--- title: "Merck KGaA's $1.3B Iron Bet Ends Bloodletting, Not Besremi" url: https://drugnews.com.tw/articles/2026-10-24-merck-kgaa-silence-divesiran-polycythemia-vera-besremi-en.html date: 2026-10-24 lang: en category: "商業分析系列" tags: ["polycythemia vera","phlebotomy","Merck KGaA","divesiran","PharmaEssentia Besremi"] summary: "PV patients still get blood drawn every few weeks. On Oct 19 Merck KGaA bid $1.3B for divesiran: 88% phlebotomy-free in Phase 2, one shot every 3 months. It replaces the blood draw, not PharmaEssentia's Besremi." json: https://drugnews.com.tw/articles/2026-10-24-merck-kgaa-silence-divesiran-polycythemia-vera-besremi-en.json publisher: Drugnews｜藥時事 (https://drugnews.com.tw/) --- ## 三句看懂 - Iron-restricting drugs (Takeda's Mimrylo and Merck KGaA's divesiran) will replace routine phlebotomy in polycythemia vera but not PharmaEssentia's Besremi: PharmaEssentia's cumulative January-May 2027 consolidated revenue will still grow at least 30% year over year when reported in June 2027. - Merck KGaA announced on October 19, 2026 that it will acquire Silence Therapeutics for $20 per ADS in cash, about $1.3 billion, centered on the siRNA drug divesiran; closing is expected in Q1 2027. - In the 48-patient Phase 2 SANRECO trial, 88% of divesiran patients needed no phlebotomy in weeks 18-36 (placebo 19%); Takeda's weekly Mimrylo, FDA-approved on August 28, 2026, kept 76.9% phlebotomy-free in Phase 3 VERIFY (placebo 32.9%). ## 關鍵數字（附來源） | 項目 | 數值 | 日期 | 來源 | |---|---|---|---| | Merck KGaA acquisition of Silence Therapeutics, total value (announced 2026-10-19) | 1.3 USD billion | 2026-10-19 | https://www.fiercebiotech.com/biotech/merck-kgaa-buys-silence-13b-deal-biotechs-blood-cancer-sirna-drug | | Cash price per Silence ADS | 20 USD | 2026-10-19 | https://www.fiercebiotech.com/biotech/merck-kgaa-buys-silence-13b-deal-biotechs-blood-cancer-sirna-drug | | Expected closing of the Silence acquisition | Q1 2027 | 2026-10-19 | https://www.biopharmadive.com/news/merck-kgaa-rnai-13b-silence-buyout-blood-disorder-polycythemia-vera/833336/ | | Enterprise value of Merck KGaA's June 2026 Bio-Techne acquisition | 11.3 USD billion | 2026-10-19 | https://qz.com/merck-kgaa-silence-therapeutics-acquisition-biotech-101926 | | Patients enrolled in divesiran Phase 2 SANRECO | 48 patients | 2026-08-10 | https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera | | SANRECO weeks 18-36 phlebotomy-free response, divesiran | 88 % | 2026-08-10 | https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera | | SANRECO weeks 18-36 phlebotomy-free response, placebo | 19 % | 2026-08-10 | https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera | | SANRECO response, every-12-week dosing arm | 81.3 % | 2026-08-10 | https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera | | SANRECO mean phlebotomies per patient weeks 0-36, divesiran | 0.2 phlebotomies per patient | 2026-08-10 | https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera | | SANRECO mean phlebotomies per patient weeks 0-36, placebo | 2.1 phlebotomies per patient | 2026-08-10 | https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera | | FDA approval date of Mimrylo (rusfertide) | 2026-08-28 | 2026-08-28 | https://www.cancernetwork.com/view/fda-approves-rusfertide-in-polycythemia-vera | | Patients enrolled in Mimrylo Phase 3 VERIFY | 293 patients | 2026-08-28 | https://www.takeda.com/en-us/newsroom/news-releases/2026/fda-approval-mimrylo/ | | VERIFY phlebotomy-free over 32 weeks, Mimrylo | 76.9 % | 2026-08-28 | https://www.cancernetwork.com/view/fda-approves-rusfertide-in-polycythemia-vera | | VERIFY phlebotomy-free over 32 weeks, placebo | 32.9 % | 2026-08-28 | https://www.cancernetwork.com/view/fda-approves-rusfertide-in-polycythemia-vera | | Mimrylo injection-site reaction rate (most common adverse reaction) | 56 % | 2026-08-28 | https://www.takeda.com/en-us/newsroom/news-releases/2026/fda-approval-mimrylo/ | | Jakafi 2025 sales | 3.1 USD billion | 2026-08-31 | https://www.fiercepharma.com/pharma/cusp-pharmaessentia-gains-fda-label-expansion-besremi | | PharmaEssentia September 2026 consolidated revenue | 2.635 NT$ billion | 2026-10-06 | https://www.moneydj.com/kmdj/news/newsviewer.aspx?a=2b08dc30-0dfd-49b5-92d9-64fae652da38 | | PharmaEssentia September 2026 revenue growth year over year | 99.98 % | 2026-10-06 | https://www.moneydj.com/kmdj/news/newsviewer.aspx?a=2b08dc30-0dfd-49b5-92d9-64fae652da38 | | PharmaEssentia January-September 2026 cumulative revenue | 19.737 NT$ billion | 2026-10-06 | https://news.cnyes.com/news/id/6619391 | | PharmaEssentia January-September 2026 cumulative revenue growth | 83.54 % | 2026-10-06 | https://news.cnyes.com/news/id/6619391 | | Year of the previous new FDA approval for ET before Besremi's August 2026 label | 1997 year | 2026-08-31 | https://www.fiercepharma.com/pharma/cusp-pharmaessentia-gains-fda-label-expansion-besremi | | Consecutive years Ropeg (Besremi) listed as NCCN first-line PV option | 4 years | 2026-10-06 | https://news.cnyes.com/news/id/6619391 | | SANRECO response, every-6-week dosing arm | 93.8 % | 2026-08-10 | https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera | | Silence cash and equivalents as of June 30, 2026 | 72 USD million | 2026-06-30 | https://www.biopharmadive.com/news/merck-kgaa-rnai-13b-silence-buyout-blood-disorder-polycythemia-vera/833336/ | | Approximate US PV patient population (Takeda) | 90000 patients | 2026-08-28 | https://www.takeda.com/en-us/newsroom/news-releases/2026/fda-approval-mimrylo/ | $1.3 billion to retire the blood draw. On October 19, Germany's Merck KGaA agreed to buy UK RNA specialist Silence Therapeutics for $20 per American depositary share in cash, about $1.3 billion in total. It wanted one drug: divesiran. Divesiran treats polycythemia vera (PV), a rare blood cancer in which the bone marrow keeps churning out red blood cells. The blood thickens, clots become a real danger, and the standard fix is old-fashioned: come back to the clinic every few weeks and have a bag of blood drawn. In divesiran's Phase 2 trial, 88% of patients went from week 18 to week 36 without a single phlebotomy. Within three years, iron-restricting drugs will take routine phlebotomy out of PV care. What they replace is the blood draw, not PharmaEssentia's Besremi. ## 01 | Why pay $1.3 billion for a Phase 2 drug? Start with what Merck KGaA actually bought. Silence's most-hyped asset used to be zerlasiran, a cardiovascular drug, which fell into limbo after China's Hansoh Pharma walked away from a collaboration. AstraZeneca handed back its rights to another program, the ANGPTL3 drug SLN312, earlier this year. **The money is for one report card, delivered in August.** Silence's Phase 2 SANRECO trial enrolled 48 patients whose hematocrit stayed out of control despite hydroxyurea, interferon or Jakafi. They still needed phlebotomies. The results were blunt. On divesiran, 88% met the primary endpoint, against 19% on placebo. Over the first 36 weeks, patients on the drug averaged 0.2 phlebotomies each. The placebo group averaged 2.1. Several trips to the clinic a year became almost none. The response held up across both schedules. Patients dosed every six weeks responded at 93.8%; those dosed every 12 weeks, at 81.3%. Silence reported no new safety findings, infrequent and self-limiting injection-site reactions, and two cases of grade 1 anemia. For a drug that works by starving the marrow of iron, mild anemia is close to the expected side of the ledger. That is why a competitive sale process ended at $20 a share. Silence's interim principal executive Iain Ross described the outcome as "significant, immediate and certain value" for shareholders, and holders of about 14% of the voting power have already signed on. The deal still needs shareholder approval and the sanction of the High Court of England and Wales, with closing expected in the first quarter of 2027. Merck KGaA's chief executive Kai Beckmann framed the deal as part of an effort to "transform our pipeline toward areas of high specialization and unmet medical need." The company bought SpringWorks Therapeutics last year and agreed in June to acquire Bio-Techne at an enterprise value of about $11.3 billion. This time the target is a rare blood disease. The pattern is consistent. SpringWorks brought approved rare-tumor drugs; Bio-Techne brought tools and diagnostics; Silence brings a late-stage rare-disease asset that Merck KGaA will have to carry through Phase 3 itself. Silence had only $72 million in cash at the end of June, so the question was never whether divesiran would get a Phase 3, but who would pay for it. Merck KGaA has answered that. William Blair analyst Myles Minter put it more plainly: the deal "takes the execution risk off the table in an increasingly competitive space." Why is the space getting crowded? The answer sits outside the bone marrow. ## 02 | The disease lives in the marrow. The drugs work in the liver PV starts in the bone marrow. In most patients, blood stem cells carry a JAK2 mutation that acts like a stuck accelerator on a printing press for red cells. Red cells need iron as raw material. The body's iron thermostat is a liver hormone called hepcidin. When hepcidin rises, iron gets locked away in the gut and in storage cells, the marrow runs short, and red-cell production slows down. Phlebotomy, oddly enough, does the same job by brute force. Each draw pulls iron out along with the blood, keeping patients deliberately iron-deficient. The price is a clinic visit every few weeks and the fatigue that comes with low iron. The new drugs skip the needle-and-bag routine and simply narrow the iron gate. This matters to a lot of people. Takeda puts the US PV population at roughly 90,000. For many of them, the rhythm of the disease is set by the hematocrit test and the phlebotomy chair, not by any pill. A drug that holds hematocrit below 45% without the chair changes daily life more visibly than most cancer drugs do. ![Figure 1 | Three drugs, three targets](https://drugnews.com.tw/assets/articles/merck-kgaa-silence-divesiran-polycythemia-vera-besremi-en/figure-01.png) *Figure 1 | Iron-restricting drugs control the raw material in the liver and blood; Besremi works on the mutant source in the marrow* Takeda's Mimrylo (rusfertide) is a synthetic hepcidin mimetic: it adds the hormone from outside. Divesiran is an siRNA that silences TMPRSS6, a gene in liver cells, so the liver makes more of its own hepcidin. One tops up hepcidin every week. The other tells the liver to work overtime for three months. ## 03 | Weekly shots versus quarterly shots: Takeda has about three years The FDA approved Mimrylo on August 28, making it the first hepcidin mimetic for erythrocytosis in PV. In the Phase 3 VERIFY trial of 293 patients, 76.9% avoided phlebotomy over 32 weeks, compared with 32.9% on placebo. That is a solid result. The catch is the schedule. Patients inject Mimrylo themselves once a week, and injection-site reactions are the most common side effect on its label, at 56%. Divesiran was dosed every six or every 12 weeks in Phase 2. The 12-week arm still hit 81.3%, and Silence planned its Phase 3 around a 12-week schedule. ![Figure 2 | Share of patients free of phlebotomy](https://drugnews.com.tw/assets/articles/merck-kgaa-silence-divesiran-polycythemia-vera-besremi-en/figure-02.png) *Figure 2 | Both iron drugs push phlebotomy-free rates past three in four patients; the real difference is how often patients inject* The two trials differ in design, timing and patients, so the numbers belong side by side, not head to head. Even so, Cantor Fitzgerald argues divesiran "meaningfully exceeded" Mimrylo's efficacy and could get by with a smaller Phase 3 than VERIFY. | Same yardstick | Mimrylo | Divesiran | Besremi | |---|---|---|---| | Company | Takeda / Protagonist | Merck KGaA (via Silence) | PharmaEssentia | | Mechanism | Mimics hepcidin | Makes the liver produce more hepcidin | Long-acting interferon aimed at mutant cells | | Dosing | Weekly self-injection | Every 6–12 weeks | Every 2 weeks, stretchable to 4 once stable | | Controls | Red cells | Red cells | Red cells, platelets, white cells and the mutation | | US status | Approved Aug 2026 | Phase 3 planned 1H 2027 | Approved 2021; ET added Aug 2026 | ![Figure 3 | One yardstick for three PV drugs](https://drugnews.com.tw/assets/articles/merck-kgaa-silence-divesiran-polycythemia-vera-besremi-en/figure-03.png) *Figure 3 | The two iron drugs fight over the same slot; Besremi sits a layer below* If Phase 3 starts in the first half of 2027, divesiran is unlikely to reach a filing before around 2029. Those three years are Takeda's window to own the iron market and to build prescribing habits before a quarterly shot shows up. Takeda knows how much rides on this launch. Chief executive Julie Kim called the moment "an important inflection point" as the company prepares three new medicines. Mimrylo is the one in that group facing a better-dosed rival before it has even finished its first year on the market. Agios is also developing a TMPRSS6-silencing drug, so the quarterly-shot approach will not stay a one-company story either. There is a second, quieter loser. Incyte and Novartis' Jakafi sold $3.1 billion last year across myeloproliferative neoplasms. In PV, a large part of its job is pulling hematocrit down. Hepcidin drugs do that one job more precisely. ## 04 | Taiwan's PharmaEssentia: the layer iron drugs cannot reach Investors in PharmaEssentia, the Taipei-listed maker of Besremi, have an obvious worry. One big drugmaker after another is moving into PV. Does Besremi get squeezed? The answer is printed in Takeda's own label. Mimrylo carries a warning for new or worsening thrombocytosis and asks doctors to check blood counts every two to four weeks. Iron drugs control the raw material for red cells. They do nothing for platelets or white cells, and they never touch the JAK2 mutation itself. Besremi works at exactly that layer. It is a long-acting interferon designed to shrink the mutant clone, and the NCCN guidelines have listed it as a first-line option for both high- and low-risk PV for four straight years. **Iron drugs are add-ons: the SANRECO patients were already on interferon or other therapy when they enrolled.** The numbers line up with that reading. Mimrylo won approval in late August. PharmaEssentia's September consolidated revenue was NT$2.635 billion, up 99.98% year over year, and its first nine months reached NT$19.737 billion, up 83.54%. In August, Besremi also picked up a US label for essential thrombocythemia (ET), the FDA's first new ET approval since 1997. Big companies arriving tends to grow the disease category rather than shrink the incumbent. PharmaEssentia's US operations head Samuel Lin said in August that interest from larger players validates the opportunity in myeloproliferative neoplasms. Who gains and who gives ground from this deal is now easy to rank. Merck KGaA and Silence shareholders lock in value first. Takeda has to turn a weekly injection into volume inside three years. Jakafi loses part of its blood-control role in PV. Phlebotomy chairs get quieter. Besremi stays where it is. For readers in Taiwan, the deal is a rare case of a global buyout landing right next to a home-grown franchise. Besremi is PharmaEssentia's only commercial product, and 2025 revenue reached NT$15.63 billion, up 61%. The company's earlier fight was about getting interferon accepted as first-line care; the next one is about positioning it as the foundation that iron drugs sit on top of. Our piece last week, [PharmaEssentia won PV; its second front meets Merck & Co.'s $1.35 billion](https://drugnews.com.tw/articles/2026-10-17-pharmaessentia-china-et-approval-race.html), covered the ET front. Iron drugs open a different front, and Besremi is not the target there. The test comes in June 2027, when PharmaEssentia reports its May revenue. If cumulative January-to-May revenue is still growing 30% or more year over year, doctors spent Mimrylo's first year adding iron drugs alongside Besremi, not swapping it out. ![Figure 4 | From bloodletting to iron drugs](https://drugnews.com.tw/assets/articles/merck-kgaa-silence-divesiran-polycythemia-vera-besremi-en/figure-04.png) *Figure 4 | Besremi reached the US in 2021; the iron-drug race only started in 2026* This article is industry and company analysis, not investment or medical advice. ## References 1. Merck KGaA buys Silence in $1.3B deal after siRNA drug's phase 2 blood cancer win｜Fierce Biotech｜2026-10-19｜https://www.fiercebiotech.com/biotech/merck-kgaa-buys-silence-13b-deal-biotechs-blood-cancer-sirna-drug 2. Merck KGaA bets on RNAi with $1.3B Silence buyout｜BioPharma Dive｜2026-10-19｜https://www.biopharmadive.com/news/merck-kgaa-rnai-13b-silence-buyout-blood-disorder-polycythemia-vera/833336/ 3. Merck KGaA to buy Silence Therapeutics for $1.3 billion｜Quartz｜2026-10-19｜https://qz.com/merck-kgaa-silence-therapeutics-acquisition-biotech-101926 4. Silence Therapeutics letter to investigators on Merck KGaA acquisition (Form DEFA14A, Ex. 99.4)｜SEC｜2026-10-19｜https://www.sec.gov/Archives/edgar/data/0001479615/000119312526425238/d189864dex994.htm 5. Divesiran eliminates need for phlebotomy in 88% of patients with polycythemia vera｜CURE｜2026-08-10｜https://www.curetoday.com/view/divesiran-eliminates-need-for-phlebotomy-in-88-of-patients-with-polycythemia-vera 6. FDA Approves MIMRYLO (rusfertide) for Polycythemia Vera｜Takeda｜2026-08-28｜https://www.takeda.com/en-us/newsroom/news-releases/2026/fda-approval-mimrylo/ 7. FDA approves rusfertide in polycythemia vera｜CancerNetwork｜2026-08-28｜https://www.cancernetwork.com/view/fda-approves-rusfertide-in-polycythemia-vera 8. On the 'cusp,' PharmaEssentia gains FDA label expansion for Besremi｜Fierce Pharma｜2026-08-31｜https://www.fiercepharma.com/pharma/cusp-pharmaessentia-gains-fda-label-expansion-besremi 9. PharmaEssentia September revenue doubles year over year (in Chinese)｜Anue (cnyes)｜2026-10-06｜https://news.cnyes.com/news/id/6619391 10. PharmaEssentia September 2026 revenue NT$2.635 billion, up 99.98% (in Chinese)｜MoneyDJ｜2026-10-06｜https://www.moneydj.com/kmdj/news/newsviewer.aspx?a=2b08dc30-0dfd-49b5-92d9-64fae652da38 11. Besremi (ropeginterferon alfa-2b) prescribing information｜Drugs.com｜2026-10-20｜https://www.drugs.com/pro/besremi.html