New Drug Zoci Shrank Tumors in 4 of 10 Patients With a Hard-to-Treat Neuroendocrine Cancer

The symptoms were easy to explain away at first.

A stomach that felt full after a few bites. Heartburn that would not quit. A dull ache in the belly that came and went. Tiredness that sleep did not fix.

For many people, those turn out to be ordinary problems. But sometimes they are the first quiet signs of a rare and fast-moving cancer — one that often is not found until it has already spread.

That cancer is called extrapulmonary neuroendocrine carcinoma. It is a mouthful, so most people shorten it to epNEC. It starts outside the lungs, often in the digestive tract or pancreas, and it grows quickly. The first treatment is usually platinum-based chemotherapy. When that stops working, doctors have no standard next step to offer. The chemo regimens used after that help only a little, and for only a short time.

That is why a set of results presented this week drew attention.

On Friday, November 6, 2026, researchers shared updated results at the NANETS 2026 symposium in Las Vegas — the largest North American meeting focused on neuroendocrine cancers. A new targeted drug called zoci (zocilurtatug pelitecan) shrank tumors in 40% of patients whose epNEC had already grown through platinum chemotherapy. The responses lasted a median of 5.6 months, and fewer than 1 in 100 patients had to stop the drug because of side effects.

This is early research, and this post will be careful about what it does and does not prove. But for a group of patients who currently hear "there is no standard treatment left," a 4-in-10 response rate is real news.

It is also timely news. Tuesday, November 10 is NET Cancer Day, the annual day that raises awareness of neuroendocrine cancers — cancers that hide behind common symptoms, and that too often are found late.

What Is Extrapulmonary Neuroendocrine Carcinoma?

Neuroendocrine cells are a special kind of cell found all over the body. They act like a bridge between the nervous system and the hormone system. They receive signals and respond by releasing hormones and other messengers.

When these cells turn cancerous, doctors group the cancers into two broad families:

• Neuroendocrine tumors (NETs) — usually slower-growing and more organized under the microscope.
• Neuroendocrine carcinomas (NECs) — poorly organized, fast-growing, and much more aggressive.

The word "extrapulmonary" simply means "outside the lungs." So epNEC is a neuroendocrine carcinoma that starts somewhere other than the lung — most often in the stomach, intestines, colon, or pancreas (often grouped as GEP-NEC, for gastroenteropancreatic NEC), but also in places like the prostate, bladder, and cervix.

A few things make epNEC especially hard:

• It grows fast. These cancers can double and spread in weeks to months, not years.
• It is usually found late. The early symptoms — fullness, indigestion, pain, weight loss — look like everyday problems.
• It behaves like small cell lung cancer. Even though it starts elsewhere, epNEC shares biology with that aggressive lung cancer, which is why platinum chemotherapy, a small cell lung cancer staple, is the usual first treatment.
• Options run out quickly. After platinum chemo stops working, there is no established standard of care.

A Neuroendocrine Carcinoma Is Not Just a "Worse" Neuroendocrine Tumor

Here is the most common mix-up with this disease — and it matters, because the two cancers are treated very differently.

A NET and an NEC can start in the very same organ. A person can have a neuroendocrine tumor of the pancreas, and another person can have a neuroendocrine carcinoma of the pancreas. The names sound like close cousins. The behavior is not close at all.

Think of it like two vehicles with similar names. One is a delivery van on a set route, moving at a steady, modest speed. The other is the same van with the brakes cut and the accelerator stuck down. Same family name on the side — completely different problem on the road.

In practice, that difference shows up like this:

• A typical NET may grow slowly enough that doctors watch it, or treat it with hormone-blocking drugs, targeted pills, or radiation-based therapies over years.
• An NEC usually needs chemotherapy right away, because waiting even a few weeks can mean real growth.

The shared word "neuroendocrine" describes where these cancers come from — not how they behave. Grade and type decide the treatment, not the family name.

This is also why awareness days like NET Cancer Day carry a simple message for all neuroendocrine cancers: these diseases hide behind common symptoms. If you do not suspect them, you cannot detect them. Persistent indigestion, flushing, diarrhea, unexplained weight loss, or pain that keeps coming back deserves a real workup — especially when standard treatments for the "obvious" cause are not helping.

How Does Zoci Work?

Zoci is a type of drug called an antibody-drug conjugate, or ADC. ADCs are sometimes described as "smart bombs" or "guided missiles" of cancer treatment, and the comparison is a fair one.

A Delivery Truck With an Address

An ADC has three parts:

• The antibody — a protein built to find and stick to one specific marker on the surface of a cancer cell.
• The payload — a powerful chemotherapy drug carried along for the ride. In zoci, the payload is called pelitecan.
• The linker — the connector that holds the payload until the antibody reaches its target.

Zoci's antibody looks for a marker called DLL3. DLL3 sits on the surface of small cell lung cancer cells and neuroendocrine carcinoma cells — including epNEC — in large amounts. On healthy adult tissue, it is barely there. That gap is the whole point: the drug can deliver its chemo mostly where the DLL3 "address" is posted, and spare most healthy cells.

When the antibody locks onto DLL3, the cancer cell pulls the drug inside, the payload is released, and the chemotherapy does its work from within the cell.

The Dose Used in the Study

In this trial, zoci was given on its own (not combined with other drugs):

• 1.6 mg/kg of body weight
• By IV infusion
• Once every 3 weeks

One more detail from the data is worth knowing: the drug shrank tumors across the full range of DLL3 levels, including in patients whose tumors showed low or even no detectable DLL3. That is unusual for a targeted drug, and it may mean patients would not need a biomarker test to qualify — though this needs confirming in larger studies.

Why a New Option Matters So Much Here

To understand why a 40% response rate made news, it helps to understand what usually happens after platinum chemotherapy fails in epNEC.

Doctors fall back on second-line chemo regimens borrowed from other cancers. These regimens do shrink tumors for some patients, but responses are uncommon and usually brief — especially in GEP-NEC, the digestive-tract group, where outcomes are the poorest. A large European study of advanced high-grade digestive neuroendocrine cancers, cited in this week's report, confirms how tough those numbers are.

So patients face a hard reality:

• The cancer is fast.
• The standard toolbox is nearly empty.
• Clinical trials are often the best option — but not every patient lives near a center running one.

For a cancer with no standard second-line treatment, an early trial result is not just a statistic. It is a possible next door to walk through.

What Did the New Study Find?

The results come from a Phase 1b/2 clinical trial (officially listed as NCT06885281). The updated data were presented at the NANETS 2026 symposium on November 6, 2026, by Dr. Amr Mohamed of UH Seidman Cancer Center and Case Western Reserve University.

The basics:

• Who was studied: people with advanced or metastatic epNEC whose cancer had progressed during or after platinum-based chemotherapy.
• Main group measured for benefit: 60 patients.
• Larger group measured for safety: 133 patients treated in the study overall.
• Treatment: zoci alone, 1.6 mg/kg IV every 3 weeks.
• How benefit was measured: scans checked by the study investigators using standard tumor-measurement rules (called RECIST).
• Important limit: this was a single-arm study. Everyone got zoci. There was no comparison group getting another drug or standard care.

Finding #1: 4 in 10 Patients Had Their Tumors Shrink

The confirmed response rate was 40.0% — 24 of the 60 patients in the main group had tumors shrink enough to count as a response.

To picture that: line up 10 people whose cancer had already grown through their first chemotherapy. For 4 of them, scans on this drug showed their tumors meaningfully smaller. In a cancer where second-line chemo responses are uncommon, that stands out.

Another 15% had their cancer hold steady, bringing the disease control rate to 55.0% (33 of 60 patients) — meaning more than half had tumors shrink or at least stop growing for a time.

Finding #2: It Worked in Both Major Subtypes

The benefit was not limited to one corner of this disease:

• GEP-NEC (digestive tract and pancreas): response rate 35.9% (14 of 39 patients).
• Other epNECs (such as prostate, bladder, and other sites): response rate 47.6% (10 of 21 patients).

These subgroups are small, so the exact percentages come with wide margins of error. But responses in both groups suggest the drug's effect is not a fluke of one subtype.

Finding #3: Responses Lasted a Median of 5.6 Months

Shrinking is only half the story. How long does it last?

The median duration of response was 5.6 months. In plain terms, among patients whose tumors shrank, half kept that benefit for at least about 5 to 6 months.

And among 18 responders who had been followed long enough to judge, 6 — one in three — were still responding, or had a response last 6 months or longer.

For a fast-moving cancer, months of control can mean real life: a holiday season, a family event, time to plan. It is not a cure, and this post will not pretend otherwise. But it is time.

Finding #4: Side Effects Were Manageable for Most Patients

Among all 133 patients treated:

• 12.8% had a severe (grade 3 or higher) side effect judged related to the drug.
• The most common severe effects were anemia (low red blood cells, 5.3%) and neutropenia (low white blood cells, 3.8%).
• Lung inflammation (called ILD or pneumonitis) appeared in 2 patients (1.5%), both moderate, with no severe cases.
• Only 1 of 133 patients (0.8%) stopped the drug because of a treatment-related side effect.
• There were no treatment-related deaths.

Fewer than 1 in 100 patients stopping treatment because of side effects is a striking figure for a chemotherapy-carrying drug — and staying on treatment matters, because a drug can only help while a patient can take it.

Finding #5: Benefit Did Not Depend on High DLL3 Levels

Because zoci targets DLL3, the natural guess would be "more DLL3, more benefit." The early data did not work out that way. Tumors shrank across high, low, and even undetectable DLL3 levels.

If that holds up, it removes a common barrier: patients may not need a special test result to be candidates. Larger studies will need to confirm it.

Living With Treatment: The Supportive-Care Side

A response rate is a scan result. Daily life on treatment is something else — and it is where supportive care earns its place.

Zoci's most common severe side effects involved the blood counts. That sounds abstract until you translate it:

• Anemia (low red blood cells) can mean deep fatigue, shortness of breath on stairs, and a racing heart doing simple tasks.
• Neutropenia (low white blood cells) raises the risk of infection. A fever that would be minor for someone else can be an emergency during treatment.

A few habits carry real weight during cycles of a drug like this:

• Report a fever of 100.4°F (38°C) or higher right away. Do not wait until morning. This is the single most important rule when white counts may be low.
• Keep up fluids and electrolytes. Treatment days, poor appetite, diarrhea, or vomiting can quietly drain fluid and salts like potassium and magnesium. Steady hydration — small, frequent drinks rather than large amounts at once — helps many patients stay out of the urgent care chair between cycles.
• Eat small and often. Fast-growing cancers and their treatments both raise the body's energy needs while shrinking appetite. Small, protein-containing meals and snacks are easier to manage than three large meals.
• Speak up about new cough or breathlessness. Lung inflammation was rare in this study (1.5%, both cases moderate), but it is the side effect where early reporting changes outcomes most.
• Track fatigue honestly. If climbing stairs or showering becomes hard, that is medical information, not a personal failing. Tell the team.

The goal of supportive care is not just comfort. It is keeping you strong enough to stay on the treatment that is working.

What Should Patients and Caregivers Watch For?

Call the care team promptly — the same day — for any of these:

• Fever of 100.4°F (38°C) or higher, or chills and shaking
• A new or worsening cough, or shortness of breath
• Unusual bruising, bleeding, or tiny red spots on the skin
• Extreme tiredness that is new or suddenly worse
• Vomiting or diarrhea that keeps fluids from staying down
• Not urinating much, dark urine, or dizziness when standing
• Rapid weight loss — more than a few pounds in a week without trying
• Confusion or unusual sleepiness
• Pain that is new, or pain that suddenly gets worse

Questions to Ask the Oncology Team

1. Is my cancer a neuroendocrine carcinoma or a neuroendocrine tumor — and how does that change my treatment plan?
2. My cancer grew after platinum chemotherapy. What options do I have now, and is a clinical trial one of them?
3. Have you heard of zoci (zocilurtatug pelitecan)? Is there a trial site I could reach?
4. Would I need my tumor tested for DLL3, or does the early data suggest it may not matter?
5. If I join a trial of an antibody-drug conjugate, how often are visits and infusions?
6. How will my blood counts be monitored, and what number should trigger a call?
7. What is the plan if I develop a fever between cycles?
8. Should I be watching for lung symptoms, and which ones matter most?
9. How do we protect my nutrition and hydration during treatment?
10. If this treatment works, how long might the benefit last — and what would we try next?

Why This News Matters

Three things make this more than a one-day headline.

First, the FDA has already given zoci special designations — Orphan Drug Designation for neuroendocrine carcinomas (August 2026) and Fast Track status for epNEC. Those do not approve a drug, but they signal that regulators recognize both the rarity of this cancer and the lack of options.

Second, the company says it will pursue an accelerated approval pathway, based on the FDA's feedback, using the single-arm trial's response data. Accelerated approval is a real route for cancers like this, where waiting years for a giant randomized trial would leave patients with nothing. Topline results from the full study population are expected in 2027, and a global Phase 3 trial — testing zoci as maintenance treatment earlier in the disease — is planned to start next year.

Third, the timing carries a message. These data were presented days before NET Cancer Day (November 10). Neuroendocrine cancers spend years being mistaken for irritable bowel syndrome, menopause, anxiety, or simple indigestion. Every advance like this one is also an argument for suspecting the disease sooner.

The Bottom Line

For patients with extrapulmonary neuroendocrine carcinoma whose cancer has grown through platinum chemotherapy, there is currently no standard treatment to turn to. In an early, single-arm trial, a new DLL3-targeted drug called zoci offered something real:

• 40.0% of patients had tumors shrink (24 of 60).
• 55.0% had tumors shrink or hold steady.
• Responses lasted a median of 5.6 months; a third of responders with enough follow-up reached 6 months or more.
• Severe drug-related side effects occurred in 12.8%, and only 0.8% stopped treatment because of them.

Now the careful part. This does not mean zoci is proven to help people live longer — there is no survival data yet, and no comparison group. It does not mean the drug is available at your cancer center — it is investigational and not FDA-approved. And a 40% response rate means 60% of patients did not respond.

What it does mean: for one of the most option-poor cancers in oncology, a targeted drug is producing meaningful, durable shrinkage with side effects most patients could stay on treatment through. That is exactly the kind of result that deserves a larger trial — and, if the 2027 data hold up, possibly an approval.

If you or someone you love is facing this diagnosis, the most useful step is a conversation: ask whether a trial fits, ask about DLL3, and ask early — because with a cancer this fast, timing is part of treatment.

Frequently Asked Questions

What is extrapulmonary neuroendocrine carcinoma (epNEC)?

It is a rare, fast-growing cancer of neuroendocrine cells that starts outside the lungs — most often in the digestive tract or pancreas. It behaves similarly to small cell lung cancer and is usually treated first with platinum-based chemotherapy.

How is epNEC different from a neuroendocrine tumor (NET)?

NETs are usually slower-growing and better organized; NECs are aggressive and spread quickly. They can start in the same organ but are treated very differently, which is why knowing your exact type matters.

What is zoci?

Zoci (zocilurtatug pelitecan) is an investigational antibody-drug conjugate. It uses an antibody to find a marker called DLL3 on cancer cells and deliver a chemotherapy payload directly inside them. It is given by IV once every 3 weeks.

How well did zoci work in the study?

In the main group of 60 patients whose cancer had progressed after platinum chemotherapy, 40.0% had their tumors shrink, and 55.0% had shrinkage or stable disease. Responses lasted a median of 5.6 months.

What were the side effects?

The most common severe side effects were anemia (5.3%) and neutropenia (3.8%). Lung inflammation occurred in 1.5% of patients, both moderate. Only 0.8% of patients stopped the drug due to a treatment-related side effect, and there were no treatment-related deaths.

Is zoci FDA-approved?

No. Zoci is investigational. It has received FDA Orphan Drug Designation and Fast Track designation for this disease, and the maker plans to pursue an accelerated approval pathway, with fuller data expected in 2027.

Do I need a DLL3 test to get zoci?

In this study, tumors shrank across all DLL3 levels, including low or undetectable. That suggests a test may not be required, but larger studies need to confirm it. Trial eligibility rules vary, so ask the trial team.

Can I get zoci now?

Only through a clinical trial, if you qualify. Ask your oncologist about trials for previously treated neuroendocrine carcinoma, or search ClinicalTrials.gov for NCT06885281 and related studies.

Why is there no comparison group in this study?

Early-phase trials often give everyone the study drug to learn whether it works at all and what doses are safe. Because there was no comparison group, we cannot yet say zoci is better than other options or that it extends life — only that tumors shrank in a meaningful share of patients.

When might zoci become more widely available?

The company expects topline data from the full study population in 2027 and plans a Phase 3 trial starting next year. If the data support it, an accelerated approval request could follow — but timelines can change.

Sources

1. Zai Lab (via Business Wire). "Zai Lab Presents Updated Clinical Data Demonstrating Zocilurtatug Pelitecan (Zoci) Induces Clinically Meaningful Responses and a Manageable Safety Profile in Previously Treated Extrapulmonary Neuroendocrine Carcinomas," published November 5, 2026; updated data presented at the NANETS 2026 symposium, November 6, 2026.
2. ClinicalTrials.gov. "A Study of ZL-1310 in Participants With Selected Solid Tumors," trial NCT06885281.

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For more information on how HuMOLYTE can support your gut health during chemotherapy, visit our product page or consult your health care provider.

This blog was reviewed by Dr. Sourabh Kharait.

This blog post is for educational purposes only and is not intended as medical advice. Always consult with your healthcare provider before making changes to your treatment plan, hydration strategies, or diet. The information provided is based on general insights and may not apply to individual circumstances.