Karyopharm Pursues Myelofibrosis FDA Milestone

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1. Ownership and Share Structure Information

The information listed above was updated on the date this article was published and was compiled from information from the company and various other data providers.

Life science investors watching the cancer drug sector are interested in Karyopharm Therapeutics Inc.'s (KPTI:NASDAQ) latest plans to an sNDA submission.

Key Takeaways

• Karyopharm plans to submit an sNDA (supplemental new drug application) to the U.S. Food and Drug Administration (FDA) in August 2026 for selinexor plus ruxolitinib in myelofibrosis, seeking accelerated approval.
• The FDA indicated SVR35 (≥35% spleen volume reduction) qualifies as a reasonably likely surrogate endpoint to support accelerated approval, based on feedback to the company.
• The submission is based on Phase 3 SENTRY trial data, which showed statistically significant SVR35 improvement at week 24 and a promising overall survival signal.
• Long-term overall survival data from SENTRY's ongoing, blinded follow-up will be used to verify clinical benefit.
• Karyopharm intends to request Priority Review, which would set a PDUFA target action date roughly six months after FDA receipt of the application.
• If approved, the combination would become the first approved combination therapy for myelofibrosis.

A New sNDA on the Horizon

On July 30, 2026, Karyopharm Therapeutics Inc. announced that it plans to submit an sNDA to the FDA in August 2026, requesting accelerated approval of selinexor in combination with ruxolitinib for the treatment of patients with myelofibrosis. According to the press release, myelofibrosis is a rare blood cancer affecting approximately 20,000 people in the U.S. and 17,000 people in the E.U. "The disease causes bone marrow fibrosis (scarring in the bone marrow), which makes it difficult for the bone marrow to make healthy blood cells, splenomegaly (enlarged spleen), progressive anemia which often leads to symptoms like fatigue and weakness, and other disease associated symptoms including abdominal discomfort, pain under the left ribs, early satiety, night sweats and bone pain," the company said. Currently, the only approved therapies are JAK inhibitors, which include ruxolitinib.

The planned filing follows discussions with the FDA, which indicated that achieving at least a 35% reduction in spleen volume (SVR35) appears to qualify as a reasonably likely surrogate endpoint for overall survival under the agency's accelerated approval pathway. Karyopharm said it plans to use long-term overall survival data from the ongoing Phase 3 SENTRY trial to confirm clinical benefit following any accelerated approval.

"The SENTRY trial generated one of the most compelling frontline datasets in myelofibrosis to date," said Dr. John Mascarenhas, Professor of Medicine at the Icahn School of Medicine at Mount Sinai and Director of the Center of Excellence for Blood Cancers and Myeloid Disorders. "The combination of selinexor and ruxolitinib demonstrated compelling spleen responses across a broad range of subgroups. The spleen responses were rapid, deep, and sustained, with promising overall survival findings and important evidence of disease modification. These results have the potential to redefine frontline treatment and establish a new treatment paradigm for patients with myelofibrosis."

The CEO and President of Karyopharm, Richard Paulson, then said, "Patients with myelofibrosis have waited too long for meaningful innovation. We are grateful to the FDA for its thoughtful and collaborative engagement in helping define a rigorous path forward. If approved, selinexor in combination with ruxolitinib has the potential to become the first approved combination therapy for patients with myelofibrosis, incorporating a novel class of therapy. We believe this represents a potentially transformative opportunity for patients and a defining moment in Karyopharm's history as we work with urgency toward our planned August sNDA submission."

The sNDA will be based on results from the Phase 3 SENTRY trial comparing selinexor in combination with ruxolitinib against a placebo combination with ruxolitinib, which includes the statistically significant improvement in SVR35 at week 24.

"The SENTRY trial generated a substantial body of evidence showing consistent improvements across multiple measures of clinical activity, including spleen response and a promising signal of overall survival," said Reshma Rangwala, MD, Ph.D., Chief Medical Officer and Head of Research of Karyopharm. "Together, these findings reinforce the biologic rationale for combining XPO1 and JAK inhibition and support the potential of this novel combination to deliver meaningful long-term benefits for patients with myelofibrosis."

Karyopharm is a commercial-stage pharmaceutical company pioneering the science of nuclear export inhibition to develop differentiated therapies for patients with cancer.

Cancer Drug R&D a Necessity

In February 2026, Iqvia discussed the global pharma market projection for 2026, noting that total drug usage is expected to surpass four trillion doses daily by 2030. They wrote, "The largest drivers of medicine spending growth through the next five years will continue to be the use in developed markets of innovative therapeutics, especially in oncology, immunology, diabetes, and obesity."

Pharma sector funding fell between 2024 and 2025, according to a March 26, 2026, article for Fierce Biotech by Nick Paul Taylor.  He wrote that pharma funding had fallen from 2024 but noted that, "2025 was still the third-best year of the past decade. Similarly, overall funding was well above the pre-pandemic norm and only topped by 2020, 2021, and 2024."

The global cancer treatment sector, unfortunately, shows no signs of shrinking. A March 26, 2026, article by Kinjel Shah for Yahoo Finance claimed that cancer incidences were rising. He quoted the American Cancer Society as expecting 2.1 million new cancer cases and over 626,000 cancer-related deaths in 2026. However, technology is ever-evolving to keep up with the disease.

Shah wrote, "Emerging technologies such as genomic sequencing, artificial intelligence, and machine learning are accelerating biomarker discovery, enhancing patient stratification, and enabling earlier and more accurate diagnoses. While a universal cure remains out of reach, consistent improvements in survival rates and patient outcomes across multiple cancer types highlight the tangible benefits of these advances, particularly when combined with earlier detection and intervention."

This innovation comes at a price. In February 2026, Keith Speights wrote an article for The Motley Fool discussing rising care costs, stating that cancer treatments in the U.S. cost roughly US$200 billion in 2020 but are expected to increase to more than US$245 billion by 2030.

BCG talked about trends biopharma companies need to be aware of in 2026 in order to stay competitive, saying, "Near term, companies need to continue to innovate to decrease the complexity and cost of these therapies, and governments can find ways to incentivize and pay for them. The longer-term challenge for companies is to factor operational and economic considerations into R&D decision making earlier, ensuring that trial designs match real-world usage, indication sequences match opportunity, and endpoints enable market access."

Wainwright Lowers Rating and Price Target

Robert Burns of H.C. Wainwright & Co. offered a rating revision for Karyopharm on July 31, 2026, stating that ". . . XPORT-EC-042 primary endpoint miss weighs on Karyopharm's investment case." The drug failed to achieve statistical significance in treating endometrial cancer. The placebo outperformed the drug. Burns wrote: "In our view, this stronger-than-expected placebo performance was the primary driver of the negative outcome. We also believe that a larger mITT population may have increased the likelihood of demonstrating a statistically significant PFS benefit for selinexor in XPORT-EC-042. Karyopharm has indicated that it will complete a comprehensive analysis of the XPORT-EC-042 data and present the full results at a future medical conference."

The company's rating was reduced to "Neutral", and its price target has also been lowered from US$13 to US$3.

Other ratings include:

• On July 31, 2026, Brian Abrahams of RBC Capital reiterated a "Buy" rating but lowered the price target from US$16 to US$8. 
• On the same day, Maury Raycroft of Jeffries reiterated a "Buy" rating but lowered the price target from US$14 to US$11.
• On the same day, Edward Tenthoff of Piper Sandler reiterated a "Buy" rating but lowered the price target from US$16 to US$7.
• Finally, on the same day, Robert Baird of Colleen M. Kusy downgraded the rating to "Hold" but did not offer a price target.

Karyopharm Hopeful for a Quick Review

The press release stated that Karyopharm plans to request Priority Review, which, if granted, could shorten the FDA review period to approximately six months from the agency's acceptance of the application. Long-term follow-up from the SENTRY trial will continue while patients, investigators, and the company remain blinded to treatment assignments.

Ownership & Share Information¹

Karyopharm Therapeutics Inc. has a market cap of US$43.51 million, with 22.66 million shares outstanding. The company's 52-week range is US$1.80-US$10.99. Institutions own 84.70% of shares, while Strategic Investors own 3.46%. Management & Insiders own 1.80% of shares, and the remaining 10.04% of shares are held by Retail.

Frequently Asked Questions

Q: What is an sNDA, and why does it matter?
A: A supplemental New Drug Application (sNDA) is a request to the U.S. Food and Drug Administration (FDA) to approve a new use, dosage, patient population, or labeling change for a drug that is already approved. An approved sNDA can expand a medicine's commercial opportunity and provide patients with additional treatment options without requiring an entirely new drug approval process.

Q: What do Phase 1, Phase 2, and Phase 3 clinical trials mean?
A: Clinical trials are conducted in stages to evaluate whether a new treatment is safe and effective. Phase 1 studies primarily assess safety and dosage in a small group of participants. Phase 2 trials evaluate how well the treatment works while continuing to monitor safety. Phase 3 trials involve much larger patient groups to compare the treatment with existing therapies or a placebo, providing the evidence that regulators such as the U.S. Food and Drug Administration (FDA) use when deciding whether to approve a new medicine.

Q: What is myelofibrosis?
A: Myelofibrosis is a rare type of blood cancer in which scar tissue gradually replaces healthy bone marrow, reducing the body's ability to produce normal blood cells. Common symptoms include anemia, fatigue, enlarged spleen, abdominal discomfort, night sweats, and bone pain. Current treatments help manage symptoms, but there remains a need for therapies that improve long-term outcomes.

Q: What does accelerated FDA approval mean?
A: The FDA's accelerated approval pathway allows certain drugs for serious diseases to reach patients sooner based on surrogate endpoints that are reasonably likely to predict clinical benefit. Companies must later confirm the drug's long-term benefit through additional studies after approval.

Q: What is Priority Review?
A: Priority Review is an FDA designation that shortens the agency's review timeline for certain applications from the standard approximately 10 months to about six months. It is generally reserved for therapies that could provide significant improvements in the treatment, diagnosis, or prevention of serious conditions.