Anticancer Drugs Practice Questions

Q: Rituximab is used in all of the following conditions except:

PNH. **Explanation:** **Rituximab** is a chimeric monoclonal antibody directed against the **CD20 antigen**, which is primarily expressed on the surface of mature B-lymphocytes [1]. By binding to CD20, it mediates B-cell lysis through complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity [1]. * **Why PNH is the correct answer:** Paroxysmal Nocturnal Hemoglobinuria (PNH) is a stem cell disorder characterized by a deficiency of GPI-anchored proteins (like CD55 and CD59), leading to complement-mediated hemolysis of RBCs. Rituximab has no role here because the pathology involves the complement system attacking red blood cells, not B-cells. The drug of choice for PNH is **Eculizumab** (a C5 complement inhibitor). * **Why other options are incorrect:** * **NHL (Non-Hodgkin Lymphoma):** Rituximab is a cornerstone of therapy for B-cell NHLs (e.g., Diffuse Large B-cell Lymphoma) because these malignant cells overexpress CD20 [1]. * **RA (Rheumatoid Arthritis):** It is used in refractory RA to deplete the B-cells responsible for producing autoantibodies and presenting antigens to T-cells. * **SLE (Systemic Lupus Erythematosus):** While often used off-label, Rituximab is a recognized treatment for severe or refractory SLE to reduce the B-cell population. **Clinical Pearls for NEET-PG:** 1. **Infusion Reaction:** The most common side effect; managed by pre-medicating with antihistamines and acetaminophen [1]. 2. **HBV Reactivation:** Always screen for Hepatitis B before starting Rituximab, as it can cause fatal viral reactivation [1]. 3. **PML:** It is associated with Progressive Multifocal Leukoencephalopathy (JC virus reactivation) [1]. 4. **Other Indications:** ITP, Pemphigus vulgaris, and Wegener’s Granulomatosis (GPA).

Q: Which of the following is an IL-2 receptor inhibitor?

Both Basiliximab and Daclizumab. **Explanation:** **Mechanism of Action:** Basiliximab and Daclizumab are monoclonal antibodies that function as **IL-2 receptor antagonists**. Specifically, they bind to the **alpha subunit (CD25)** of the IL-2 receptor expressed on the surface of activated T-lymphocytes. By blocking this receptor, they inhibit IL-2 mediated T-cell proliferation, which is a critical step in the cellular immune response. **Analysis of Options:** * **Basiliximab:** A chimeric (murine-human) monoclonal antibody. It has a high affinity for the CD25 receptor and is currently the most commonly used IL-2 receptor antagonist in clinical practice. * **Daclizumab:** A humanized monoclonal antibody. While it also targets the CD25 receptor, it was primarily used for multiple sclerosis but has been largely withdrawn from the market due to safety concerns (hepatic injury). However, pharmacologically, it remains classified as an IL-2 receptor inhibitor. * **Conclusion:** Since both drugs share the same mechanism of inhibiting the IL-2 receptor, **Option C** is the correct answer. **NEET-PG High-Yield Pearls:** 1. **Clinical Use:** These drugs are primarily used for the **prophylaxis of acute organ rejection** in renal transplant patients (induction therapy). 2. **Side Effects:** Generally well-tolerated; however, they can cause hypersensitivity reactions and increased susceptibility to infections. 3. **Mnemonic:** Remember **"BD"** (Basiliximab/Daclizumab) for **"Blocking CD25"**. 4. **Distinction:** Unlike Cyclosporine or Tacrolimus (which inhibit IL-2 *production* via calcineurin inhibition), these drugs inhibit the IL-2 *receptor* directly.

Q: Which anticancer drug, also used in Rheumatoid Arthritis, produces acrolein in urine that leads to hemorrhagic cystitis?

Cyclophosphamide. ### Explanation **Correct Answer: A. Cyclophosphamide** **Mechanism and Pathophysiology:** Cyclophosphamide is an **alkylating agent** (nitrogen mustard) that acts as a prodrug. It is activated in the liver by cytochrome P450 enzymes into 4-hydroxycyclophosphamide, which eventually breaks down into two active metabolites: **phosphoramide mustard** (the cytotoxic component) and **acrolein**. Acrolein is a toxic byproduct excreted in the urine. It causes direct irritation and sloughing of the bladder mucosal lining, leading to **hemorrhagic cystitis**. Clinically, this presents as gross hematuria and dysuria. Beyond oncology, it is widely used as a Disease-Modifying Antirheumatic Drug (DMARD) for severe Rheumatoid Arthritis and systemic vasculitis. **Analysis of Incorrect Options:** * **B. Busulfan:** An alkylating agent primarily used in Chronic Myeloid Leukemia (CML) and bone marrow ablation. Its classic side effects include **pulmonary fibrosis** ("Busulfan lung"), adrenal insufficiency-like syndrome, and skin hyperpigmentation. * **C. Procarbazine:** A methylating agent used in Hodgkin’s lymphoma. It is known for causing **disulfiram-like reactions** with alcohol and hypertensive crises when taken with tyramine-rich foods (MAO inhibition). * **D. Mesna:** This is not an anticancer drug but a **cytoprotective agent**. It is the specific antidote used to *prevent* hemorrhagic cystitis by neutralizing acrolein in the bladder. **NEET-PG High-Yield Pearls:** * **Prevention of Hemorrhagic Cystitis:** Managed by aggressive hydration and administration of **Mesna** (2-MercaptoEthane Sulfonate Na). * **Other Side Effects:** Cyclophosphamide is also associated with SIADH and infertility (premature ovarian failure/azoospermia). * **Ifosfamide:** A related drug that produces even higher levels of acrolein and *always* requires Mesna co-administration.

Q: Which monoclonal antibody is used in the treatment of head and neck cancer?

Pembrolizumab. **Explanation:** **Pembrolizumab** is a humanized monoclonal antibody that targets the **Programmed Cell Death Protein 1 (PD-1)** receptor on T-cells. By blocking the interaction between PD-1 and its ligands (PD-L1/PD-L2), it prevents the "immune checkpoint" inhibition used by tumor cells to evade the immune system. It is FDA-approved for **recurrent or metastatic Squamous Cell Carcinoma of the Head and Neck (HNSCC)**, either as monotherapy or in combination with platinum-based chemotherapy. **Analysis of Incorrect Options:** * **Trastuzumab:** A monoclonal antibody against **HER2/neu** receptors. It is primarily used in HER2-positive breast cancer and gastric adenocarcinoma. * **Rituximab:** A chimeric antibody against the **CD20** antigen found on B-cells. It is the gold standard for B-cell Non-Hodgkin Lymphomas (e.g., Diffuse Large B-cell Lymphoma) and Chronic Lymphocytic Leukemia (CLL). * **Ocrelizumab:** A humanized anti-CD20 antibody used specifically for the treatment of **Multiple Sclerosis (MS)**, not solid tumors. **High-Yield Clinical Pearls for NEET-PG:** * **Cetuximab:** Another high-yield antibody for Head and Neck cancer; it targets the **EGFR** (Epidermal Growth Factor Receptor). * **Nivolumab:** Like Pembrolizumab, it is a PD-1 inhibitor also used in HNSCC. * **Adverse Effect:** Immune-checkpoint inhibitors like Pembrolizumab commonly cause **immune-related Adverse Events (irAEs)**, such as colitis, pneumonitis, and endocrinopathies (hypophysitis).

Q: Maintenance of high urinary pH is important during methotrexate treatment because:

Methotrexate is a weak acid. ### Explanation **1. Why the Correct Answer is Right:** Methotrexate (MTX) is a **weak organic acid** ($pK_a$ ≈ 4.8). In an acidic environment (low pH), it remains in its non-ionized, lipid-soluble form, which is poorly soluble in water. This leads to the precipitation of MTX and its metabolite (7-OH-methotrexate) in the renal tubules, causing **crystalluria and acute kidney injury (AKI)**. By maintaining a **high urinary pH** (alkalinization, usually with Sodium Bicarbonate), the drug is converted into its **ionized (salt) form**. Ionized molecules are highly water-soluble and cannot be easily reabsorbed by the renal tubules, thereby enhancing excretion and preventing crystal-induced nephrotoxicity. **2. Analysis of Incorrect Options:** * **Option A:** While hydration helps, bladder irritation (hemorrhagic cystitis) is specifically associated with Cyclophosphamide/Ifosfamide (due to Acrolein), not MTX. * **Option B:** Alkalinization actually *increases* the clearance of MTX. Decreasing tubular secretion would increase systemic toxicity, which is the opposite of the goal. * **Option C:** Leucovorin (Folinic acid) is the *rescue agent* used to bypass the metabolic block; it does not become "toxic" in dehydrated patients, though its efficacy depends on adequate MTX clearance. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Rescue" Protocol:** High-dose MTX requires **vigorous hydration, urinary alkalinization (pH >7.0), and Leucovorin rescue** (to provide a source of reduced folate for healthy cells). * **Drug Interactions:** Avoid **NSAIDs, Salicylates, and Sulfonamides** with MTX, as they compete for renal tubular secretion and displace MTX from albumin, increasing toxicity. * **Antidote for Toxicity:** In cases of MTX-induced renal failure where clearance is stalled, **Glucarpidase** (carboxypeptidase G2) is used to rapidly break down extracellular MTX.

Q: Rituximab is a targeted antibody against which antigen?

CD 20. **Explanation:** **Rituximab** is a chimeric monoclonal antibody that specifically targets the **CD20 antigen**. CD20 is a transmembrane protein expressed primarily on the surface of pre-B and mature B-lymphocytes, but not on hematopoietic stem cells or plasma cells. When Rituximab binds to CD20, it triggers B-cell lysis through antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and induction of apoptosis. **Analysis of Options:** * **CD 20 (Correct):** The hallmark target for Rituximab. It is used clinically in B-cell Non-Hodgkin Lymphomas (e.g., Diffuse Large B-cell Lymphoma, Follicular Lymphoma), Chronic Lymphocytic Leukemia (CLL), and autoimmune conditions like Rheumatoid Arthritis and Wegener's Granulomatosis. * **CD 22:** This is the target for drugs like **Epratuzumab** and **Inotuzumab ozogamicin**. It is also expressed on B-cells but is distinct from the Rituximab binding site. * **CD 34:** This is a marker for **hematopoietic stem cells**. Targeting this would lead to bone marrow aplasia; it is primarily used in pathology to identify precursors in acute leukemias. * **CD 55:** Also known as Decay-Accelerating Factor (DAF). It protects cells from complement-mediated lysis. Deficiency of CD55 (and CD59) is seen in **Paroxysmal Nocturnal Hemoglobinuria (PNH)**. **High-Yield Clinical Pearls for NEET-PG:** * **Infusion Reaction:** The most common side effect of Rituximab is a cytokine release syndrome during the first infusion (pre-medicate with paracetamol and antihistamines). * **HBV Reactivation:** Always screen for Hepatitis B before starting Rituximab, as it can cause fatal viral reactivation. * **PML:** Rituximab is associated with Progressive Multifocal Leukoencephalopathy (JC virus reactivation).

Q: All of the following are true regarding Erlotinib except:

Food decreases absorption.. **Explanation:** **Erlotinib** is a targeted anticancer therapy belonging to the class of small-molecule **Tyrosine Kinase Inhibitors (TKIs)**. 1. **Why Option C is the correct answer (The Exception):** The statement "Food decreases absorption" is incorrect. In fact, **food significantly increases the bioavailability** of Erlotinib (potentially up to 100%). To ensure consistent drug levels and avoid increased toxicity, it must be taken on an empty stomach (at least 1 hour before or 2 hours after a meal). 2. **Analysis of Incorrect Options:** * **Option A:** Erlotinib is a standard first-line treatment for **Non-Small Cell Lung Carcinoma (NSCLC)**, particularly in patients with activating mutations in the EGFR gene (Exon 19 deletions or Exon 21 L858R mutations). * **Option B:** It acts by competitively inhibiting the ATP-binding site of the intracellular tyrosine kinase domain of the **Epidermal Growth Factor Receptor (EGFR/ErbB1)**, preventing downstream signaling. * **Option D:** The most common adverse effects of EGFR inhibitors are **acneiform skin rashes** (seen in >75% of patients) and **diarrhea**. Interestingly, the severity of the rash often correlates with a better therapeutic response. **High-Yield Clinical Pearls for NEET-PG:** * **Drug Interactions:** Solubility of Erlotinib is pH-dependent. **Proton Pump Inhibitors (PPIs)** and H2 blockers decrease its absorption by increasing gastric pH. * **Smoking:** Cigarette smoking induces CYP1A2, which increases the clearance of Erlotinib, necessitating higher doses in smokers. * **Resistance:** The most common mechanism of acquired resistance to Erlotinib is the **T790M mutation**, for which **Osimertinib** (a 3rd generation TKI) is used.

Q: Which of the following anti-cancer drugs is NOT S-phase specific?

Ifosfamide. **Explanation:** The cell cycle specificity of anticancer drugs is a high-yield concept for NEET-PG. Anticancer agents are broadly classified into **Cell Cycle-Specific (CCS)** and **Cell Cycle-Non-Specific (CCNS)** drugs. **Why Ifosfamide is the correct answer:** Ifosfamide is an **alkylating agent** (a nitrogen mustard derivative). Alkylating agents work by covalently bonding alkyl groups to DNA bases (primarily Guanine), leading to DNA cross-linking and strand breaks. This mechanism occurs regardless of whether the cell is actively dividing or resting. Therefore, Ifosfamide is **Cell Cycle-Non-Specific (CCNS)**. While it is most toxic to cells in the late G1 or S phase, it does not target a specific phase to exert its action. **Why the other options are incorrect:** * **Methotrexate:** An antimetabolite that inhibits *Dihydrofolate Reductase (DHFR)*. It prevents the synthesis of tetrahydrofolate, which is essential for thymidylate and purine synthesis. This process is strictly required during DNA synthesis, making it **S-phase specific**. * **Mercaptopurine (6-MP) & Thioguanine (6-TG):** These are purine analogues. They act as "fraudulent nucleotides" that incorporate into DNA/RNA or inhibit *de novo* purine synthesis. Since DNA replication occurs during the **S-phase**, these drugs are phase-specific. **High-Yield Clinical Pearls for NEET-PG:** 1. **Acrolein Toxicity:** Both Ifosfamide and Cyclophosphamide produce a toxic metabolite called **Acrolein**, which causes **Hemorrhagic Cystitis**. 2. **Prevention:** Hemorrhagic cystitis is prevented by aggressive hydration and **MESNA** (2-Mercaptoethane sulfonate Na), which neutralizes acrolein in the bladder. 3. **Mnemonic for S-phase drugs:** "It’s **S**mart to **MET** at the **PUR**ine **PYR**amid" (**MET**hotrexate, **PUR**ines like 6-MP/6-TG, **PYR**imidines like 5-FU/Cytarabine).

Q: All of the following side effects are produced by Cisplatin except?

Pulmonary fibrosis. **Explanation:** **Cisplatin** is a potent platinum-based alkylating agent used for various solid tumors. The correct answer is **Pulmonary fibrosis**, as this is a classic dose-limiting toxicity associated with **Bleomycin** and **Busulfan**, not Cisplatin. **Why the other options are incorrect (Side effects of Cisplatin):** * **Nephrotoxicity:** This is the most significant dose-limiting toxicity of Cisplatin. It causes acute tubular necrosis. It is managed with aggressive **amifostine** (a cytoprotective agent) and pre-treatment hydration. * **Ototoxicity:** Cisplatin causes high-frequency hearing loss and tinnitus due to damage to the hair cells in the cochlea. This is often irreversible. * **Coasting Effect:** This refers to a unique phenomenon seen with Cisplatin-induced peripheral neuropathy where the neurological symptoms continue to worsen for several weeks even after the drug has been discontinued. * **Emetogenicity:** Though not listed as an option, Cisplatin is the most highly emetogenic chemotherapy drug, requiring prophylaxis with 5-HT3 antagonists (e.g., Ondansetron) and Aprepitant. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Cisplatin toxicity:** "PON" – **P**eripheral neuropathy, **O**totoxicity, **N**ephrotoxicity. * **Carboplatin** is a related drug that is less nephrotoxic and ototoxic but causes more significant **myelosuppression** (thrombocytopenia). * **Oxaliplatin** is notorious for causing **cold-induced peripheral neuropathy**. * To prevent Cisplatin-induced nephrotoxicity, always remember: **Hydration + Chloride diuresis + Amifostine.**

Question 1

Which of the following immunosuppressives does NOT cause profound myelosuppression?

Accepted Answer

Cyclosporine

Answer

Sirolimus

Answer

Azathioprine

Answer

Mercaptopurine

Question 2

Rituximab is used in all of the following conditions except:

Accepted Answer

PNH

Answer

NHL

Answer

RA

Answer

SLE

Question 3

Which of the following is an IL-2 receptor inhibitor?

Accepted Answer

Both Basiliximab and Daclizumab

Answer

Basiliximab

Answer

Daclizumab

Answer

None of the above

Question 4

Which anticancer drug, also used in Rheumatoid Arthritis, produces acrolein in urine that leads to hemorrhagic cystitis?

Accepted Answer

Cyclophosphamide

Answer

Busulfan

Answer

Procarbazine

Answer

Mesna

Question 5

Which monoclonal antibody is used in the treatment of head and neck cancer?

Accepted Answer

Pembrolizumab

Answer

Trastuzumab

Answer

Rituximab

Answer

Ocralizumab

Question 6

Maintenance of high urinary pH is important during methotrexate treatment because:

Accepted Answer

Methotrexate is a weak acid

Answer

Bladder irritation is reduced

Answer

It decreases renal tubular secretion of methotrexate

Answer

Leucovorin toxicity is increased in a dehydrated patient

Question 7

Rituximab is a targeted antibody against which antigen?

Accepted Answer

CD 20

Answer

CD 22

Answer

CD 34

Answer

CD 55

Question 8

All of the following are true regarding Erlotinib except:

Accepted Answer

Food decreases absorption.

Answer

Used in non-small cell carcinoma of the lung.

Answer

It is a small molecule tyrosine kinase inhibitor acting as an EGFR antagonist.

Answer

It causes skin rashes and diarrhea.

Question 9

Which of the following anti-cancer drugs is NOT S-phase specific?

Accepted Answer

Ifosfamide

Answer

Methotrexate

Answer

Mercaptopurine

Answer

Thioguanine

Question 10

All of the following side effects are produced by Cisplatin except?

Accepted Answer

Pulmonary fibrosis

Answer

Ototoxicity

Answer

Nephrotoxicity

Answer

Coasting effect

Anticancer Drugs — MCQs

Anticancer Drugs — MCQs

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