and future demand for BioNTech’s Covid vaccine and may also have a great perspective on the drugs in BNTX’s pipeline. Therefore, Pfizer’s apparent decision to sell its remaining stake in BNTX does not bode well for the firm’s outlook.
Meanwhile, Biontech is losing money. And while BMS’ decision to invest a large amount in the company and Pumitamig is encouraging, I don’t believe that the data on the drug was especially strong. Further, BNT323 will have to compete with a similar drug with a major first-mover advantage, and BNTX’s valuation is not particularly low.
So BNTX does look like a sell for now. However, depending on the progress of the firm’s drug candidates, the shares may be worth buying in the future, particularly if the price of BNTX stock drops a great deal.
