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Pertuzumab
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The structure of HER2 and pertuzumab | |
| Monoclonal antibody | |
|---|---|
| Type | Whole antibody |
| Source | Humanized (from mouse) |
| Target | HER2 |
| Clinical data | |
| Trade names | Perjeta |
| Other names | 2C4 |
| Biosimilars | pertuzumab-dpzb,[1][2] Poherdy[1][2] |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a612027 |
| License data |
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| Pregnancy category |
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| Routes of administration | Intravenous |
| Drug class | Antineoplastic |
| ATC code | |
| Legal status | |
| Legal status | |
| Identifiers | |
| CAS Number | |
| DrugBank | |
| ChemSpider |
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| KEGG | |
| ChEMBL | |
Pertuzumab, sold under the brand name Perjeta among others, is a monoclonal antibody used in combination with trastuzumab and docetaxel for the treatment of metastatic HER2-positive breast cancer; it also used in the same combination as a neoadjuvant in early HER2-positive breast cancer.[5]
Side effects in more than half the people taking it include diarrhea, hair loss, and loss of neutrophils; more than 10% experience loss of red blood cells, hypersensitivity or allergic reaction, infusion reactions, decreased appetite, insomnia, distortions in the sense of taste, inflammation of the mouth or lips, constipation, rashes, nail disease, and muscle pain.[4] Women who are pregnant or planning on getting pregnant should not take it, it was not studied in people with certain heart conditions and should be used in caution in such people, and it should not be used with an anthracycline.[4] It is unknown if pertuzumab interacts with doxorubicin.[4]
It is the first-in-class of a kind of medication called a "epidermal growth factor receptor (HER) dimerization inhibitor" — it inhibits the dimerization of HER2 with other HER receptors, which prevents them from signalling in ways that promote cell growth and proliferation.[7]
It was discovered and developed by Genentech and was first approved in 2012.[8][9]
Medical uses
[edit]Pertuzumab is administered as an intravenous infusion in combination with trastuzumab and docetaxel as a first line treatment for HER2-positive metastatic breast cancer.[5][4]
Women of child-bearing age should use contraception while taking pertuzumab; it may damage the fetus in pregnant women, and it may be secreted in breast milk.[4]
Adverse effects
[edit]In clinical trials of the three-agent combination therapy in metastatic breast cancer, adverse effects occurring in more than half the people taking it included diarrhea, hair loss, and loss of neutrophils; more than 10% of people experienced loss of neutrophils with fever, and loss of leukocytes.[4] After docetaxel was dropped in some people, the most common adverse effects were diarrhea (28.1%), upper respiratory tract infection (18.3%), rash (18.3%), headache (17.0%), fatigue (13.4%), swelling of nasal passages and throat (often due to catching the common cold) (17.0%), weakness (13.4%), itchiness (13.7%), joint pain (11.4%), nausea (12.7%), pain in an extremity (13.4%), back pain (12.1%) and cough (12.1%).[4]
In clinical trials of the neoadjuvant use of the combination, more than 50% of people had hair loss and loss of neutrophils.[4]
In both uses, more than 10% of people additionally experienced: loss of red blood cells, hypersensitivity or allergic reaction, infusion reactions, decreased appetite, insomnia, distortions in the sense of taste, inflammation of the mouth or lips, constipation, rashes, nail disease, and muscle pain.[4]
Pharmacology
[edit]The metabolism of pertuzumab has not been directly studied; in general antibodies are cleared principally by catabolism. The median clearance of pertuzumab was 0.235 liters/day and the median half-life was 18 days.[4]
Mechanism of action
[edit]HER2 is an extracellular receptor—a receptor tyrosine kinase - that when activated, sets off signal transduction through several pathways that stimulate cell proliferation and cell growth; if overexpressed it can cause uncontrollable growth. HER2 positive breast cancer is caused by ERBB2 gene amplification that results in overexpression of HER2 in approximately 15-30% of breast cancer tumors.[10]
HER2 normally combines another protein in order to function (a process called dimerization); it can bind with a second HER2 receptor (acting as a homodimer) and it can heterodimerize with a different receptor of the HER family. The most potent dimer for activating signalling pathways is HER2/HER3.[7]
The epitope for pertuzumab is the domain of HER2 where it binds to HER3, and pertuzumab prevents the HER2/HER3 dimer from forming, which blocks signalling by the dimer.[7][11] Trastuzumab is another monoclonal antibody against HER2; its epitope is the domain where HER2 binds to another HER2 protein.[7] The two mAbs together prevent HER2 from functioning.[7]
Chemistry and manufacturing
[edit]Pertuzumab is an immunoglobulin G1 with a variable region against the human HER2 protein, a human-mouse monoclonal 2C4 heavy chain, disulfide bound with a human-mouse monoclonal 2C4 κ-chain.[12]
History
[edit]The monoclonal antibody 2C4 appears to have first been published in 1990 by scientists from Genentech,[13] the same year that F. Hoffmann-La Roche AG acquired a majority stake in Genentech.[14]
By 2003, Genentech understood that 2C4 prevented HER2 dimerizing with other HER receptors and had begun Phase I trials, aiming for a broad range of cancers, not just ones overexpressing HER2. It was the first known HER dimerization inhibitor.[15]
In 2005, Genentech presented poor results of Phase II trials of pertuzumab as a single agent in prostate, breast, and ovarian cancers, and said that it intended to continue developing it in combination with other drugs for ovarian cancer.[16][17]
In 2007, Genentech dropped the trade name Omnitarg.[18][19]
In March 2009, Roche acquired Genentech.[20][21]
In 2012, the results were published of the CLEOPATRA trial, a randomized placebo-controlled Phase III trial of pertuzumab in combination with trastuzumab and docetaxel in HER2-positive metastatic breast cancer.[22] Pertuzumab received US FDA approval for the treatment of HER2-positive metastatic breast cancer later that year.[9] Results of a Phase II trial in the neoadjuvant setting, NeoSphere, published in 2012,[23] and results of a Phase II cardiac safety study in the same population, Tryphaena, published in 2013.[24] The FDA approved the neoadjuvant indication in 2013.[25]
Pertuzumab was approved for medical use in the European Union in 2013.[4][6]
Cliincal Trials
[edit]APHINITY study
[edit]The phase III APHINITY study demonstrated statistically significant long-term survival benefits for people with HER2-positive early-stage breast cancer. After ten years, individuals treated with pertuzumab, trastuzumab and chemotherapy (the pertuzumab-based regimen) showed a 17% reduction in the risk of death compared to those receiving trastuzumab, chemotherapy, and placebo as adjuvant therapy.[26][27]
The study showed that 91.6% of patients treated with the pertuzumab-based regimen were alive after ten years, compared to 89.8% of those receiving the placebo regimen. A clinically significant reduction in the risk of death was observed in the pre-specified subgroup of patients with lymph node-positive disease (21% reduction, HR=0.79). No benefit was observed in the node-negative subgroup.[26][27]
Society and culture
[edit]Legal status
[edit]Biosimilars
[edit]In November 2025, the biosimilar pertuzumab-dpzb (Poherdy) was approved for medical use in the United States as an interchangeable biosimilar to Perjeta.[2] It is the first approval of a biosimilar for Perjeta.[2]
Economics
[edit]As of 2016[update], in the US each cycle of the three-drug combination given every three weeks costs around US$8,500, not including ancillary care costs.[28]
In the UK, a NICE evaluation in 2015, made a preliminary finding that the drug combination was not cost effective, and NICE rejected the drug in the neoadjuvant setting in May 2016, primarily because it was unknown if the drug combination provided a survival benefit.[29][30][31] This decision was subsequently reversed six months later and pertuzumab became the first new breast cancer drug to be approved by NICE for routine NHS funding in almost a decade after Roche pledged to provide the drug to the NHS at an undisclosed discount for patients in the neoadjuvant setting and to share the long–term financial risks.[32]
References
[edit]- ^ a b https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761450s000lbl.pdf
- ^ a b c d "FDA approves new interchangeable biosimilar to Perjeta". U.S. Food and Drug Administration (FDA). 13 November 2025. Retrieved 14 November 2025.
This article incorporates text from this source, which is in the public domain.
- ^ a b "AUSTRALIAN PRODUCT INFORMATION – Perjeta® (pertuzumab)". Retrieved 12 July 2024.
- ^ a b c d e f g h i j k l "Perjeta 420 mg Concentrate for Solution for Infusion — Summary of Product Characteristics (SmPC)". (emc). 2 July 2021. Archived from the original on 3 January 2022. Retrieved 3 January 2022.
- ^ a b c d "Perjeta- pertuzumab injection, solution, concentrate". DailyMed. Archived from the original on 25 March 2021. Retrieved 3 January 2022.
- ^ a b "Perjeta EPAR". European Medicines Agency (EMA). 17 September 2018. Archived from the original on 16 September 2021. Retrieved 3 January 2022.
- ^ a b c d e Harbeck N, Beckmann MW, Rody A, Schneeweiss A, Müller V, Fehm T, et al. (March 2013). "HER2 Dimerization Inhibitor Pertuzumab — Mode of Action and Clinical Data in Breast Cancer". Breast Care. 8 (1): 49–55. doi:10.1159/000346837. PMC 3971793. PMID 24715843.
- ^ "Drug Approval Package: Perjeta (pertuzumab) Injection NDA #125409". U.S. Food and Drug Administration (FDA). 3 August 2012. Archived from the original on 3 January 2022. Retrieved 3 January 2022.
- ^ a b "FDA approves Perjeta for type of late-stage breast cancer". U.S. Food and Drug Administration (FDA). 8 June 2012. Archived from the original on 1 November 2012. Retrieved 3 January 2022.
- ^ Mitri Z, Constantine T, O'Regan R (2012). "The HER2 Receptor in Breast Cancer: Pathophysiology, Clinical Use, and New Advances in Therapy". Chemotherapy Research and Practice. 2012 743193. doi:10.1155/2012/743193. PMC 3539433. PMID 23320171.
- ^ Badache A, Hynes NE (April 2004). "A new therapeutic antibody masks ErbB2 to its partners". Cancer Cell. 5 (4): 299–301. doi:10.1016/s1535-6108(04)00088-1. PMID 15093533.
- ^ "Proposed INN: List 89" (PDF). WHO Drug Information. 17 (3). 2003. Archived (PDF) from the original on 9 August 2020. Retrieved 5 October 2020.
- ^ Fendly BM, Winget M, Hudziak RM, Lipari MT, Napier MA, Ullrich A (March 1990). "Characterization of murine monoclonal antibodies reactive to either the human epidermal growth factor receptor or HER2/neu gene product" (PDF). Cancer Research. 50 (5): 1550–1558. PMID 1689212. Archived (PDF) from the original on 29 September 2019. Retrieved 2 November 2016., referenced in Molina MA, Codony-Servat J, Albanell J, Rojo F, Arribas J, Baselga J (June 2001). "Trastuzumab (herceptin), a humanized anti-Her2 receptor monoclonal antibody, inhibits basal and activated Her2 ectodomain cleavage in breast cancer cells" (PDF). Cancer Research. 61 (12): 4744–4749. PMID 11406546. Archived (PDF) from the original on 29 September 2019. Retrieved 2 November 2016.
- ^ Fisher LM (1 October 2000). "Genentech: Survivor Strutting Its Stuff". The New York Times. Archived from the original on 20 December 2016. Retrieved 19 February 2017.
- ^ Albanell J, Codony J, Rovira A, Mellado B, Gascón P (2003). "Mechanism of Action of Anti-Her2 Monoclonal Antibodies: Scientific Update on Trastuzumab and 2c4". New Trends in Cancer for the 21stCentury. Advances in Experimental Medicine and Biology. Vol. 532. Springer. pp. 253–68. doi:10.1007/978-1-4615-0081-0_21. ISBN 978-0-306-47762-1. PMID 12908564.
- ^ "Press Release: Data From Omnitarg Clinical Program Presented at American Society of Clinical Oncology Meeting". Genentech. 15 May 2005. Archived from the original on 6 April 2017. Retrieved 2 November 2016.
- ^ "Genentech's Omnitarg fails in Phase II". Pharma Times. 16 May 2005. Archived from the original on 24 February 2021. Retrieved 2 November 2016.
- ^ "Correction: Letter from the Editor". Cancer Oncology News: 3. February 2012. Archived from the original on 4 November 2016. Retrieved 2 November 2016.
- ^ "Press release: Roche in the first half of 2007". Roche. 19 July 2007. Archived from the original on 4 November 2016. Retrieved 2 November 2016.
- ^ Morse A (10 May 2006). "Chugai Shares Post Healthy Gain On Prospects for Cancer Drug". The Wall Street Journal. Archived from the original on 20 October 2021. Retrieved 26 September 2008.
- ^ "Roche Makes $43.7B Bid for Genentech". Genetic Engineering & Biotechnology News. 21 July 2008. Archived from the original on 3 February 2009. Retrieved 26 September 2008.
- ^ Baselga J, Cortés J, Kim SB, Im SA, Hegg R, Im YH, et al. (January 2012). "Pertuzumab plus trastuzumab plus docetaxel for metastatic breast cancer". The New England Journal of Medicine. 366 (2): 109–119. doi:10.1056/nejmoa1113216. PMC 5705202. PMID 22149875.
- ^ Gianni L, Pienkowski T, Im YH, Roman L, Tseng LM, Liu MC, et al. (January 2012). "Efficacy and safety of neoadjuvant pertuzumab and trastuzumab in women with locally advanced, inflammatory, or early HER2-positive breast cancer (NeoSphere): a randomised multicentre, open-label, phase 2 trial". The Lancet. Oncology. 13 (1): 25–32. doi:10.1016/s1470-2045(11)70336-9. PMID 22153890. cited in Mates M, Fletcher GG, Freedman OC, Eisen A, Gandhi S, Trudeau ME, et al. (March 2015). "Systemic targeted therapy for her2-positive early female breast cancer: a systematic review of the evidence for the 2014 Cancer Care Ontario systemic therapy guideline". Current Oncology. 22 (Suppl 1): S114 – S122. doi:10.3747/co.22.2322. PMC 4381787. PMID 25848335.
- ^ Schneeweiss A, Chia S, Hickish T, Harvey V, Eniu A, Hegg R, et al. (September 2013). "Pertuzumab plus trastuzumab in combination with standard neoadjuvant anthracycline-containing and anthracycline-free chemotherapy regimens in patients with HER2-positive early breast cancer: a randomized phase II cardiac safety study (TRYPHAENA)". Annals of Oncology. 24 (9): 2278–2284. doi:10.1093/annonc/mdt182. PMID 23704196.
- ^ "FDA approves Perjeta for neoadjuvant breast cancer treatment". U.S. Food and Drug Administration (FDA) (Press release). 30 September 2013. Archived from the original on 10 October 2013. Retrieved 3 January 2022.
- ^ a b Hoffmann-La Roche (18 December 2024). A Randomized Multicenter, Double-Blind, Placebo-Controlled Comparison of Chemotherapy Plus Trastuzumab Plus Placebo Versus Chemotherapy Plus Trastuzumab Plus Pertuzumab as Adjuvant Therapy in Patients With Operable HER2-Positive Primary Breast Cancer (Report). clinicaltrials.gov.
- ^ a b "Roche's Perjeta-based breast cancer regimen shows sustained survival benefits - PMLiVE". pmlive.com. 14 May 2025. Retrieved 20 May 2025.
- ^ Durkee BY, Qian Y, Pollom EL, King MT, Dudley SA, Shaffer JL, et al. (March 2016). "Cost-Effectiveness of Pertuzumab in Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer". Journal of Clinical Oncology. 34 (9): 902–909. doi:10.1200/jco.2015.62.9105. PMC 5070553. PMID 26351332.
- ^ Fleeman N, Bagust A, Beale S, Dwan K, Dickson R, Proudlove C, et al. (January 2015). "Pertuzumab in combination with trastuzumab and docetaxel for the treatment of HER2-positive metastatic or locally recurrent unresectable breast cancer". PharmacoEconomics. 33 (1): 13–23. doi:10.1007/s40273-014-0206-2. PMID 25138171. S2CID 8470253.
- ^ "Breast cancer (HER2 positive, metastatic) - pertuzumab (with trastuzumab and docetaxel) [ID523]". NICE. 1 September 2016. Archived from the original on 4 November 2016. Retrieved 2 November 2016.
- ^ McKee S (20 May 2016). "NICE rejects Roche's breast cancer drug Perjeta". Pharma Times. Archived from the original on 3 March 2021. Retrieved 2 November 2016.
- ^ Yip A (22 November 2016). "NICE U-Turns and Backs Approval of Roche's Perjeta for HER2-Positive Breast Cancer". Pharmalive. Archived from the original on 7 April 2017. Retrieved 7 April 2017.
Further reading
[edit]- Dean L (2015). "Pertuzumab Therapy and ERBB2 (HER2) Genotype". In Pratt VM, McLeod HL, Rubinstein WS, et al. (eds.). Medical Genetics Summaries. National Center for Biotechnology Information (NCBI). PMID 28520364. Bookshelf ID: NBK315949.
External links
[edit]- "Pertuzumab ( Code - C38692 )". EVS Explore.
Pertuzumab
View on GrokipediaPertuzumab is a recombinant humanized monoclonal antibody that targets the human epidermal growth factor receptor 2 (HER2), a protein overexpressed in certain aggressive cancers, most notably HER2-positive breast cancer. Developed by Genentech, a member of the Roche Group, it functions by binding to subdomain II of the HER2 extracellular domain, thereby inhibiting the dimerization of HER2 with other HER family receptors such as HER3 and preventing ligand-dependent activation of downstream signaling pathways that promote tumor cell proliferation and survival.[1][2][3]
The U.S. Food and Drug Administration first approved pertuzumab in June 2012 for use in combination with trastuzumab and docetaxel to treat patients with HER2-positive metastatic breast cancer who had not received prior anti-HER2 therapy or chemotherapy for metastatic disease.[4] Subsequent approvals expanded its indications to include neoadjuvant therapy with trastuzumab and chemotherapy for HER2-positive locally advanced, inflammatory, or early-stage breast cancer at high risk of recurrence, as well as adjuvant treatment following surgery and neoadjuvant therapy in node-positive cases.[5][6] In 2020, a subcutaneous fixed-dose combination formulation incorporating pertuzumab, trastuzumab, and hyaluronidase-zzxf (PHESGO) received approval, offering an alternative to intravenous administration for eligible patients with HER2-positive breast cancer.[7] Its mechanism complements trastuzumab by targeting a distinct HER2 epitope, enhancing antitumor activity without overlapping binding sites, as demonstrated in clinical trials showing improved progression-free survival when combined.[8][9]
Medical Applications
Approved Indications
Pertuzumab is approved by the U.S. Food and Drug Administration (FDA) for use in combination with trastuzumab and docetaxel in adults with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease; this indication received initial approval on June 8, 2012.[10] The FDA has also approved pertuzumab, in combination with trastuzumab and chemotherapy (such as docetaxel or carboplatin plus docetaxel), for neoadjuvant treatment of adults with HER2-positive, locally advanced, inflammatory, or early-stage breast cancer (tumors greater than 2 cm in diameter or node-positive) as part of a complete treatment regimen; this expansion was approved on October 17, 2013.[11] Additionally, pertuzumab is indicated, in combination with trastuzumab and chemotherapy (such as docetaxel or paclitaxel with carboplatin), for the adjuvant treatment of adults with HER2-positive early breast cancer at high risk of recurrence; accelerated approval was granted in 2016 and converted to full approval on December 20, 2017, based on the APHINITY trial demonstrating improved invasive disease-free survival.[5] The European Medicines Agency (EMA) has authorized similar indications, including combination with trastuzumab and docetaxel for HER2-positive metastatic or locally recurrent unresectable breast cancer, as well as neoadjuvant and adjuvant settings in eligible patients, with initial approval in 2012 followed by expansions.[12] Approvals require confirmation of HER2-positive status via FDA-approved diagnostic tests, such as immunohistochemistry or fluorescence in situ hybridization.[13] Pertuzumab is not approved as monotherapy or for HER2-negative breast cancer or other malignancies.[11]Efficacy Data from Key Studies
The phase III CLEOPATRA trial evaluated pertuzumab added to trastuzumab and docetaxel as first-line therapy for HER2-positive metastatic breast cancer in 808 patients randomized to pertuzumab (n=402) or placebo (n=406). Median progression-free survival (PFS) by independent review was 18.5 months in the pertuzumab arm versus 12.4 months in the placebo arm (hazard ratio [HR] 0.62, 95% CI 0.51-0.75; p<0.001). Final overall survival (OS) analysis at a median follow-up of 50.3 months showed a median OS of 56.5 months versus 40.8 months (HR 0.68, 95% CI 0.56-0.84; p=0.0002), confirming a 32% reduction in mortality risk.[14]| Endpoint | Pertuzumab Arm | Placebo Arm | HR (95% CI) | p-value |
|---|---|---|---|---|
| Median PFS (months) | 18.5 | 12.4 | 0.62 (0.51-0.75) | <0.001 |
| Median OS (months) | 56.5 | 40.8 | 0.68 (0.56-0.84) | 0.0002 |
Safety and Tolerability
Common Adverse Effects
The most common adverse reactions (incidence >30%) observed with pertuzumab in combination with trastuzumab and docetaxel in patients with HER2-positive metastatic breast cancer from the CLEOPATRA trial were diarrhea (66.8% vs. 45.5% in placebo arm), alopecia (60.9% vs. 58.4%), neutropenia (49.0% vs. 45.8%), nausea (39.3% vs. 30.8%), and fatigue (21.0% vs. 19.2%).[18] [19] Grade 3 or 4 neutropenia was the most frequent severe event (49% in pertuzumab arm vs. 46% in placebo), often linked to docetaxel exposure, with febrile neutropenia occurring in 13.3% vs. 7.8%.[19] [20] Diarrhea was notably increased with pertuzumab addition (any grade: 66.8%), typically mild to moderate and manageable with supportive care, though grade 3 events reached 7.8% vs. 5.0% in controls.[19] [21] Other frequent effects (>20% incidence) included rash (28.1% vs. 21.3%), mucosal inflammation (23.9% vs. 17.0%), and peripheral neuropathy (21.4% vs. 18.0%), reflecting additive toxicities from the regimen rather than pertuzumab-specific signals.[19] Infusion-related reactions occurred in 11% of pertuzumab-treated patients, manifesting as hypersensitivity, fatigue, or vomiting, but were rarely severe.[22]| Adverse Reaction | Any Grade Incidence (Pertuzumab Arm) | Grade 3-4 Incidence (Pertuzumab Arm) |
|---|---|---|
| Diarrhea | 66.8% | 7.8% |
| Alopecia | 60.9% | <1% |
| Neutropenia | 49.0% | 49.0% |
| Nausea | 39.3% | 1.0% |
| Fatigue | 21.0% | 2.0% |
Serious Risks and Long-Term Concerns
Pertuzumab, when administered in combination with trastuzumab and chemotherapy, is associated with a higher incidence of serious adverse events compared to regimens without pertuzumab, with rates of 36% versus 29% in the CLEOPATRA trial for metastatic breast cancer.[24] Left ventricular dysfunction, including subclinical decreases in ejection fraction and clinical heart failure, represents a primary serious risk, prompting a boxed warning from the FDA due to potential for symptomatic congestive heart failure; in pivotal trials, confirmed significant left ventricular systolic dysfunction occurred in 1.5% of pertuzumab-treated patients versus 0.8% in controls.[25] [26] Infusion-related reactions, which can be severe or fatal, occur in up to 20% of patients receiving pertuzumab alone on the first day of administration, manifesting as fever, chills, fatigue, wheezing, or bronchospasm, with fatalities reported in post-marketing surveillance; premedication and monitoring are required to mitigate these hypersensitivity events.[27] [25] Severe neutropenia, febrile neutropenia, and diarrhea (grade 3 or higher) are also elevated, with disproportionate signals for cardiotoxicity, neutropenia, and gastrointestinal events in real-world pharmacovigilance analyses of the FDA Adverse Event Reporting System.[28] Embryo-fetal toxicity constitutes another boxed warning, as pertuzumab can cause fetal harm based on its mechanism and animal data showing oligohydramnios, delayed kidney development, and embryo-fetal death; effective contraception is mandated during treatment and for seven months post-therapy in females of reproductive potential.[25] In fixed-dose combinations like PHESGO (pertuzumab plus trastuzumab), additional risks include serious pulmonary toxicity such as interstitial pneumonitis, pleural effusions, and non-cardiogenic pulmonary edema, though causality specific to pertuzumab remains under evaluation in ongoing safety monitoring.[29] Long-term concerns center on sustained cardiotoxicity, necessitating echocardiographic monitoring every three months during therapy and up to three years post-adjuvant treatment, as HER2 inhibition may lead to irreversible dysfunction in a subset of patients despite overall maintained cardiac safety in extended follow-ups like APHINITY (8-year data showing low event rates).[25] [30] No definitive evidence links pertuzumab to increased secondary malignancies or fertility impairment beyond pregnancy risks, but real-world safety requires continuous pharmacovigilance given its widespread use in HER2-positive breast cancer; grade 3-5 cardiac and hypersensitivity events remain rare but persistent in long-term cohorts.[28][31]Pharmacological Profile
Mechanism of Action
Pertuzumab is a recombinant humanized monoclonal antibody that selectively binds to subdomain II of the extracellular domain of the human epidermal growth factor receptor 2 (HER2) protein.[2] This binding site, also known as the dimerization domain, is critical for HER2's interaction with ligand-bound partner receptors in the ErbB family.[3] By occupying this region, pertuzumab sterically hinders the formation of HER2-containing heterodimers, particularly with HER3, which is the most potent signaling partner for HER2.[8] The inhibition of heterodimerization disrupts ligand-dependent activation of downstream signaling pathways, including the phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK) cascades, thereby suppressing cell proliferation, survival, and angiogenesis in HER2-overexpressing tumor cells.[32] Unlike trastuzumab, which binds to subdomain IV of HER2 and primarily inhibits ligand-independent homodimerization and induces receptor internalization, pertuzumab's action complements trastuzumab by targeting a distinct epitope, enabling dual blockade of HER2 signaling.[15] Additionally, pertuzumab mediates antibody-dependent cellular cytotoxicity (ADCC) by recruiting immune effector cells to HER2-positive targets.[8] Preclinical studies have demonstrated that pertuzumab's dimerization inhibition is effective against heregulin (HRG)-dependent HER2/HER3 signaling in various cancer cell lines, reducing phosphorylation of HER3 and downstream effectors.[33] Structural analyses, including cryo-electron microscopy, confirm that pertuzumab binds near the center of HER2 domain II, preventing the dimerization arm from engaging with partners like EGFR or HER3.[34] This mechanism underpins its synergistic antitumor effects when combined with trastuzumab in HER2-positive malignancies.[35]Pharmacokinetics and Drug Interactions
Pertuzumab exhibits linear pharmacokinetics following intravenous administration, with steady-state concentrations achieved after the first maintenance dose. The recommended dosing regimen consists of a loading dose of 840 mg followed by 420 mg every three weeks in combination with other agents such as trastuzumab and docetaxel.[25] The median terminal half-life of pertuzumab is 18 days, and the median clearance is 0.24 L/day, based on population pharmacokinetic analyses across various patient populations. As a monoclonal antibody, pertuzumab is primarily catabolized into smaller peptides and amino acids via proteolytic pathways, with minimal involvement of cytochrome P450 enzymes. Volume of distribution at steady state is approximately 3.5–7.5 L, consistent with distribution primarily into the vascular and extracellular space.[25][2] No clinically significant differences in pertuzumab pharmacokinetics have been observed based on age (including patients ≥65 years), sex, race/ethnicity (e.g., Asian vs. non-Asian), or mild to moderate renal impairment (creatinine clearance 30–90 mL/min). The pharmacokinetics in patients with severe renal impairment or any degree of hepatic impairment remain uncharacterized, precluding specific dosing recommendations. When co-administered with trastuzumab, no meaningful alterations in pertuzumab exposure occur, though the combination may influence overall regimen tolerability.[25] Pertuzumab has no established formal drug-drug interactions via metabolic pathways, as it does not inhibit or induce cytochrome P450 enzymes or transporters. However, caution is advised with concomitant use of other HER2-targeted therapies (e.g., trastuzumab) due to potential additive cardiotoxicity, and live vaccines should be avoided owing to immunosuppression risks. Additive adverse effects, such as hypersensitivity or neutropenia, may arise in combinations with myelosuppressive chemotherapies like docetaxel. No severe interactions with common medications are documented in prescribing information.[25][36][2]Clinical Development
Preclinical and Early-Phase Trials
Preclinical investigations of pertuzumab, initially developed as the monoclonal antibody 2C4 by Genentech, focused on its binding to subdomain II of the HER2 extracellular domain, which sterically hinders ligand-induced heterodimerization with EGFR, HER3, and HER4. In vitro assays demonstrated inhibition of heregulin-stimulated HER2-HER3 dimerization and downstream signaling in cells with varying HER2 expression levels, contrasting with trastuzumab's emphasis on HER2 homodimerization blockade.[1][37] In vivo xenograft models revealed antitumor activity as a monotherapy, including 59% growth inhibition in low-HER2 MCF7 breast cancer xenografts and efficacy against prostate and ovarian tumors. Combination with trastuzumab yielded synergistic effects through complementary mechanisms, promoting greater tumor regression in HER2-overexpressing models compared to either agent alone, without increased toxicity in non-human primates. These findings supported advancement to clinical testing, highlighting pertuzumab's potential to address trastuzumab resistance via non-overlapping HER2 inhibition.[9][37][1] The inaugural phase I trial, reported by Agus et al. in 2005, enrolled 21 patients with advanced solid tumors refractory to standard therapy, administering intravenous pertuzumab via dose escalation (0.5–15 mg/kg every 3 weeks). No dose-limiting toxicities occurred, establishing tolerability; of 365 adverse events, 122 were possibly related and mostly grade 1–2 (e.g., diarrhea, fatigue). Pharmacokinetics exhibited linearity akin to humanized IgG1 antibodies, with a ~15-day half-life enabling every-3-week scheduling and trough concentrations exceeding pharmacodynamic targets above 5 mg/kg. Antitumor signals included two partial responses (in ovarian and pancreatic cancers, lasting 10–11 months) and stable disease in six patients for 2.6–5.5 months.[38][39] Phase Ib evaluations combined pertuzumab with trastuzumab in advanced cancer patients, confirming safety with predominantly mild adverse events such as fatigue, nausea, and vomiting; no unexpected toxicities emerged, supporting further combination exploration. These early trials established a recommended phase II dose of 840 mg loading followed by 420 mg maintenance, paving the way for efficacy assessments in HER2-positive malignancies.[40]Pivotal Clinical Trials
The CLEOPATRA trial (NCT00567190) was a multicenter, randomized, double-blind, placebo-controlled phase III study that evaluated pertuzumab added to trastuzumab and docetaxel as first-line therapy for 808 patients with HER2-positive metastatic breast cancer who had not received prior anti-HER2 therapy or chemotherapy for advanced disease.[41] Patients were randomized 1:1 to receive pertuzumab (840 mg loading dose, then 420 mg every 3 weeks) plus trastuzumab (initial 8 mg/kg, then 6 mg/kg every 3 weeks) and docetaxel (75 mg/m² every 3 weeks, escalating to 100 mg/m² if tolerated) or the same regimen with placebo substituting for pertuzumab.[19] The primary endpoint was progression-free survival (PFS) by independent review. Median PFS was 18.5 months in the pertuzumab group versus 12.4 months in the placebo group (hazard ratio [HR] 0.62; 95% confidence interval [CI], 0.51-0.75; p<0.001).[19] An updated analysis confirmed overall survival (OS) benefit, with median OS of 56.5 months versus 40.8 months (HR 0.68; 95% CI, 0.56-0.84; p<0.001).[30] These findings established dual HER2 blockade as superior to trastuzumab alone with chemotherapy and supported initial U.S. Food and Drug Administration (FDA) approval of pertuzumab on June 8, 2012, for this indication.[5] The APHINITY trial (NCT01358877) was a phase III, randomized, double-blind, placebo-controlled study involving 4,805 patients with HER2-positive early breast cancer (node-positive or high-risk node-negative) who had undergone surgery and were candidates for adjuvant chemotherapy.[15] Participants received standard adjuvant chemotherapy (typically anthracycline- and taxane-based) with trastuzumab (8 mg/kg loading, then 6 mg/kg every 3 weeks for 1 year) plus either pertuzumab (840 mg loading, then 420 mg every 3 weeks for 1 year) or placebo.[15] The primary endpoint was invasive disease-free survival (iDFS) at 3 years in the intention-to-treat population. At a median follow-up of 45 months, 3-year iDFS rates were 94.1% with pertuzumab versus 93.2% with placebo (HR 0.81; 95% CI, 0.66-1.00; p=0.045).[15] Subgroup analysis showed greater benefit in node-positive patients (HR 0.77; 95% CI, 0.62-0.96), with 3-year iDFS of 92.3% versus 90.6%.[15] OS data were immature at primary analysis but trended favorably. These results led to FDA approval of adjuvant pertuzumab on December 20, 2017, specifically for node-positive disease at high risk of recurrence.[5]| Trial | Population | Key Endpoints and Results |
|---|---|---|
| CLEOPATRA | HER2+ metastatic breast cancer (n=808) | Median PFS: 18.5 vs. 12.4 months (HR 0.62, p<0.001); Median OS: 56.5 vs. 40.8 months (HR 0.68, p<0.001)[30] |
| APHINITY | HER2+ early breast cancer post-surgery (n=4,805) | 3-year iDFS: 94.1% vs. 93.2% (HR 0.81, p=0.045); Node-positive subgroup HR 0.77[15] |
Recent and Ongoing Research
Recent phase 3 trials have explored pertuzumab in combination with novel agents for first-line treatment of HER2-positive metastatic breast cancer. The DESTINY-Breast09 study, presented at ASCO 2025, demonstrated that trastuzumab deruxtecan plus pertuzumab improved median progression-free survival to 40.7 months compared to 27.0 months with the standard trastuzumab-pertuzumab-taxane regimen, representing a 44% reduction in the risk of disease progression or death (hazard ratio 0.56; 95% CI 0.47-0.68).[42] This led to FDA Breakthrough Therapy Designation in July 2025 and Priority Review in September 2025 for this combination, with a decision anticipated in Q1 2026.[43][44] Updated long-term data from adjuvant settings continue to support pertuzumab's role. In the APHINITY trial's node-positive cohort, 8-year invasive disease-free survival reached 86.1% with pertuzumab added to trastuzumab and chemotherapy, versus 81.2% without (hazard ratio 0.72; 95% CI 0.58-0.90), confirming a 4.9% absolute benefit.[45] Similarly, the PHranceSCa study reinforced the safety and efficacy of fixed-dose subcutaneous pertuzumab-trastuzumab over extended follow-up, with no new signals beyond known cardiac risks.[31] Research into de-escalation and retreatment strategies has advanced. The neoCARHP phase 2 trial, reported at ASCO 2025, evaluated neoadjuvant taxane plus trastuzumab and pertuzumab with or without carboplatin, achieving high pathological complete response rates while assessing feasibility of omitting platinum in select patients.[46] A retreatment analysis published in 2025 showed that re-administration of pertuzumab plus trastuzumab improved overall survival (median 25.8 months follow-up) in patients with prior exposure, particularly those without immediate progression post-initial therapy.[47][48] Ongoing trials focus on combinations, biosimilars, and expanded indications. The phase 3 DESTINY-Breast09 follow-up monitors overall survival endpoints. Biosimilar development, such as EG1206A versus reference pertuzumab in HER2-positive early breast cancer, is recruiting to establish equivalence in neoadjuvant settings (NCT06884254).[49] Exploratory studies include pertuzumab with atezolizumab and high-dose trastuzumab for HER2-positive breast cancer with central nervous system metastases (phase 2, results pending).[50] Additional investigations evaluate pertuzumab retreatment in resistant disease and fixed-dose formulations for practicality (e.g., NCT03493854).[51] These efforts aim to optimize sequencing, reduce toxicity, and extend access amid emerging antibody-drug conjugates.[52]Chemistry, Manufacturing, and Formulation
Molecular Structure
![Crystal structure of Pertuzumab in complex with HER2 (PDB: 1S78)][float-right]Pertuzumab is a recombinant humanized monoclonal antibody of the immunoglobulin G1 (IgG1) kappa isotype, engineered from the murine monoclonal antibody 2C4 to target the extracellular dimerization domain (subdomain II) of the human epidermal growth factor receptor 2 (HER2).[2] It consists of two heavy chains, each comprising 448 amino acid residues, and two light chains, each with 214 amino acid residues, linked by disulfide bonds, forming a typical antibody Y-shaped structure with Fab and Fc regions.[53] The molecule is glycosylated, contributing to its effector functions, and has an approximate molecular weight of 148 kDa, excluding the carbohydrate moiety.[10] The variable regions of pertuzumab include complementarity-determining regions (CDRs) derived from the 2C4 clone, humanized by grafting onto human IgG1 frameworks to minimize immunogenicity while preserving binding affinity to HER2.[2] Crystal structures, such as the Fab fragment in complex with HER2 (PDB ID: 1S78), reveal the precise epitope interaction at subdomain II, distinct from the binding site of trastuzumab, enabling complementary inhibition of HER2 dimerization.[53] This structural specificity underlies its role in preventing ligand-independent HER2 heterodimerization.[2]
