The treatment landscape for spinal muscular atrophy, a rare disease causing progressive muscular weakness, has shifted dramatically over the last decade. A drug from Scholar Rock called apitegromab could add to that progress if the FDA approves it by a Sept. 22 deadline. 

Since 2016, U.S. regulators have approved a gene-targeting medicine from Biogen, a gene therapy from Novartis and an oral treatment from Roche. All three can change SMA’s course and help babies survive and hit growth milestones they otherwise wouldn’t. All three therapies have “mixed” effects on motor function, however, resulting in eventual decline that a muscle-preserving therapy might help to address, Piper Sandler analysts wrote in a report last year.

Scholar Rock believes it has that therapy in apitegromab, which blocks a protein called myostatin that can limit muscle growth. Phase 3 testing showed apitegromab together with standard therapy significantly improved motor function after one year versus typical care and a placebo. The result vaulted Scholar Rock’s market value into the billions of dollars and made it an acquisition target. 

Since then, Scholar Rock has been gearing up to launch apitegromab. The company switched up its management team, naming industry veteran David Hallal its CEO and ex-Alnylam Pharmaceuticals president Akshay Vaishnaw its R&D chief. It’s built up a commercial team. On a conference call in June, Hallal noted how its leaders want to “build and scale” the company “into the next great global biotech powerhouse.”

Scholar Rock is betting so heavily on its path that it’s sticking to rare diseases despite encouraging study results in obesity, one of the most lucrative markets in drug research. — Ben Fidler

Sanofi spent nearly $4 billion on Prinicipia Biopharma five years ago in large part because of a drug now known as tolebrutinib. That investment could pay dividends on Sept. 28, when the FDA is scheduled to decide whether to clear it for a form of multiple sclerosis. 

Tolebrutinib is one of a newer class of oral medications called BTK inhibitors designed to treat autoimmune diseases rather than cancer. Study results to date haven’t met initial expectations, however, and development has been slowed by safety concerns. Testing was previously halted due to signs of liver toxicity and Sanofi abandoned testing in myasthenia gravis. 

Tolebrutinib, as well as another, similar drug from Merck KGaA, also failed multiple trials in people with the common, “relapsing” form of multiple sclerosis.

However, Sanofi did report success in a less prevalent form of the disease known as non-relapsing secondary progressive MS, or nrSPMS. People with that form of the condition accumulate disabilities over time instead of experiencing periodic disease flares. Notably, they don’t have any approved treatments available to them. 

Success in nrSPMS could allow Sanofi to make something of tolebrutinib, even if the drug’s sales potential is lower than the company once envisioned. 

In a research report in May, Leerink Partners analyst Faisal Khurshid noted how the liver toxicity seen in testing of tolebrutinib is likely to yield a strict safety warning from the FDA. Despite that potential restriction, consensus estimates have tolebrutinib generating nearly $1.6 billion in sales at its peak, assuming approval. — Ben Fidler

Note: The FDA has extended its review of Blenrep and now intends to make a decision on Oct. 23, 2025.

GSK made history when U.S. regulators approved Blenrep in 2020. The drug was the first marketed multiple myeloma medicine to target BCMA, a protein that’s universally found on malignant cells.

Several, more effective BCMA-targeting therapies quickly followed Blenrep to market, however, and GSK’s drug, which is associated with eye toxicity, struggled. The company withdrew it from market in 2022 after it failed a confirmatory trial. 

GSK has since found a way to revive Blenrep. The company continued testing Blenrep in earlier lines of care and alongside other standard myeloma drugs, rather than as monotherapy. In a pair of studies, it outperformed two widely used medicines, Darzalex and Velcade, on measures of disease progression. The findings prompted GSK to begin seeking new approvals.

Blenrep has already been cleared for a relaunch in the U.K. A return to the U.S. markets could follow if the FDA approves it by a July 23 deadline. While Blenrep will face even stronger competition now than before, doctors are also better able to manage Blenrep’s side effects through dose reductions and eye drops, which could help expand use. — Jonathan Gardner

Note: The FDA rejected deramiocel for Duchenne muscular dystrophy on July 11, 2025. Capricor intends to resubmit its approval application. Read our coverage here.

Cardiomyopathy, a type of progressive weakening of the heart muscle, is the leading cause of death in people with Duchenne muscular dystrophy. The symptom isn’t specifically addressed by available therapies, either.

Capricor Therapeutics aims to change that with a cell therapy the FDA could approve by Aug. 31. Yet leadership turmoil at the regulator appears to hang over what already wasn’t a clear-cut case.

Capricor’s therapy, deramiocel, is derived from a special type of heart cell known to help preserve function. The company evaluated it in a Phase 2 trial, which showed treatment improved measures of upper limb function and the heart’s ability to pump blood. However, the results came from only 20 participants — eight of whom received therapy. 

To add further support to its case, Capricor has also marshalled data from a historical study of heart function in Duchenne patients. 

The FDA accepted Capricor’s approval application in March. Since then, though, multiple top officials have been forced out of the FDA office that regulates gene therapies. Vinay Prasad — who has long been critical of Sarepta Therapeutics’ Elevidys, another Duchenne medicine with imperfect data — is now that office’s leader. 

Initially, the agency scheduled an advisory committee meeting to help it review Capricor’s application. But it later canceled its request — a step Stat News reported last month was taken because Prasad was “skeptical of the treatment.” In a June note to clients, Leerink Partners’ Mani Foroohar added how there’s been talk that Prasad and Nicole Verdun, a high-ranking gene therapy regulator placed on leave by the FDA, “disagreed over the regulation” of deramiocel.

In a June 24 statement, Capricor CEO Linda Marban said “all regulatory milestones have proceeded as expected” without major issues. An in-person meeting with FDA staff is scheduled for late July, roughly a month before a final verdict is expected. — Ben Fidler

Note: The FDA approved donidalorsen as Dawnzera on Aug. 21, 2025. Read our coverage here. 

Ionis Therapeutics started 2025 on a new footing. The biotech, which for years has regularly out-licensed the drug candidates it developed, had set a course to become a commercial-stage company of its own. The FDA’s Dec. 19 approval of its rare disease drug Tryngolza kick-started the company’s plans. 

Ionis could add a second, wholly-owned drug to its sales shelf if the FDA grants approval to donidalorsen by a decision deadline of Aug. 21. 

Marketing a drug is a challenge in its own right. But should Ionis succeed with donidalorsen, the company will enter a competitive market that’s set for further disruption as new kinds of therapies advance.

The drug is designed to prevent the recurrent swelling attacks experienced by people with hereditary angioedema. Multiple preventive options are already available, as are on-demand treatments. In June, the FDA approved a new drug, CSL’s Andembry, and continues to review another from Kalvista Pharmaceuticals, although the agency notably missed its decision deadline.

Further out, Intellia Therapeutics is advancing a gene editing therapy it sees as a potential one-time option that could allow patients to do without regular preventive treatment.

Ionis will have to carve out a place in the market for donidalorsen if it secures an OK as expected. Polling the company commissioned suggests it could make a strong case to patients: Two-third of patients contacted by the Harris Poll said they felt they hadn’t yet found the best preventive option for them. — Ned Pagliarulo

Note: The FDA missed its initial approval decision deadline for sebetralstat, but cleared the drug as Ekterly on July 7, 2025. Read our coverage here. 

People with hereditary angioedema, a rare condition estimated to affect one in every 10,000 to 50,000 people globally, have multiple medicines that can treat or prevent the disease’s hallmark swelling attacks. But all are limited in some way, leaving room for new options. One that could emerge this quarter, if the FDA approves a drug from Kalvista Therapeutics by a June 17 deadline.

Kalvista’s drug, sebetralstat, is meant to be an oral alternative to the injectable medicines, like Takeda’s Firazyr, that are typically used to treat swelling episodes. While effective, injectable medicines can require multiple shots to work. In a survey of HAE physicians Leerink Partners analysts conducted last year, a majority of respondents cited convenience, route of administration and the lack of an oral option as the “major shortcomings” of available therapies. 

In testing, Kalvista’s drug proved it could provide comparable symptom relief to injectable medicines. Yet the company has faced persistent questions about the need for its therapy. In a December report, Leerink analysts noted how some investors believe on-demand HAE drugs like sebetralstat may be “getting squeezed” by the onslaught of available and emerging preventive options. Generic versions of Firazyr are now available, too, complicating Kalvista’s pitch to insurers.

Yet Stifel analysts also cautioned that there has “consistently been a disconnect” between investors and clinicians on the topic, and that skeptics may be underestimating Kalvista’s opportunity. They expect sebetralstat to generate $600 million in annual U.S. sales at its peak. — Ben Fidler

Note: The FDA approved lenacapavir as Yeztugo on June 18, 2025. Read our coverage here.

Despite efforts to grow oncology sales, Gilead’s core business continues to be HIV, where a portfolio of approved medicines brings in the bulk of its revenue. The company could add another sales driver to its mix by June 19 if the FDA expands the use of lenacapavir, a twice-yearly injectable medicine it currently sells as Sunlenca.  

Since 2022, lenacapavir has been available in the U.S. for people whose HIV infections can’t be controlled by existing treatments due to drug resistance, intolerance or safety concerns. 

But two large studies last year showed a twice-yearly formulation of the drug could be powerfully effective in preventing infections, too. In one trial comparing the therapy to the once-daily pill Truvada and background HIV infection rates, there were zero infections reported in the group receiving lenacapavir — results so striking the study was stopped early. In the other, infections were reduced by 96% compared to background rates and 89% more effective than Truvada.  

The combined evidence could allow Gilead to bring forward a more convenient, preventive option to a market dominated by oral medications. The anticipated launch is “likely a pivotal point” for the so-called pre-exposure prophylactic, or PrEP market, “and arguably the most anticipated [Gilead] milestone of the year,” wrote Mizuho Securities analyst Salim Syed, in February. 

Gilead has multiple other HIV medicines in testing, too, among them a once-yearly version of lenacapavir it’s moving from Phase 1 directly into a late-stage trial. — Delilah Alvarado

Note: The FDA approved clesrovimab as Enflonsia on June 9, 2025. Read our coverage here.

The past few years have brought new medicines and vaccines for respiratory syncytial virus. By June 10, Merck & Co. hopes to add a new option in the form of an antibody drug dubbed clesrovimab.  

Like Sanofi and AstraZeneca’s Beyfortus, clesrovimab offers a way to protect infants from RSV-related disease. While Beyfortus and another, more limited-use antibody drug, Synagis, are cleared for use in newborns — and Pfizer’s vaccine Abrysvo can be used for maternal immunization — the need for additional treatments remains significant. RSV remains the leading cause of hospitalizations among infants and demand for Beyfortus, which was first approved in July 2023, was so high during its first year on the market that its makers struggled to produce enough. The drug quickly became a blockbuster, with sales reaching $1.8 billion in 2024. 

Merck aims to claim a share of that market with clesrovimab. In testing, the drug displayed a “competitive, but not meaningfully differentiated profile” from Beyfortus, leading to investor questions about its commercial potential, Leerink Partners analyst David Risinger wrote in January. 

One advantage Merck will lean on is accessibility, as clesrovimab is administered as a single shot regardless of an infant’s weight, while Beyfortus comes in different doses and requires two injections. That, plus the “strength of [Merck’s] underlying pediatric vaccine contracts,” could help the company make inroads against Beyfortus, Risinger wrote. — Delilah Alvarado

Note: The FDA approved Nucala for chronic obstructive pulmonary disease on May 22, 2025.

Last September, the FDA made Sanofi and Regeneron Pharmaceuticals’ Dupixent the first biologic therapy approved for chronic obstructive pulmonary disease. Its introduction added a new type of treatment to the inhaled medications and steroids long used to manage the inflammatory disease. 

Biologic competition could be coming soon for Dupixent, should the FDA also grant an approval to GSK’s Nucala by its deadline of May 7. As Sanofi and Regeneron did with Dupixent, GSK is aiming for an indication that covers people who have an “eosinophilic” form of COPD. People with this type of the disease, which refers to a kind of white blood cell, are at increased risk of flare-ups and deterioration in lung function.

Testing of Nucala in COPD has taken many years. The main trial supporting GSK’s application — called Matinee — builds on two Phase 3 studies GSK completed in 2017. Data from Matinee showed that treatment, when added to inhaled maintenance therapy, significantly reduced the annualized rate of moderate or severe exacerbations versus placebo.

Dupixent may prove hard to challenge, though a full comparison between the drugs will have to wait until GSK presents detailed Matinee data at a future scientific meeting. Elsewhere, Amgen and AstraZeneca are also testing their biologic drug Tezspire in COPD, too. — Ned Pagliarulo

Note: The FDA approved pz-cel as Zevaskyn on April 29, 2025. Read our coverage here.

Epidermolysis bullosa is a rare disease that makes the skin fragile and susceptible to frequent blistering. Historically, it has been managed only with supportive care, as no drugs were approved. But treatments are finally emerging. In 2024, the FDA approved a topical gene therapy from Krystal Biotech. By April 29, Abeona Therapeutics could follow with a cell-based alternative. 

Abeona’s medicine — a one-time treatment made from a person’s skin cells — helped heal wounds and reduce pain in people with the disease during clinical testing. 

Yet the therapy, prademagene zamikeracel, or pz-cel, was rejected by U.S. regulators last April over questions related to the drug’s manufacturing. The complete response letter Abeona received was one of several production-related regulatory setbacks gene and cell therapy developers have hit in recent years. Abeona’s share price still hasn’t recovered since pz-cel’s application was turned back.

The company addressed the agency’s concerns in a matter of months and resubmitted its filing in October. The FDA quickly accepted the submission and chose to skip convening a panel of advisers, which analysts took as a positive sign for Abeona’s approval prospects. Abeona, for its part, has begun launch preparations in anticipation of treating its first patient in the third quarter. 

A positive decision is crucial for the financial future of Abeona. The company hopes to break even next year, and an approval could yield from the FDA a special voucher it can sell to other drugmakers. But pz-cel will compete with Krystal’s gene therapy, Vyjuvek, which is administered weekly through a topical gel rather than via a long-lasting skin graft and has gotten off to a strong sales start.

Investors are skeptical of Abeona’s prospects as a result. But the two therapies may be “more complementary than competitive,” as Vyjuvek likely isn’t a “one-size-fits-all” treatment, Stifel analysts wrote last year. — Ben Fidler

Note: The FDA approved fitusiran as Qfitlia on March 28, 2025. Read our coverage here. 

By late March, an experimental hemophilia drug called fitusiran will finally get its day at the FDA, potentially concluding a long and winding development path.

Originally discovered by Alnylam, fitusiran is an RNA-based medicine that suppresses production of antithrombin, a protein that stops blood from clotting. A once-monthly shot, the drug could help people with either the A or B forms of hemophilia to reduce their dependence on the factor replacement therapies they use to prevent bleeds, regardless of whether they’ve developed an immune response, or “inhibitors,” to those treatments.

Sanofi has been involved with the program for a decade, acquiring some rights in 2014 and then gaining full ownership four years later. Over that time, fitusiran has overcome multiple obstacles. Clinical testing was twice suspended due to blood-clotting incidents, one of which resulted in the death of a study participant. Sanofi adjusted and tested lower doses and fitusiran eventually succeeded in trials. But the delays pushed fitusiran’s approval filing until 2024; Sanofi had previously anticipated a submission three years earlier.

In the meantime, other therapies for hemophilia A and B have been approved, including Sanofi’s own Altuviiio, Roche’s Hemlibra and a few gene therapies. These treatments offer patients more dosing flexibility and longer-lasting effects, raising the bar for new entrants.

In a presentation to investors last year, Sanofi left fitusiran off of a list of anticipated future blockbuster medicines. — Delilah Alvarado

Note: The FDA approved diazoxide choline as Vykat XR on March 26, 2025. Read our coverage here. 

Prader-Willi syndrome, a rare condition that causes insatiable hunger known as hyperphagia, has been difficult for drugmakers to target. Multiple high-profile programs have failed in clinical testing or been rejected by regulators, leaving the estimated 10,000 to 20,000 people in the U.S. who have the condition without any treatments to curb their relentless desire to eat. But the wait could soon end if the FDA approves Soleno Therapeutics’ diazoxide choline, or DCCR, by a March 27 deadline.

Soleno is making an unorthodox pitch to the FDA. Its drug — an extended-release form of a molecule, diazoxide, that’s used to treat low blood sugar — failed its main goal in a Phase 3 trial four years ago. Soleno claimed the results were skewed by the COVID-19 pandemic, arguing that data collected before and after March 1, 2020 differed vastly and that DCCR showed consistent benefits on secondary measures.

Discussions with regulators yielded an unusual plan to prove that case: A new portion was added to the study in which patients were randomized to either continue or stop receiving DCCR, and tested for hyperphagia levels over time. Soleno claimed success in that evaluation in Sept. 2023, leading to an approval application and a stock surge that lifted its market value past $2 billion.

The FDA delayed a decision in November, fueling skepticism among investors about Soleno’s chances. Yet some Wall Street analysts remain optimistic. In a note last year, Dae Gon Ha, of Stifel, noted how there is a “need of a ‘win’” for Prader-Willi patients and the agency’s willingness to be flexible in rare diseases. DCCR also hit statistical significance in a study the FDA endorsed and received a so-called Breakthrough Therapy designation from afterwards, indicating that “at face value, the data supports a meaningful effect,” wrote Baird analyst Brian Skorney in November. — Ben Fidler

Note: The FDA approved vutrisiran for transthyretin amyloidosis with cardiomyopathy on March 20, 2025. Read our full coverage here. 

Alnylam Pharmaceuticals has developed five approved drugs in a track record of success that has cemented its as one of the industry’s most valuable companies. It still isn’t consistently profitable, however. An upcoming FDA decision on a drug called vutrisiran may finally change that. 

Alnylam already sells vutrisiran, as well as a predecessor drug called Onpattro, for a form of the genetic disease transthyretin amyloidosis that affects nerves. For years, though, Alnylam has been trying to expand use of those therapies to people whose disease causes heart damage, or cardiomyopathy. The reward could be significant: Global Market Insights estimated earlier this year that the market for transthyretin amyloidosis treatments will surpass $11 billion by 2032, with the “cardiomyopathy” form accounting for the bulk of sales.

Alnylam came close with Onpattro, only to see the FDA reject its application in 2023. The company is hoping for a better outcome with vutrisiran, which, unlike Onpattro, was tested for long enough to tell whether it could extend lives and prevent hospital stays. Alnylam used a special voucher to speed up the FDA’s review, too. A decision is expected by March 23. 

Yet it’s unclear whether the FDA will convene experts beforehand to discuss Alnylam’s application — a concern of investors given the company changed its statistical analysis plan before reporting success, Leerink Partners analyst Mani Foroohar wrote in November. Even if vutrisiran is approved, its commercial prospects are uncertain, as Alnylam will have to compete with Pfizer and BridgeBio Pharma without clear evidence its drug is best. — Ben Fidler

Note: The FDA approved GSK’s vaccine as Penmenvy on Feb. 18, 2025. Read our full coverage here. 

GSK could soon answer Pfizer in the two pharmaceutical companies’ ongoing market battle to develop better meningitis vaccines.

By Feb. 14, the FDA will decide whether to approve a shot dubbed MenABCWY. The vaccine combines components of two marketed inoculations, Bexsero and Menveo, to protect against the five most common strains of bacterial meningitis, an infection that in severe cases can cause deadly brain swelling.

If approved, the shot will represent another attempt to boost vaccine uptake against meningococcal disease, which remains low due to a complex vaccine schedule.

MenABCWY would also compete against rival Pfizer's Penbraya, a similar five-in-one shot that received FDA approval in 2023 for people between the ages of 10 and 25. GSK’s vaccine was tested in a similar age group.

Approval would also extend GSK and Pfizer’s rivalry in infectious disease. The companies have fought for market share with earlier meningitis shots and, more recently, with dueling RSV vaccines. But both have been challenged by dips in vaccine sales that have impacted earnings. — Delilah Alvarado

Note: The FDA approved suzetrigine as Journavx on Jan. 30, 2025. Read our full coverage here. 

The opioid epidemic has killed hundreds of thousands of people in the U.S.. By the end of January, the FDA could approve a new, non-addictive pain drug experts hope will become a life-saving alternative for many.

Vertex Pharmaceuticals has spent decades in the incredibly challenging field of pain research. After much trial and error, the Boston-based biotechnology company finally found a drug it believed worked well enough to make it through clinical testing and FDA review. Several mid- to late-stage studies have shown this medication can alleviate different forms of pain, from the acute kind seen after certain surgeries to the chronic kind experienced by people with diabetes.

Importantly, though, the drug has yet to prove more effective than opioids. That, combined with opioids being cheap and widely reimbursed by insurers, raises questions about its ultimate value. Doctors say they aren't entirely sure what pain the drug will be the best suited to treat or how open payers will be to covering it.

That uncertainty has crept over to Wall Street as well. Vertex lost $15 billion in market value in December, when a study evaluating its drug against a type of lower back pain produced results that investors found lackluster. Many equity analysts still think Vertex has a blockbuster product on its hands, but there is at least one who argues the sales forecasts are overblown. — Jacob Bell