Lynparza (olaparib) is neither chemotherapy nor immunotherapy. It belongs to a third category called targeted therapy, specifically a class of drugs known as PARP inhibitors. While chemotherapy attacks all rapidly dividing cells and immunotherapy activates your immune system against cancer, Lynparza works by exploiting a specific weakness in cancer cells that have trouble repairing their own DNA.
How Lynparza Actually Works
Your cells constantly sustain minor DNA damage, and they rely on repair systems to fix it. One key repair tool is an enzyme called PARP, which detects single-strand DNA breaks and helps patch them up. Lynparza blocks PARP from doing its job and physically traps it at the damage site, preventing the repair machinery from moving forward. In healthy cells, a backup repair system (called homologous recombination) can step in and fix the damage through a different route.
Cancer cells with BRCA1 or BRCA2 gene mutations don’t have that backup system. When Lynparza shuts down PARP, these cells have no way to fix their DNA at all. The damage accumulates, the DNA breaks get worse, and the cancer cells die. This two-hit concept, where losing both repair pathways is fatal to the cell, is known as synthetic lethality. It’s what makes Lynparza effective against BRCA-mutated cancers while largely sparing normal cells that still have functioning backup repair.
Why It’s Not Chemotherapy
Traditional chemotherapy drugs are cytotoxic, meaning they poison or destroy cells that are actively dividing. That broad mechanism is why chemotherapy causes widespread side effects like hair loss, severe nausea, and immune suppression: it hits healthy dividing cells alongside cancer cells. Lynparza is far more selective. It targets a specific molecular vulnerability, which is why clinicians who reviewed the drug for Canadian regulatory approval noted that PARP inhibitors have a “superior toxicity profile compared to chemotherapy.”
That said, Lynparza is not side-effect-free. Nausea affects over 75% of patients, though severe nausea is uncommon (1% to 2%). Fatigue occurs in roughly 60% to 70% of patients, with most cases being mild. The most significant blood-related side effect is anemia: about 22% of patients on Lynparza in first-line ovarian cancer maintenance trials developed moderate to severe anemia. These side effects are real but generally more manageable than the toxicities associated with intravenous chemotherapy.
Why It’s Not Immunotherapy
Immunotherapy drugs like checkpoint inhibitors work by releasing the brakes on your immune system so it can recognize and attack cancer cells. Lynparza does something entirely different. It directly damages cancer cells’ ability to survive by disabling their DNA repair. The two approaches operate through completely separate biological pathways.
Interestingly, there is some overlap between the two strategies. PARP inhibitors can increase the number of DNA mutations in tumor cells, which causes those cells to display more abnormal proteins on their surface. This makes them more visible to the immune system. Lynparza can also trigger an innate immune signaling pathway that produces inflammatory molecules, potentially making the tumor environment more responsive to immunotherapy. This is why researchers are actively studying combinations of PARP inhibitors with checkpoint inhibitors, but Lynparza on its own is not an immunotherapy drug.
How Lynparza Is Used in Treatment
Lynparza is most commonly prescribed as maintenance therapy, meaning you take it after your cancer has responded to an initial round of platinum-based chemotherapy. The goal is to keep the cancer from coming back for as long as possible, rather than to shrink an existing tumor. In the landmark SOLO-1 trial, nearly 400 women with advanced ovarian cancer who had responded to first-line chemotherapy were randomly assigned to take either Lynparza or a placebo for up to two years.
One of the practical advantages is that Lynparza is a pill you take at home. The standard dose is two 150 mg tablets twice daily, with or without food. You don’t need to go to an infusion center. Treatment continues until the cancer progresses or side effects become unmanageable. For many patients, delaying the need for another round of chemotherapy is a meaningful benefit, since each successive line of chemotherapy tends to be less effective, shorter-lasting, and harder to tolerate.
Who Is Eligible for Lynparza
Because Lynparza exploits a specific DNA repair deficiency, not every cancer patient is a candidate. Eligibility depends on your cancer type and your tumor’s genetic profile. The FDA has approved Lynparza for several cancers:
- Ovarian cancer: As maintenance therapy for advanced ovarian, fallopian tube, or primary peritoneal cancer with BRCA mutations after response to platinum-based chemotherapy. It’s also approved in combination with bevacizumab for tumors that test positive for a broader category of DNA repair problems called homologous recombination deficiency (HRD).
- Breast cancer: For HER2-negative early breast cancer with inherited BRCA mutations after chemotherapy, and for metastatic HER2-negative breast cancer with inherited BRCA mutations.
- Pancreatic cancer: As maintenance therapy for metastatic pancreatic cancer with inherited BRCA mutations, after at least 16 weeks of stable disease on platinum-based chemotherapy.
- Prostate cancer: For certain advanced prostate cancers with specific DNA repair gene mutations.
Genetic testing is a prerequisite. For most indications, you’ll need either a blood test to check for inherited BRCA mutations or a tumor biopsy to identify somatic BRCA mutations or HRD status. Without confirmation that your cancer has the right molecular profile, Lynparza is unlikely to provide meaningful benefit, since the drug’s entire mechanism depends on that missing backup repair system in cancer cells.