Early study results from Johnson & Johnson show promising antitumor activity with combination of pasritamig and docetaxel in advanced prostate cancer

Rhea-AI Summary

Johnson & Johnson (NYSE:JNJ) reported preliminary Phase 1b results showing the bispecific T-cell engager pasritamig plus docetaxel produced deep, durable PSA reductions and a safety profile consistent with docetaxel alone. Among 51 patients, PSA declines ≥50% occurred in 64.7% overall and 75.0% of taxane-naïve patients. No cytokine release syndrome or treatment-related deaths were observed. The program is advancing into Phase 3 studies, with two trials ongoing and regulatory designations in China and the U.S.

Positive

• PSA ≥50% in 64.7% of patients overall
• PSA ≥50% in 75.0% of taxane‑naïve patients
• PSA ≥90% in 39.2% overall and 53.6% taxane‑naïve
• No cytokine release syndrome and no treatment‑related deaths
• Program advancing to Phase 3 with two ongoing registrational trials
• Breakthrough Therapy designation in China and Fast Track from FDA

Negative

• Grade ≥3 TRAEs attributed to docetaxel in 29.4% of patients
• Common TRAEs include fatigue (60.8%) and alopecia (41.2%)
• Pasritamig‑related fatigue in 33.3% and non‑chronic diarrhea in 11.8%

News Market Reaction – JNJ

-0.69%

1 alert

-0.69% News Effect

On the day this news was published, JNJ declined 0.69%, reflecting a mild negative market reaction.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

Patients treated: 51 patients Median prior therapies: 3 prior therapies (range 1–9) PSA ≥50% response: 64.7% overall +5 more

8 metrics

Patients treated 51 patients Phase 1b pasritamig plus docetaxel in mCRPC as of Dec 9, 2025

Median prior therapies 3 prior therapies (range 1–9) Pretreated metastatic castration-resistant prostate cancer population

PSA ≥50% response 64.7% overall Patients achieving ≥50% PSA reduction on pasritamig plus docetaxel

PSA ≥50% taxane-naïve 75.0% of taxane-naïve Taxane-naïve subgroup PSA reductions ≥50%

PSA ≥90% response 39.2% overall Patients achieving ≥90% PSA reduction on combination regimen

PSA ≥90% taxane-naïve 53.6% of taxane-naïve Deep PSA responses ≥90% in taxane-naïve subgroup

Bone-only PSA ≥50% / ≥90% 88.2% / 76.5% Taxane-naïve, bone-only disease subgroup PSA reductions

Grade ≥3 TRAEs 29.4% docetaxel vs 2% pasritamig Treatment-related adverse events in Phase 1b study

Market Reality Check

Price: $248.43 Vol: Volume 7,608,168 is below...

normal vol

$248.43 Last Close

Volume Volume 7,608,168 is below the 20-day average of 9,369,125, suggesting no outsized reaction. normal

Technical Price 245.17 is trading above the 200-day MA at 186.96, reflecting a longer-term uptrend into this news.

Peers on Argus

JNJ slipped 0.45% with below-average volume while large-cap pharma peers like AB...

JNJ slipped 0.45% with below-average volume while large-cap pharma peers like ABBV, AZN, LLY, and NVS also posted small declines and NVO gained modestly, pointing to mostly stock-specific trading rather than a coordinated sector move.

Common Catalyst Only one key peer, LLY, reported separate trial data in type 2 diabetes, indicating today’s prostate cancer update for JNJ is not part of a shared catalyst across the group.

Historical Context

5 past events · Latest: Feb 24 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Feb 24	Regulatory submission	Positive	-0.5%	sBLA filed for IMAAVY in warm autoimmune hemolytic anemia based on positive Phase 2/3 data.
Feb 21	Clinical data update	Positive	+1.4%	TREMFYA QUASAR LTE showed durable 3‑year remission and no new safety issues in ulcerative colitis.
Feb 19	Clinical trial results	Positive	-1.8%	RYBREVANT FASPRO plus pembrolizumab produced a 56% ORR in first‑line recurrent/metastatic HNSCC.
Feb 18	Capex expansion	Positive	+0.7%	Announced >$1 billion investment in next‑gen cell therapy manufacturing facility in Pennsylvania.
Feb 18	FDA designation	Positive	+0.7%	RYBREVANT FASPRO received FDA Breakthrough Therapy Designation in advanced head and neck cancer.

Pattern Detected

Recent positive R&D and regulatory updates have produced a mix of aligned and contrary price moves, with modestly more alignment than divergence.

Recent Company History

Over the past weeks, JNJ has issued several positive catalysts, including an sBLA submission for IMAAVY in wAIHA on Feb 24, Breakthrough Therapy Designation for RYBREVANT FASPRO on Feb 18, and long‑term TREMFYA ulcerative colitis data on Feb 21. It also announced a >$1 billion U.S. cell therapy manufacturing investment. Market reactions have been mixed, with some R&D wins coinciding with gains and others with modest declines, framing today’s prostate cancer Phase 1b results within a steady flow of innovation news.

Regulatory & Risk Context

Active S-3 Shelf

Shelf Active

Active S-3 Shelf Registration 2026-02-11

An effective S-3ASR shelf, filed on 2026-02-11, allows JNJ to issue unsecured debt securities over time under an existing indenture, with terms set in future prospectus supplements and proceeds earmarked for general corporate purposes including working capital, capex, buybacks, refinancing, and acquisitions.

Market Pulse Summary

This announcement presents early but compelling Phase 1b data for pasritamig plus docetaxel in metas...

Analysis

This announcement presents early but compelling Phase 1b data for pasritamig plus docetaxel in metastatic castration-resistant prostate cancer, with high rates of deep PSA responses and a safety profile consistent with docetaxel. Two Phase 3 trials and additional combination studies are already in progress, indicating a clear development path. Investors may track upcoming Phase 3 readouts, regulatory interactions, and how this KLK2-targeted T‑cell engager fits alongside JNJ’s recent stream of oncology and immunology updates.

Key Terms

bispecific T-cell engaging antibody, metastatic castration-resistant prostate cancer, prostate-specific antigen, cd3, +4 more

8 terms

bispecific T-cell engaging antibody medical

"pasritamig (JNJ-78278343), a first-in-class bispecific T-cell engaging antibody, in combination"

A bispecific T‑cell engaging antibody is a laboratory-made protein that can bind simultaneously to a cancer or diseased cell and to a T cell, the immune system’s attack cell, effectively bringing them together so the T cell can kill the target. Investors care because this approach can dramatically amplify a drug’s potency and market potential but also carries high trial, safety and manufacturing risks—similar to a powerful new weapon that must be handled precisely.

metastatic castration-resistant prostate cancer medical

"in patients with metastatic castration-resistant prostate cancer. The combination demonstrated"

An advanced form of prostate cancer that has spread beyond the prostate to other parts of the body (metastatic) and no longer responds to treatments that lower male hormones designed to starve the tumor (castration-resistant). It matters to investors because it defines a high unmet medical need with limited treatment options, so clinical trial results, new drug approvals, or safety setbacks can sharply change the valuation and prospects of companies working in this area; think of it as a weed that has spread and become resistant to the usual weedkiller.

prostate-specific antigen medical

"including high rates of prostate-specific antigen (PSA) responses and sustained PSA reductions"

A protein made by the prostate that is measured in a blood test to help detect and monitor prostate conditions, including cancer and benign enlargement. Think of it as a dashboard gauge for prostate health: changes in the level can influence demand for diagnostics, treatments, and screenings, so shifts in how the test is used or interpreted, or news about therapies tied to it, can affect companies and investor expectations.

cd3 medical

"mechanism of action, binding CD3 on T cells and human kallikrein 2 (KLK2)."

CD3 is a group of proteins on the surface of T cells, the immune system’s front-line soldiers, that act like a control panel to turn those cells on and off. It matters to investors because many modern therapies work by engaging or blocking CD3 to direct T cells against cancer or dampen harmful immune reactions; success, safety and regulatory approval of CD3-targeting drugs can significantly affect a biotech company’s prospects.

kallikrein 2 (klk2) medical

"binding CD3 on T cells and human kallikrein 2 (KLK2). KLK2 is a novel, highly specific"

Kallikrein 2 (KLK2) is a protein enzyme produced mainly in the prostate that helps break down other proteins and can be released into the blood. It matters to investors because KLK2 can serve as a biological marker or drug target: changes in its levels or therapies aimed at it can affect diagnostic tests, clinical trial readouts, regulatory outcomes and potential revenue streams for companies working on prostate-related diagnostics and treatments — think of it like a thermometer that helps gauge disease activity or a lock that a drug might fit.

cytokine release syndrome medical

"No patients experienced cytokine release syndrome of any grade or treatment-related deaths."

An intense immune overreaction in which the body's defense system releases a large surge of signaling proteins, causing fever, low blood pressure, breathing trouble or organ stress; imagine the immune system's alarm going into overdrive and flooding the body with emergency responders. Investors care because this side effect can slow or block regulatory approval, increase clinical trial costs and liabilities, limit how widely a therapy can be used, and therefore affect a drug's market value and sales potential.

Breakthrough Therapy Designation regulatory

"Pasritamig monotherapy has received Breakthrough Therapy Designation in China and Fast Track"

A breakthrough therapy designation is a regulatory fast-track given to a drug or treatment that shows early signs of providing a major improvement over existing options for a serious condition. Think of it as a VIP lane that can speed up development and more intensive guidance from regulators, which matters to investors because it can shorten time to market, reduce development risk and potentially increase a company’s value — though it does not guarantee approval.

Fast Track designation regulatory

"Designation in China and Fast Track designation from the U.S. Food and Drug Administration"

A "fast track designation" is a process that speeds up the review and approval of a product or project, allowing it to reach the market or be completed more quickly than usual. For investors, it can signal that a product may become available sooner, potentially leading to earlier revenue or benefits, and indicating a priority status that might influence company performance and market opportunities.

AI-generated analysis. Not financial advice.

Combination demonstrates deep PSA responses and favorable safety profile with plans to advance into Phase 3

Data highlight the potential of this first-in-class next-generation T-cell engager to expand the role of immunotherapy in prostate cancer

RARITAN, N.J., Feb. 26, 2026 /PRNewswire/ -- Johnson & Johnson (NYSE:JNJ) today announced preliminary results from a Phase 1b study evaluating pasritamig (JNJ-78278343), a first-in-class bispecific T-cell engaging antibody, in combination with docetaxel in patients with metastatic castration-resistant prostate cancer. The combination demonstrated a safety profile consistent with docetaxel alone, with no new or unexpected safety signals observed. The regimen also showed clinically meaningful efficacy, including high rates of prostate-specific antigen (PSA) responses and sustained PSA reductions, supporting continued development and advancement into Phase 3 studies. The results were presented for the first time at the 2026 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium (Abstract #171).¹

Pasritamig is designed to engage the immune system through a novel mechanism of action, binding CD3 on T cells and human kallikrein 2 (KLK2). KLK2 is a novel, highly specific prostate cancer target with minimal expression outside prostate tissue. By both activating and directing T cells to KLK2-expressing tumor cells, pasritamig enables targeted immune engagement. This differentiated, prostate-specific approach was intentionally built to focus immune activity on prostate cancer cells, which may help limit effects on healthy tissue, and supports administration in a doctor's office rather than hospital setting.

"These data represent an important step forward for patients with advanced prostate cancer," said Professor Shahneen Sandhu,* M.D., Ph.D., MBBS, FRACP, Associate Professor, Consultant Medical Oncologist and researcher at Peter MacCallum Cancer Centre, and study investigator. "In a disease where outcomes remain poor for many patients, seeing encouraging clinical activity alongside a favorable safety profile in combination with docetaxel reinforces the potential of this approach and supports further clinical development."

"Based on these findings, we are increasingly confident in the potential of pasritamig to meaningfully improve outcomes for people with prostate cancer," said Charles Drake, M.D., Ph.D., Vice President, Prostate Cancer and Cross Cancer Immuno-Oncology, Johnson & Johnson. "The ability to combine pasritamig with docetaxel, where prior approaches in the field have fallen short, gives us a strong foundation for Phase 3 development. What we're seeing with this combination, including deep and durable PSA responses, underscores the promise of this combination immunotherapy approach and our commitment to advancing innovation that can make a difference for patients."

Detailed Study Results

In the study, pasritamig was evaluated in combination with docetaxel in an outpatient setting in patients with metastatic castration-resistant prostate cancer whose disease had progressed following androgen receptor pathway inhibitor therapy. Approximately half of the patients (45 percent) had received at least one prior taxane-based regimen. The primary endpoint was safety and identification of the recommended regimen for further development in Phase 2/3 studies, with secondary and exploratory endpoints assessing clinical activity, including PSA response rates.¹

As of December 9, 2025, 51 patients had received pasritamig plus docetaxel, including patients who were pretreated with a median of three prior therapies (range, 1-9). Reductions of 50 percent or greater in PSA levels were achieved in 64.7 percent of patients overall and in 75.0 percent of taxane-naïve patients. Reductions of 90 percent or greater in PSA levels were achieved in 39.2 percent of patients overall and 53.6 percent of taxane-naïve patients. Among taxane-naïve patients with bone-only disease, confirmed PSA reductions of 50 percent or greater and 90 percent or greater were observed in 88.2 percent and 76.5 percent of patients, respectively. Patients were able to continue pasritamig beyond docetaxel discontinuation. Those patients received a median of six docetaxel doses every three weeks and eight pasritamig doses every six weeks, supporting the potential for sustained disease control over time.¹

The safety profile of pasritamig plus docetaxel was consistent with the known safety profile of docetaxel in metastatic castration-resistant prostate cancer. The most common treatment-related adverse events (TRAEs) occurring in at least 20 percent of patients included fatigue (60.8 percent), alopecia (41.2 percent), diarrhea and nausea (31.4 percent each), peripheral edema (27.5 percent), peripheral sensory neuropathy (25.5 percent) and dysgeusia (23.5 percent). Pasritamig-related adverse events occurring in at least 10 percent of patients were fatigue (33.3 percent) and non-chronic diarrhea (11.8 percent). Grade 3 or higher TRAEs attributed to docetaxel were observed in 29.4 percent of patients, compared with only two percent attributed to pasritamig. No patients experienced cytokine release syndrome of any grade or treatment-related deaths.¹

Two ongoing Phase 3 studies are evaluating pasritamig in the metastatic castration-resistant prostate cancer setting. KLK2-comPAS (NCT07164443) is evaluating pasritamig as monotherapy, and KLK2-PASenger (NCT07225946) is evaluating pasritamig in combination with docetaxel.^2,3 Beyond these Phase 3 studies, pasritamig is also being evaluated in earlier-phase combination studies. Pasritamig monotherapy has received Breakthrough Therapy Designation in China and Fast Track designation from the U.S. Food and Drug Administration, supporting its continued clinical development.

About the Study

The Phase 1b study (NCT05818683) is an open-label trial evaluating the safety and clinical activity of pasritamig in combination with docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC) whose disease has progressed following treatment with an androgen receptor pathway inhibitor. The primary objective is to determine the recommended regimen for further development based on safety, with secondary and exploratory endpoints assessing clinical activity. Pasritamig was administered intravenously every six weeks, with initial step-up doses given during the first treatment cycle, in combination with docetaxel administered intravenously every three weeks. Treatment was delivered in an outpatient setting. Corticosteroids were used only as standard premedication for docetaxel, and hematopoietic growth factor support was permitted as needed.⁴

About Pasritamig (JNJ-78278343)

Pasritamig (JNJ-78278343) is an investigational T-cell-redirecting bispecific antibody (bsAb) targeting human kallikrein 2 (KLK2) on prostate cancer cells and CD3 receptor complexes on T cells, leveraging the body's immune system to selectively target and eliminate cancer cells. This innovative approach is being evaluated in pretreated patients with metastatic castration-resistant prostate cancer (mCRPC), a patient population with limited treatment options.

About Metastatic Castration-Resistant Prostate Cancer (mCRPC)

Metastatic castration-resistant prostate cancer (mCRPC) is a challenging and aggressive stage of prostate cancer where the disease progresses despite androgen deprivation therapy.⁵ Patients often experience metastasis to bones and lymph nodes, leading to poor outcomes and limited treatment options, including chemotherapy and second-line hormone therapies.⁶ The median overall survival ranges from 13.5 to 31.6 months depending on the site of metastasis, with a typical range of 15 to 36 months across the broader population.^7,8 Survival rates can vary significantly depending on factors such as prior treatment history, disease burden, and response to therapy. The need for more effective treatments is critical, as the disease continues to impact a large number of men globally, with metastatic castration-resistant prostate cancer (mCRPC) being responsible for a substantial number of prostate cancer-related deaths.

About Johnson & Johnson

At Johnson & Johnson, we believe health is everything. Our strength in healthcare innovation empowers us to build a world where complex diseases are prevented, treated, and cured, where treatments are smarter and less invasive, and solutions are personal. Through our expertise in Innovative Medicine and MedTech, we are uniquely positioned to innovate across the full spectrum of healthcare solutions today to deliver the breakthroughs of tomorrow and profoundly impact health for humanity. Learn more at https://www.jnj.com/ or at www.innovativemedicine.jnj.com. Follow us at @JNJInnovMed.

Cautions Concerning Forward-Looking Statements

This press release contains "forward-looking statements" as defined in the Private Securities Litigation Reform Act of 1995 regarding product development and the potential benefits and treatment impact of pasritamig (JNJ-78278343). The reader is cautioned not to rely on these forward-looking statements. These statements are based on current expectations of future events. If underlying assumptions prove inaccurate or known or unknown risks or uncertainties materialize, actual results could vary materially from the expectations and projections of Johnson & Johnson. Risks and uncertainties include, but are not limited to: challenges and uncertainties inherent in product research and development, including the uncertainty of clinical success and of obtaining regulatory approvals; uncertainty of commercial success; manufacturing difficulties and delays; competition, including technological advances, new products and patents attained by competitors; challenges to patents; product efficacy or safety concerns resulting in product recalls or regulatory action; changes in behavior and spending patterns of purchasers of health care products and services; changes to applicable laws and regulations, including global health care reforms; and trends toward health care cost containment. A further list and descriptions of these risks, uncertainties and other factors can be found in Johnson & Johnson's most recent Annual Report on Form 10-K, including in the sections captioned "Cautionary Note Regarding Forward-Looking Statements" and "Item 1A. Risk Factors," and in Johnson & Johnson's subsequent Quarterly Reports on Form 10-Q and other filings with the Securities and Exchange Commission. Copies of these filings are available online at www.sec.gov, www.jnj.com or on request from Johnson & Johnson. Johnson & Johnson does not undertake to update any forward-looking statement as a result of new information or future events or developments.

*Professor Shahneen Sandhu, M.D., Ph.D., MBBS, FRACP has provided consulting, advisory, and speaking services to Johnson & Johnson; she has not been paid for any media work.

Source: Johnson & Johnson

______________________

1 Patel MR, et al. Safety and Efficacy of Pasritamig (PAS) + Docetaxel (DOCE) in Participants with Metastatic Castration-Resistant Prostate Cancer (mCRPC): Initial Results of a Phase 1b Study. Presented at: 2026 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium; February 26, 2026; San Francisco, California.

2 ClinicalTrials.gov. A Study of Pasritamig Versus Placebo in Late Line Metastatic Castration-resistant Prostate Cancer (mCRPC) (KLK2-comPAS). https://clinicaltrials.gov/study/NCT07164443. Accessed February 2026.

3 ClinicalTrials.gov. A Study of Pasritamig With Docetaxel Versus Docetaxel in Participants With Metastatic Castration-Resistant Prostate Cancer (KLK2-PASenger). https://clinicaltrials.gov/study/NCT07225946. Accessed February 2026.

4 ClinicalTrials.gov. A Study of JNJ-78278343 in Combination With Either JNJ-63723283 (Cetrelimab), Taxane Chemotherapy, or Androgen Receptor Pathway Inhibitors for Metastatic Prostate Cancer. https://www.clinicaltrials.gov/study/NCT05818683. Accessed February 2026.

5 Kushwaha PP, Gupta S. New insights for drug resistance in metastatic castration-resistant prostate cancer. Cancer Drug Resist. 2022;5(3):846-849. Published 2022 Aug 2. doi:10.20517/cdr.2022.83

6 Wallace K, Landsteiner A, Bunner S, Engel-Nitz N, Luckenbaugh A. Epidemiology and mortality of metastatic castration-resistant prostate cancer (mCRPC) in a managed care population in the United States. J Clin Oncol. 2020;38(15_suppl):e13592. doi:10.1200/JCO.2020.38.15_suppl.e13592

7 Wallace KL, Landsteiner A, Bunner SH, Engel-Nitz NM, Luckenbaugh AN. Increasing prevalence of metastatic castration-resistant prostate cancer in a managed care population in the United States. Cancer Causes Control. 2021;32(12):1365-1374. doi:10.1007/s10552-021-01484-4

8 Kawahara T, Saigusa Y, Yoneyama S, et al. Development and validation of a survival nomogram and calculator for male patients with metastatic castration-resistant prostate cancer treated with abiraterone acetate and/or enzalutamide. BMC Cancer. 2023;23:214. doi:10.1186/s12885-023-10700-0

 

Media contact: Oncology Media Relations oncology_media_relations@its.jnj.com	Investor contact: Jessica Margevich investor-relations@its.jnj.com
	U.S. Medical Inquiries
	+1 800 526-7736

View original content to download multimedia:https://www.prnewswire.com/news-releases/early-study-results-from-johnson--johnson-show-promising-antitumor-activity-with-combination-of-pasritamig-and-docetaxel-in-advanced-prostate-cancer-302698631.html

SOURCE Johnson & Johnson

FAQ

What did Johnson & Johnson (JNJ) report about pasritamig plus docetaxel on Feb 26, 2026?

They reported preliminary Phase 1b results showing deep PSA reductions and a docetaxel‑consistent safety profile. According to the company, 51 patients yielded PSA ≥50% in 64.7% overall and no cytokine release syndrome was observed.

How effective was pasritamig (JNJ‑78278343) with docetaxel in taxane‑naïve prostate cancer patients?

Taxane‑naïve patients showed high PSA responses: 75.0% had ≥50% PSA reductions. According to the company, taxane‑naïve bone‑only patients had confirmed PSA ≥50% in 88.2% and ≥90% in 76.5%.

What safety results did JNJ report for pasritamig combined with docetaxel in Feb 2026?

The safety profile was consistent with docetaxel, with no new safety signals and no treatment‑related deaths. According to the company, Grade ≥3 TRAEs attributed to pasritamig were 2%, while docetaxel‑attributed Grade ≥3 TRAEs were 29.4%.

Will Johnson & Johnson advance pasritamig to Phase 3 trials after the Feb 26, 2026 results?

Yes, the program is advancing into Phase 3 development with two ongoing registrational trials. According to the company, KLK2‑comPAS and KLK2‑PASenger are evaluating monotherapy and combination with docetaxel respectively.

What regulatory designations does pasritamig have as of Feb 26, 2026?

Pasritamig has received Breakthrough Therapy designation in China and Fast Track designation from the U.S. FDA. According to the company, these designations support continued clinical development and regulatory engagement.

How durable was treatment with pasritamig plus docetaxel in the reported study?

Patients received a median of six docetaxel doses and continued pasritamig, receiving a median of eight pasritamig doses. According to the company, this supports potential sustained disease control over time.