Followers of my blog – Or investors in Reviva Pharmaceuticals (OTC:RVPH) know that the journey of Reviva Pharmaceuticals (OTC: RVPH) has been both positive and negative.

Positive, in the sense that the company has spent more than a decade advancing its drug brilaroxazine through multiple stages of scientific and clinical success, bringing the program to the threshold of a final Phase 3 study.

Negative, in the sense that the share price has been completely demolished. The company now trades with little attention or liquidity on the OTC market, despite owning a late-stage neuropsychiatric asset addressing a huge TAM with a substantial body of clinical evidence behind it.

My choice of words is deliberate.

Schizophrenia itself is generally divided into positive and negative symptoms. Positive symptoms include hallucinations, delusions and disorganized thinking—the symptoms most commonly associated with psychosis. Negative symptoms involve the loss of normal human function: motivation, emotional expression, social connection, speech and the ability to experience pleasure.

Brilaroxazine has shown potential across both symptom domains. But its effect on negative symptoms may ultimately prove to be the more medically significant—and commercially valuable—part of the story.

Positive symptoms may bring someone into the hospital. Negative symptoms can keep that person from returning fully to school, employment, relationships and independent living.

And there is currently no FDA approved medication to treat Negative Symptoms.

That is why brilaroxazine’s apparent effect on these symptoms may be one of the most medically—and commercially—important parts of the Reviva Pharmaceuticals story.

What Are Negative Symptoms?

The word “negative” does not refer to pessimism or hostility. It refers to normal human functions that have been diminished or lost.

The principal issues include:

• Avolition: difficulty initiating purposeful activity
• Anhedonia: reduced ability to anticipate or experience pleasure
• Alogia: diminished speech and verbal expression
• Asociality: reduced interest in relationships
• Blunted affect: diminished outward emotional expression

From the outside, these symptoms can look like laziness, indifference or unwillingness. Clinically, they may reflect a profound impairment in motivation, reward processing, emotional engagement and cognition.

Negative symptoms are strongly associated with poor functional outcomes, diminished quality of life and increased burden on families and healthcare systems. Yet current antipsychotics generally provide limited improvement, particularly for persistent or primary negative symptoms.

Remarkably, the United States still has no medication specifically approved for the treatment of negative symptoms associated with schizophrenia.

Controlling Psychosis Is Not the Same as Restoring Function

Traditional antipsychotics were developed primarily to control dopamine-driven psychosis. Many are effective at reducing hallucinations, delusions and agitation. But their effect on persistent negative symptoms is much less effective.

Some apparent improvement occurs when psychosis, depression or medication side effects improve. A patient who is less paranoid may naturally become more social. A patient who is less sedated may appear more motivated. These are often called secondary negative symptoms.

The hard challenge is treating primary or enduring negative symptoms—the motivational and expressive deficits that remain after acute psychosis has stabilized.

That distinction matters commercially as well as medically. A drug that mainly reduces hallucinations competes in an established market containing numerous branded and generic treatments. A drug that can convincingly improve motivation, social engagement and functioning may occupy a far more differentiated position.

What Brilaroxazine Has Shown

Brilaroxazine is a once-daily serotonin-dopamine signalling modulator being developed by Reviva Pharmaceuticals. Its pharmacology includes activity at dopamine D2, D3 and D4 receptors and serotonin 5-HT1A, 5-HT2A, 5-HT2B and 5-HT7 receptors. Its complicated stuff!

Several of these pathways are implicated in mood, cognition, motivation and negative symptoms. The molecule also has relatively little activity at several off-target receptors associated with metabolic, cardiovascular and gastrointestinal side effects.

In the 411-patient Phase 3 RECOVER trial, the 50 mg dose produced a 10.1-point placebo-adjusted improvement in total Positive and Negative Syndrome Scale, or PANSS, scores over four weeks. The result was statistically significant, with a Cohen’s d effect size of 0.6.

So it looks to be, at this point, highly effective against positive symptoms with little in the way of side effects. BUT – Importantly- the benefit was not limited to positive symptoms.

Compared with placebo, the 50 mg dose produced statistically significant improvement in the PANSS negative-symptom subscale, the PANSS Marder negative-symptom factor, social cognition, general psychopathology, agitation, overall illness severity and Personal and Social Performance.

The onset of benefit appeared relatively early and became progressively stronger over the four-week study.

Now, these were not results from a dedicated trial enrolling patients specifically selected for persistent negative symptoms. RECOVER studied acutely psychotic patients, so some improvement could have occurred indirectly as positive symptoms, depression or disorganization improved.

Nevertheless, the consistency across multiple negative-symptom and functional measures makes the signal difficult to dismiss. For those of you who may know the challenge of treating schizophrenia symptoms, this deserves a ‘wow’!

The One-Year Data Adds an Important Dimension

Negative symptoms are chronic. A four-week result matters, but durability matters more.

Reviva’s 52-week open-label extension enrolled 446 patients with stable schizophrenia and permitted flexible dosing of 15 mg, 30 mg or 50 mg. The study reported continued improvement across positive symptoms, negative symptoms, personal and social functioning and overall illness severity.

At the 50 mg dose, the negative-symptom score improved by approximately 4.4 points at 12 months, compared with 2.8 points at six months. Personal and Social Performance improved by approximately 11.3 points at 12 months.

The extension also reported an overall discontinuation rate of roughly 35%, with most discontinuations attributed to withdrawal of consent or loss to follow-up rather than treatment-related adverse events. Note: This is an exceptional discontinuation rate for this drug class! Long-term treatment was associated with relatively limited changes in weight, lipids, movement-disorder scales and prolactin.

Because the extension was open-label and lacked a placebo comparison, it cannot independently prove long-term efficacy. Stable patients who remain in an extension study may also differ from those who discontinue.

But the data provide something important: the negative-symptom signal did not disappear over time—and may have deepened with continued treatment.

The Vocal Biomarker

One of the most intriguing developments arose from recordings collected during RECOVER psychiatric interviews.

Researchers examined speech latency—the time it took a patient to begin answering a question. Patients with more severe negative symptoms showed substantially longer response delays.

Speech latency was then used to identify a subgroup with more pronounced negative-symptom characteristics. Within this biomarker-positive group, brilaroxazine produced stronger treatment effects across several outcomes, including a larger improvement in the PANSS Marder negative-symptom score than was observed in the overall trial population.

This does not yet make speech latency an approved diagnostic test or validated regulatory endpoint, but it creates several possibilities.

It may help identify patients whose negative symptoms are pronounced enough to demonstrate a treatment effect. It could reduce noise in future studies, improve patient selection and strengthen drug-placebo separation.

In central nervous system drug development, where heterogeneity and placebo response frequently destroy promising trials, better patient selection can be commercially valuable in its own right.

Why Safety Matters to Negative Symptoms

The value of an antipsychotic is not determined by efficacy alone.

Sedation can make a patient appear less motivated. Akathisia and movement disorders can make ordinary activities uncomfortable. Elevated prolactin can produce sexual and hormonal problems. Weight gain and metabolic deterioration can damage physical health, confidence and long-term adherence.

An antipsychotic can therefore improve psychosis while simultaneously interfering with a patient’s ability or willingness to participate in everyday life. This is a major issue with these kind of drugs.

Brilaroxazine’s appeal is not simply that it has shown activity against negative symptoms. It is that the activity has appeared alongside a very favourable looking tolerability profile.

In RECOVER, treatment discontinuation was lower in the 50 mg group than in the placebo group. The company reported low rates of akathisia and extrapyramidal symptoms, limited metabolic changes and no meaningful prolactin elevation.

These findings require confirmation in RECOVER-2 and eventual regulatory review. Cross-trial comparisons must also be treated cautiously.

But a drug that combines negative-symptom efficacy with fewer adverse effects could create a reinforcing advantage: Patients may function better because the drug works—and because they stay on it.

The Commercial Opportunity

The schizophrenia market is already large, and most patients require prolonged or lifelong treatment.

A new antipsychotic entering this market faces a difficult question: why should physicians switch patients from familiar or generic drugs?

Negative-symptom efficacy could provide a compelling answer.

Brilaroxazine could potentially be positioned around three connected attributes:

1. Broad control across positive, negative, mood, cognitive and agitation symptoms
2. A tolerability / safety profile capable of supporting / improving long-term adherence
3. A differentiated role in helping patients regain function rather than merely suppress psychosis

The value assigned to differentiated neuropsychiatric franchises is already substantial.

As I’ve mentioned in previous blogposts, Johnson & Johnson agreed to acquire Intra-Cellular Therapies, the developer of Caplyta, for approximately $14.6 billion. Bristol Myers Squibb acquired Karuna Therapeutics for approximately $14 billion to obtain the schizophrenia treatment that became Cobenfy. Vraylar has grown into a multibillion-dollar annual franchise across schizophrenia, bipolar disorder and major depressive disorder.

These transactions do not mean brilaroxazine is automatically worth billions. Caplyta and Vraylar are approved commercial products, while brilaroxazine remains investigational and still requires another successful Phase 3 trial.

They do demonstrate that a differentiated neuropsychiatric drug with strong intellectual property, label-expansion potential and a tolerable long-term profile can become an unusually valuable pharmaceutical franchise.

A credible negative-symptom claim could increase that value materially because it would give physicians, payers and caregivers a clear reason to choose brilaroxazine over established alternatives.

Patent Runway and Negative Symptoms Are Connected

Reviva has filed a patent application covering a new form of brilaroxazine that it hopes could extend patent protection and commercial exclusivity through 2046. Subject to FDA alignment, the company plans to use the new form in RECOVER-2 and its eventual New Drug Application. The patent has not yet been granted, and FDA acceptance remains a critical requirement.

This is especially relevant to the negative-symptom opportunity. Developing a separate indication requires additional trials, capital and time. A pharmaceutical partner will be reluctant to fund a major negative-symptom program if the drug has only a short commercial runway remaining.

A successful patent reset could provide the time needed to pursue a dedicated negative-symptom trial, additional formulations and indications such as bipolar disorder and major depressive disorder.

The patent strategy therefore does more than protect the original schizophrenia program. It could convert brilaroxazine from a single late-stage asset into a long-term CNS franchise.

What Still Has to Be Proven

The negative-symptom thesis is promising, but incomplete.

RECOVER-2 must reproduce the broad efficacy observed in RECOVER. The negative-symptom effect must remain statistically and clinically meaningful. Reviva must eventually distinguish primary negative-symptom improvement from secondary benefits caused by better control of acute psychosis.

Further, The FDA must accept the new form of brilaroxazine, and meaningful patent protection must actually be granted. Reviva must also finance development without surrendering too much of the asset’s value.

These are substantial risks. But they are increasingly questions of confirmation, trial design, financing and execution. Brilaroxazine has already generated a positive Phase 2 study, a positive Phase 3 study, a one-year safety dataset and a published vocal-biomarker analysis. The data so far is strong and deep.

The Greater Significance

The medical promise of treating negative symptoms is not simply a better score on a psychiatric scale.

It is the possibility that a patient begins initiating activities again. Speaks more readily. Reconnects socially. Experiences pleasure. Participates in treatment. Returns to school or employment. Requires less supervision. Recovers some independence.

Those outcomes matter to patients, families, caregivers, physicians, insurers and healthcare systems.

Commercially, they could transform brilaroxazine from a good entrant in a crowded antipsychotic category into a genuinely differentiated treatment with a defensible role in long-term schizophrenia care.

If brilaroxazine can confirm meaningful improvement in negative symptoms while preserving its favourable safety and tolerability profile, its potential value will be much larger than the market for controlling acute psychosis alone.

And that is a big opportunity.

Disclosure: The Author owns and is acquiring RVPH shares at the date of this blogpost. The Author is not compensated by RVPH and has no relationship with the company except as an investor. This article reflects the Author’s personal opinion and is not investment advice. Readers must conduct their own due diligence and understand that RVPH remains a highly speculative investment.