Executive Summary: Key Legal and Evidentiary Issues

• Central issue was whether the asthma/COPD drug Symbicort is capable, as a matter of general causation, of causing EGPA (Eosinophilic Granulomatosis with Polyangiitis) in ordinary use.
• Plaintiff’s failure-to-warn product liability claim depended on proving, through admissible expert evidence, that Symbicort can cause EGPA, which he was unable to do.
• The defence’s expert evidence, accepted as impartial and reliable, established only an association between Symbicort and EGPA, not a biological or scientific causal link.
• The plaintiff, acting without expert support and relying largely on his personal experience and selected literature excerpts, failed to meet the evidentiary threshold for general causation on a summary judgment motion.
• The court held that mere adverse event reports and regulatory label changes indicating an association do not amount to proof of causation in negligence or product liability.
• Summary judgment was found to be a fair, proportionate, and efficient procedural vehicle to resolve the discrete gating issue of general causation and to dismiss the action without a trial.

Background and parties

The case of Listovets v. AstraZeneca Canada Inc. arises from a product liability and negligence claim brought by the plaintiff, Vladislav Listovets, against AstraZeneca, the manufacturer of the prescription inhaler Symbicort. Mr. Listovets, a former physics professor who later worked as a financial planner, was diagnosed with chronic obstructive pulmonary disease (COPD) at age 62, in 2003. His respirologist prescribed Symbicort, a combination inhaler containing budesonide (a corticosteroid) and formoterol (a bronchodilator), to treat his respiratory symptoms. Symbicort had been authorized for sale in Canada for asthma since 2002 and later for COPD in 2009. At the time he started the medication, the Symbicort product monograph warned of several rare but serious side effects, including increased wheezing, hypersensitivity reactions, allergic reactions and cardiac rhythm abnormalities, but it did not mention EGPA. In 2016, at age 75, Mr. Listovets was diagnosed with EGPA, a rare vasculitic disease involving inflammation of blood vessels, elevated eosinophil counts, and multi-organ involvement. Treatment for EGPA commonly includes corticosteroids, and in his case his rheumatologist prescribed oral Prednisone and advised him to continue using Symbicort. After his diagnosis, Mr. Listovets learned that AstraZeneca had updated the Symbicort monograph in 2015 to refer to certain eosinophilic conditions and clinical features consistent with Churg–Strauss syndrome (another name for EGPA). Disturbed by the timing of the label change and his own diagnosis, he came to believe that Symbicort had caused or contributed to his EGPA.

Allegations and litigation history

In May 2018, acting as a self-represented litigant, Mr. Listovets commenced an action against AstraZeneca seeking approximately $2.7 million in damages for negligence. His core theory was that AstraZeneca knew, or ought to have known, that Symbicort could cause EGPA, that it failed to warn patients and physicians about this serious risk from the time Symbicort was first marketed, and that it concealed this risk until compelled by Health Canada to change the label in 2015. Over the years that followed, the case was case-managed by the Superior Court. The plaintiff consistently expressed a desire for an expeditious resolution and at one point indicated his intention to bring a summary judgment motion in his favour. In early 2025, AstraZeneca sought to bring its own motion for summary judgment focused solely on the discrete issue of general causation—whether Symbicort is capable of causing EGPA in ordinary use. In mid-2025, the court directed that AstraZeneca’s motion on general causation proceed first, treating it as a “neat, gating issue” that could potentially dispose of the action or significantly narrow what remained for trial. Both parties understood that if the plaintiff could not establish general causation, the negligence and failure-to-warn claim could not succeed. Conversely, if he did succeed on this point, further issues would be left to be dealt with later.

Evidence and expert testimony

On the summary judgment motion, AstraZeneca relied on affidavit evidence and the expert report of Dr. Parameswaran Nair, a respirologist and academic at McMaster University. Dr. Nair was proffered as an expert on EGPA, its suspected causes, and any relationship with Symbicort or similar inhaled corticosteroids. The plaintiff cross-examined both the company representative and Dr. Nair, but did not file any expert report of his own. Instead, he relied on his own affidavit, his medical history, and excerpts from various medical or scientific publications. The court first dealt with the admissibility and impartiality of the defence expert. While the plaintiff argued that Dr. Nair was “extremely partial” and conflicted—principally because he held the AstraZeneca Chair in Respiratory Diseases and because AstraZeneca had other institutional ties to McMaster—the judge applied the Supreme Court of Canada’s framework in White Burgess. The court held that the key question was not merely whether the relationship might look problematic to an outside observer, but whether there was evidence that the expert was unable or unwilling to discharge his overriding duty to the court to provide fair, objective and non-partisan assistance. Having accepted and sworn to that duty, and in the absence of concrete evidence of bias or dishonesty, Dr. Nair was found to meet the basic threshold of admissibility. Any alleged slant in his interpretation of the plaintiff’s medical records went to the weight of his evidence, not its admissibility. On the merits of causation, Dr. Nair’s opinion was clear. He acknowledged that there is an observed association between inhaled corticosteroids (including Symbicort) and EGPA, but he emphasized that association is not the same as causation. In his view, there was no scientific evidence in the literature or in his own research establishing that Symbicort can cause EGPA or vasculitis. He offered a biological explanation for the observed association: Symbicort is prescribed for asthma, which can in fact be the earliest stage of EGPA, so patients may be on Symbicort before EGPA manifests; and in some patients transitioning from high-dose oral corticosteroids to lower-dose inhaled corticosteroids, reduction of systemic steroids can “unmask” underlying EGPA that had been suppressed, rather than the inhaled drug causing the disease. He also found no biologically plausible mechanism by which the relatively modest inhaled steroid dose in Symbicort could cause harm when a much higher oral steroid dose (Prednisone) was used to treat the same condition. The plaintiff, by contrast, relied on his personal experience, on adverse event reports showing a relatively small number of EGPA cases reported worldwide in Symbicort users, and on selected clinical reports or studies. The judge held that these materials were not admissible or sufficient as expert causation evidence: the plaintiff was not qualified to interpret them as an expert, the articles were not filed in full, authors were not available for cross-examination, some involved different drugs or single-patient reports, and one study was in Portuguese without translation. Without a qualified expert supporting a causal link, the plaintiff was left without admissible proof of general causation.

Legal framework: negligence, product liability and summary judgment

The court then situated the dispute in the standard negligence framework. A negligence claim requires proof of a duty of care, breach of the applicable standard of care, compensable damage, factual (“but for”) causation, and legal remoteness. In pharmaceutical product liability, manufacturers owe a duty to warn of inherent dangers in the ordinary use of their products that are known or ought reasonably to be known. In failure-to-warn claims, the first analytical step is general causation: is the product defective in its ordinary use or does it have a propensity to injure in a way that can cause the harm alleged? If this “can it cause” question is not met, the claim fails regardless of foreseeability or the adequacy of warnings. The judge emphasized that, in practice, expert evidence is almost always required to prove both standard of care and causation in such medically complex cases. Without a qualified expert linking the drug to the alleged harm, a plaintiff faces an insurmountable evidentiary hurdle. On procedure, the court applied the summary judgment principles from Hryniak and subsequent Ontario Court of Appeal decisions. The goal was to determine whether there was any genuine issue requiring a trial. Where the evidentiary record allows the judge to make the necessary factual findings, apply the law, and reach a fair result efficiently and proportionately, summary judgment is appropriate. Both sides had put their “best foot forward” on the general causation issue, and there was no suggestion that fuller evidence would be available at a trial.

Symbicort monograph, regulatory language and adverse event reports

A key plank of the plaintiff’s argument was the 2015 change to the Symbicort product monograph, which inserted a warning under “Eosinophilic Conditions.” This warned that, in rare cases, patients on inhaled corticosteroids might present with systemic eosinophilic conditions and clinical features consistent with Churg–Strauss syndrome, noting that such events often occurred when oral steroid doses were reduced after introduction of an inhaled corticosteroid. The monograph expressly stated that a causal relationship between inhaled corticosteroids and these conditions had not been established. The plaintiff argued that this amounted to an admission of causation and that AstraZeneca had previously concealed this information. The court rejected that interpretation. The evidence from AstraZeneca and Dr. Nair was that Health Canada had proposed this language to harmonize with other similar products, and AstraZeneca adopted it as a “regulatory imposition.” On a plain reading, the language signalled only a temporal association and expressly disclaimed any established causal link. Regulatory cautionary wording grounded in association and pharmacovigilance did not equate to proof that the drug could cause EGPA. The plaintiff also relied on AstraZeneca’s count of 47 global adverse event reports of EGPA involving Symbicort over more than two decades, including a handful before the label change. The court again distinguished between association and causation: an adverse event report records that an event occurred after exposure to a drug, but does not, without more, prove that the drug caused the event. In the absence of expert analysis and scientific consensus establishing general causation, such reports were insufficient to ground liability.

Assessment of the plaintiff’s arguments and evidence

The judgment carefully addressed each of the plaintiff’s substantive contentions. His suggestion that AstraZeneca was driving overprescription of Symbicort 200, including by supplying free samples to physicians, did not advance the causation question. Even if marketing practices led to wider usage, that would not demonstrate that Symbicort can cause EGPA. His reliance on clinical case reports and small studies was undermined by admissibility and relevance problems, and by the lack of independent expert testimony to interpret them. The court further noted that, according to both Dr. Nair and one of the plaintiff’s own treating respirologists, Symbicort is actually used to treat asthma symptoms in patients with EGPA, which is consistent with its therapeutic rather than harmful role. Taken together, the evidentiary record showed at most that asthma and EGPA often coexist, that EGPA may emerge when systemic steroids are tapered, and that Symbicort use can precede or accompany EGPA diagnosis. It did not show, on a balance of probabilities, that Symbicort is capable of causing EGPA.

Outcome on liability and causation

Ultimately, the court concluded that the plaintiff had not met the burden of proving general causation, the foundational element of his failure-to-warn claim. Without admissible expert evidence demonstrating that Symbicort can cause EGPA in its ordinary use, there was no genuine issue requiring a trial on causation or on any downstream issues such as breach of the duty to warn or damages. The motion judge emphasized that while the plaintiff sincerely believed that Symbicort had harmed him and was understandably searching for an explanation for his serious illness, the court was bound by the rules of evidence and the governing legal tests. The sad reality, in the judge’s view, was that the plaintiff likely developed EGPA as part of the natural progression of his underlying disease, and his respiratory problems that prompted Symbicort use were probably early symptoms of EGPA rather than its cause. A failure to warn that does not result in proven harm is not actionable negligence, and without causation there could be no liability. The court therefore granted AstraZeneca’s motion for summary judgment and dismissed all of the plaintiff’s claims in the amended statement of claim.

Costs and final disposition

After resolving liability, the court turned to costs. Applying the usual Ontario principles, costs follow the event and are intended to provide fair and proportionate indemnity to the successful party. AstraZeneca’s actual legal fees exceeded $250,000, and its disbursements—primarily related to retaining Dr. Nair—were approximately $15,600. Nonetheless, AstraZeneca sought only $10,000 in fees plus its disbursements, citing the plaintiff’s age and health as reasons to moderate the request. The plaintiff argued there should be no costs order, accusing AstraZeneca of delay, but the court found that the defendant had cooperated in bringing the matter to a merits-based resolution. In the end, the court fixed costs at $25,000 inclusive of disbursements as an amount that was reasonable, fair and proportionate in the circumstances, noting that this figure represented less than five percent of AstraZeneca’s actual fees in defending a multi-million-dollar claim. The formal result was that AstraZeneca, as the successful party, obtained dismissal of the action in its entirety and a monetary order for $25,000 in costs against Mr. Listovets.